SERVER-27938 Rename all OperationContext variables to opCtx

This commit is an automated rename of all whole word instances of txn,
_txn, and txnPtr to opCtx, _opCtx, and opCtxPtr, respectively in all
.cpp and .h files in src/mongo.

72 files changed, 1246 insertions, 1202 deletions

diff --git a/src/mongo/db/commands/apply_ops_cmd.cpp b/src/mongo/db/commands/apply_ops_cmd.cpp
index c252b8fd073..233fcc744e3 100644
--- a/src/mongo/db/commands/apply_ops_cmd.cpp
+++ b/src/mongo/db/commands/apply_ops_cmd.cpp
@@ -80,13 +80,13 @@ public:
     }
 
 
-    virtual Status checkAuthForOperation(OperationContext* txn,
+    virtual Status checkAuthForOperation(OperationContext* opCtx,
                                          const std::string& dbname,
                                          const BSONObj& cmdObj) {
-        return checkAuthForApplyOpsCommand(txn, dbname, cmdObj);
+        return checkAuthForApplyOpsCommand(opCtx, dbname, cmdObj);
     }
 
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const string& dbname,
                      BSONObj& cmdObj,
                      int,
@@ -96,7 +96,7 @@ public:
 
         boost::optional<DisableDocumentValidation> maybeDisableValidation;
         if (shouldBypassDocumentValidationForCommand(cmdObj))
-            maybeDisableValidation.emplace(txn);
+            maybeDisableValidation.emplace(opCtx);
 
         if (cmdObj.firstElement().type() != Array) {
             errmsg = "ops has to be an array";
@@ -116,14 +116,14 @@ public:
             }
         }
 
-        auto client = txn->getClient();
+        auto client = opCtx->getClient();
         auto lastOpAtOperationStart = repl::ReplClientInfo::forClient(client).getLastOp();
         ScopeGuard lastOpSetterGuard =
             MakeObjGuard(repl::ReplClientInfo::forClient(client),
                          &repl::ReplClientInfo::setLastOpToSystemLastOpTime,
-                         txn);
+                         opCtx);
 
-        auto applyOpsStatus = appendCommandStatus(result, applyOps(txn, dbname, cmdObj, &result));
+        auto applyOpsStatus = appendCommandStatus(result, applyOps(opCtx, dbname, cmdObj, &result));
 
         if (repl::ReplClientInfo::forClient(client).getLastOp() != lastOpAtOperationStart) {
             // If this operation has already generated a new lastOp, don't bother setting it
diff --git a/src/mongo/db/commands/apply_ops_cmd_common.cpp b/src/mongo/db/commands/apply_ops_cmd_common.cpp
index ebacbdfd476..55b463abc04 100644
--- a/src/mongo/db/commands/apply_ops_cmd_common.cpp
+++ b/src/mongo/db/commands/apply_ops_cmd_common.cpp
@@ -46,11 +46,11 @@ namespace mongo {
 
 namespace {
 
-Status checkOperationAuthorization(OperationContext* txn,
+Status checkOperationAuthorization(OperationContext* opCtx,
                                    const std::string& dbname,
                                    const BSONObj& oplogEntry,
                                    bool alwaysUpsert) {
-    AuthorizationSession* authSession = AuthorizationSession::get(txn->getClient());
+    AuthorizationSession* authSession = AuthorizationSession::get(opCtx->getClient());
 
     BSONElement opTypeElem = oplogEntry["op"];
     checkBSONType(BSONType::String, opTypeElem);
@@ -79,11 +79,11 @@ Status checkOperationAuthorization(OperationContext* txn,
             return Status(ErrorCodes::FailedToParse, "Unrecognized command in op");
         }
 
-        return Command::checkAuthorization(command, txn, dbname, o);
+        return Command::checkAuthorization(command, opCtx, dbname, o);
     }
 
     if (opType == "i"_sd) {
-        return authSession->checkAuthForInsert(txn, ns, o);
+        return authSession->checkAuthForInsert(opCtx, ns, o);
     } else if (opType == "u"_sd) {
         BSONElement o2Elem = oplogEntry["o2"];
         checkBSONType(BSONType::Object, o2Elem);
@@ -97,10 +97,10 @@ Status checkOperationAuthorization(OperationContext* txn,
 
         const bool upsert = b || alwaysUpsert;
 
-        return authSession->checkAuthForUpdate(txn, ns, o, o2, upsert);
+        return authSession->checkAuthForUpdate(opCtx, ns, o, o2, upsert);
     } else if (opType == "d"_sd) {
 
-        return authSession->checkAuthForDelete(txn, ns, o);
+        return authSession->checkAuthForDelete(opCtx, ns, o);
     } else if (opType == "db"_sd) {
         // It seems that 'db' isn't used anymore. Require all actions to prevent casual use.
         ActionSet allActions;
@@ -175,10 +175,10 @@ ApplyOpsValidity validateApplyOpsCommand(const BSONObj& cmdObj) {
     return ApplyOpsValidity::kOk;
 }
 
-Status checkAuthForApplyOpsCommand(OperationContext* txn,
+Status checkAuthForApplyOpsCommand(OperationContext* opCtx,
                                    const std::string& dbname,
                                    const BSONObj& cmdObj) {
-    AuthorizationSession* authSession = AuthorizationSession::get(txn->getClient());
+    AuthorizationSession* authSession = AuthorizationSession::get(opCtx->getClient());
 
     ApplyOpsValidity validity = validateApplyOpsCommand(cmdObj);
     if (validity == ApplyOpsValidity::kNeedsSuperuser) {
@@ -193,7 +193,7 @@ Status checkAuthForApplyOpsCommand(OperationContext* txn,
 
     boost::optional<DisableDocumentValidation> maybeDisableValidation;
     if (shouldBypassDocumentValidationForCommand(cmdObj))
-        maybeDisableValidation.emplace(txn);
+        maybeDisableValidation.emplace(opCtx);
 
 
     const bool alwaysUpsert =
@@ -202,7 +202,7 @@ Status checkAuthForApplyOpsCommand(OperationContext* txn,
     checkBSONType(BSONType::Array, cmdObj.firstElement());
     for (const BSONElement& e : cmdObj.firstElement().Array()) {
         checkBSONType(BSONType::Object, e);
-        Status status = checkOperationAuthorization(txn, dbname, e.Obj(), alwaysUpsert);
+        Status status = checkOperationAuthorization(opCtx, dbname, e.Obj(), alwaysUpsert);
         if (!status.isOK()) {
             return status;
         }
diff --git a/src/mongo/db/commands/apply_ops_cmd_common.h b/src/mongo/db/commands/apply_ops_cmd_common.h
index 443e862b798..f9fb5ec9823 100644
--- a/src/mongo/db/commands/apply_ops_cmd_common.h
+++ b/src/mongo/db/commands/apply_ops_cmd_common.h
@@ -39,7 +39,7 @@ class Status;
 /**
  * Returns Status::OK if the associated client is authorized to perform the command in cmdObj.
  */
-Status checkAuthForApplyOpsCommand(OperationContext* txn,
+Status checkAuthForApplyOpsCommand(OperationContext* opCtx,
                                    const std::string& dbname,
                                    const BSONObj& cmdObj);
 
diff --git a/src/mongo/db/commands/authentication_commands.cpp b/src/mongo/db/commands/authentication_commands.cpp
index 8de3931d529..95a92d89e3a 100644
--- a/src/mongo/db/commands/authentication_commands.cpp
+++ b/src/mongo/db/commands/authentication_commands.cpp
@@ -113,7 +113,7 @@ public:
     virtual void addRequiredPrivileges(const std::string& dbname,
                                        const BSONObj& cmdObj,
                                        std::vector<Privilege>* out) {}  // No auth required
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string&,
              BSONObj& cmdObj,
              int,
@@ -151,7 +151,7 @@ void CmdAuthenticate::redactForLogging(mutablebson::Document* cmdObj) {
     }
 }
 
-bool CmdAuthenticate::run(OperationContext* txn,
+bool CmdAuthenticate::run(OperationContext* opCtx,
                           const string& dbname,
                           BSONObj& cmdObj,
                           int,
@@ -167,7 +167,7 @@ bool CmdAuthenticate::run(OperationContext* txn,
         mechanism = "MONGODB-CR";
     }
     UserName user;
-    auto& sslPeerInfo = SSLPeerInfo::forSession(txn->getClient()->session());
+    auto& sslPeerInfo = SSLPeerInfo::forSession(opCtx->getClient()->session());
     if (mechanism == "MONGODB-X509" && !cmdObj.hasField("user")) {
         user = UserName(sslPeerInfo.subjectName, dbname);
     } else {
@@ -182,7 +182,7 @@ bool CmdAuthenticate::run(OperationContext* txn,
         user = internalSecurity.user->getName();
     }
 
-    Status status = _authenticate(txn, mechanism, user, cmdObj);
+    Status status = _authenticate(opCtx, mechanism, user, cmdObj);
     audit::logAuthentication(Client::getCurrent(), mechanism, user, status.code());
     if (!status.isOK()) {
         if (!serverGlobalParams.quiet.load()) {
@@ -204,22 +204,22 @@ bool CmdAuthenticate::run(OperationContext* txn,
     return true;
 }
 
-Status CmdAuthenticate::_authenticate(OperationContext* txn,
+Status CmdAuthenticate::_authenticate(OperationContext* opCtx,
                                       const std::string& mechanism,
                                       const UserName& user,
                                       const BSONObj& cmdObj) {
     if (mechanism == "MONGODB-CR") {
-        return _authenticateCR(txn, user, cmdObj);
+        return _authenticateCR(opCtx, user, cmdObj);
     }
 #ifdef MONGO_CONFIG_SSL
     if (mechanism == "MONGODB-X509") {
-        return _authenticateX509(txn, user, cmdObj);
+        return _authenticateX509(opCtx, user, cmdObj);
     }
 #endif
     return Status(ErrorCodes::BadValue, "Unsupported mechanism: " + mechanism);
 }
 
-Status CmdAuthenticate::_authenticateCR(OperationContext* txn,
+Status CmdAuthenticate::_authenticateCR(OperationContext* opCtx,
                                         const UserName& user,
                                         const BSONObj& cmdObj) {
     if (user == internalSecurity.user->getName() &&
@@ -265,7 +265,7 @@ Status CmdAuthenticate::_authenticateCR(OperationContext* txn,
     }
 
     User* userObj;
-    Status status = getGlobalAuthorizationManager()->acquireUser(txn, user, &userObj);
+    Status status = getGlobalAuthorizationManager()->acquireUser(opCtx, user, &userObj);
     if (!status.isOK()) {
         // Failure to find the privilege document indicates no-such-user, a fact that we do not
         // wish to reveal to the client.  So, we return AuthenticationFailed rather than passing
@@ -298,7 +298,7 @@ Status CmdAuthenticate::_authenticateCR(OperationContext* txn,
     }
 
     AuthorizationSession* authorizationSession = AuthorizationSession::get(Client::getCurrent());
-    status = authorizationSession->addAndAuthorizeUser(txn, user);
+    status = authorizationSession->addAndAuthorizeUser(opCtx, user);
     if (!status.isOK()) {
         return status;
     }
@@ -307,7 +307,7 @@ Status CmdAuthenticate::_authenticateCR(OperationContext* txn,
 }
 
 #ifdef MONGO_CONFIG_SSL
-Status CmdAuthenticate::_authenticateX509(OperationContext* txn,
+Status CmdAuthenticate::_authenticateX509(OperationContext* opCtx,
                                           const UserName& user,
                                           const BSONObj& cmdObj) {
     if (!getSSLManager()) {
@@ -348,7 +348,7 @@ Status CmdAuthenticate::_authenticateX509(OperationContext* txn,
             if (_isX509AuthDisabled) {
                 return Status(ErrorCodes::BadValue, _x509AuthenticationDisabledMessage);
             }
-            Status status = authorizationSession->addAndAuthorizeUser(txn, user);
+            Status status = authorizationSession->addAndAuthorizeUser(opCtx, user);
             if (!status.isOK()) {
                 return status;
             }
@@ -374,7 +374,7 @@ public:
         return false;
     }
     CmdLogout() : Command("logout") {}
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int options,
diff --git a/src/mongo/db/commands/authentication_commands.h b/src/mongo/db/commands/authentication_commands.h
index 4b1caf54913..fddfcfdb1eb 100644
--- a/src/mongo/db/commands/authentication_commands.h
+++ b/src/mongo/db/commands/authentication_commands.h
@@ -55,7 +55,7 @@ public:
     virtual void redactForLogging(mutablebson::Document* cmdObj);
 
     CmdAuthenticate() : Command("authenticate") {}
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const std::string& dbname,
              BSONObj& cmdObj,
              int options,
@@ -75,12 +75,12 @@ private:
      * mechanism, and ProtocolError, indicating an error in the use of the authentication
      * protocol.
      */
-    Status _authenticate(OperationContext* txn,
+    Status _authenticate(OperationContext* opCtx,
                          const std::string& mechanism,
                          const UserName& user,
                          const BSONObj& cmdObj);
-    Status _authenticateCR(OperationContext* txn, const UserName& user, const BSONObj& cmdObj);
-    Status _authenticateX509(OperationContext* txn, const UserName& user, const BSONObj& cmdObj);
+    Status _authenticateCR(OperationContext* opCtx, const UserName& user, const BSONObj& cmdObj);
+    Status _authenticateX509(OperationContext* opCtx, const UserName& user, const BSONObj& cmdObj);
 };
 
 extern CmdAuthenticate cmdAuthenticate;
diff --git a/src/mongo/db/commands/clone.cpp b/src/mongo/db/commands/clone.cpp
index 60b9d031dc1..8548152087d 100644
--- a/src/mongo/db/commands/clone.cpp
+++ b/src/mongo/db/commands/clone.cpp
@@ -86,7 +86,7 @@ public:
         return Status::OK();
     }
 
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const string& dbname,
                      BSONObj& cmdObj,
                      int,
@@ -94,7 +94,7 @@ public:
                      BSONObjBuilder& result) {
         boost::optional<DisableDocumentValidation> maybeDisableValidation;
         if (shouldBypassDocumentValidationForCommand(cmdObj)) {
-            maybeDisableValidation.emplace(txn);
+            maybeDisableValidation.emplace(opCtx);
         }
 
         string from = cmdObj.getStringField("clone");
@@ -119,11 +119,11 @@ public:
 
         set<string> clonedColls;
 
-        ScopedTransaction transaction(txn, MODE_IX);
-        Lock::DBLock dbXLock(txn->lockState(), dbname, MODE_X);
+        ScopedTransaction transaction(opCtx, MODE_IX);
+        Lock::DBLock dbXLock(opCtx->lockState(), dbname, MODE_X);
 
         Cloner cloner;
-        Status status = cloner.copyDb(txn, dbname, from, opts, &clonedColls);
+        Status status = cloner.copyDb(opCtx, dbname, from, opts, &clonedColls);
 
         BSONArrayBuilder barr;
         barr.append(clonedColls);
diff --git a/src/mongo/db/commands/clone_collection.cpp b/src/mongo/db/commands/clone_collection.cpp
index 512c9d7b737..d920ac62c05 100644
--- a/src/mongo/db/commands/clone_collection.cpp
+++ b/src/mongo/db/commands/clone_collection.cpp
@@ -103,7 +103,7 @@ public:
                 "is placed at the same db.collection (namespace) as the source.\n";
     }
 
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const string& dbname,
                      BSONObj& cmdObj,
                      int,
@@ -111,7 +111,7 @@ public:
                      BSONObjBuilder& result) {
         boost::optional<DisableDocumentValidation> maybeDisableValidation;
         if (shouldBypassDocumentValidationForCommand(cmdObj))
-            maybeDisableValidation.emplace(txn);
+            maybeDisableValidation.emplace(opCtx);
 
         string fromhost = cmdObj.getStringField("from");
         if (fromhost.empty()) {
@@ -121,7 +121,7 @@ public:
 
         {
             HostAndPort h(fromhost);
-            if (repl::isSelf(h, txn->getServiceContext())) {
+            if (repl::isSelf(h, opCtx->getServiceContext())) {
                 errmsg = "can't cloneCollection from self";
                 return false;
             }
@@ -152,7 +152,7 @@ public:
 
         cloner.setConnection(myconn.release());
 
-        return cloner.copyCollection(txn, collection, query, errmsg, copyIndexes);
+        return cloner.copyCollection(opCtx, collection, query, errmsg, copyIndexes);
     }
 
 } cmdCloneCollection;
diff --git a/src/mongo/db/commands/collection_to_capped.cpp b/src/mongo/db/commands/collection_to_capped.cpp
index 373147da069..222e6d8887f 100644
--- a/src/mongo/db/commands/collection_to_capped.cpp
+++ b/src/mongo/db/commands/collection_to_capped.cpp
@@ -84,7 +84,7 @@ public:
 
         out->push_back(Privilege(ResourcePattern::forExactNamespace(nss), targetActions));
     }
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& jsobj,
              int,
@@ -118,11 +118,11 @@ public:
             return false;
         }
 
-        ScopedTransaction transaction(txn, MODE_IX);
-        AutoGetDb autoDb(txn, dbname, MODE_X);
+        ScopedTransaction transaction(opCtx, MODE_IX);
+        AutoGetDb autoDb(opCtx, dbname, MODE_X);
 
         NamespaceString nss(dbname, to);
-        if (!repl::getGlobalReplicationCoordinator()->canAcceptWritesFor(txn, nss)) {
+        if (!repl::getGlobalReplicationCoordinator()->canAcceptWritesFor(opCtx, nss)) {
             return appendCommandStatus(
                 result,
                 Status(ErrorCodes::NotMaster,
@@ -140,7 +140,7 @@ public:
         }
 
         Status status =
-            cloneCollectionAsCapped(txn, db, from.toString(), to.toString(), size, temp);
+            cloneCollectionAsCapped(opCtx, db, from.toString(), to.toString(), size, temp);
         return appendCommandStatus(result, status);
     }
 } cmdCloneCollectionAsCapped;
@@ -170,7 +170,7 @@ public:
         out->push_back(Privilege(parseResourcePattern(dbname, cmdObj), actions));
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& jsobj,
              int,
@@ -184,7 +184,7 @@ public:
             return false;
         }
 
-        return appendCommandStatus(result, convertToCapped(txn, nss, size));
+        return appendCommandStatus(result, convertToCapped(opCtx, nss, size));
     }
 
 } cmdConvertToCapped;
diff --git a/src/mongo/db/commands/compact.cpp b/src/mongo/db/commands/compact.cpp
index b53fcda0b65..e93b94a5892 100644
--- a/src/mongo/db/commands/compact.cpp
+++ b/src/mongo/db/commands/compact.cpp
@@ -86,7 +86,7 @@ public:
     }
     CompactCmd() : Command("compact") {}
 
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const string& db,
                      BSONObj& cmdObj,
                      int,
@@ -144,13 +144,13 @@ public:
         if (cmdObj.hasElement("validate"))
             compactOptions.validateDocuments = cmdObj["validate"].trueValue();
 
-        ScopedTransaction transaction(txn, MODE_IX);
-        AutoGetDb autoDb(txn, db, MODE_X);
+        ScopedTransaction transaction(opCtx, MODE_IX);
+        AutoGetDb autoDb(opCtx, db, MODE_X);
         Database* const collDB = autoDb.getDb();
 
         Collection* collection = collDB ? collDB->getCollection(nss) : nullptr;
         auto view =
-            collDB && !collection ? collDB->getViewCatalog()->lookup(txn, nss.ns()) : nullptr;
+            collDB && !collection ? collDB->getViewCatalog()->lookup(opCtx, nss.ns()) : nullptr;
 
         // If db/collection does not exist, short circuit and return.
         if (!collDB || !collection) {
@@ -162,12 +162,12 @@ public:
                     result, {ErrorCodes::NamespaceNotFound, "collection does not exist"});
         }
 
-        OldClientContext ctx(txn, nss.ns());
+        OldClientContext ctx(opCtx, nss.ns());
         BackgroundOperation::assertNoBgOpInProgForNs(nss.ns());
 
         log() << "compact " << nss.ns() << " begin, options: " << compactOptions;
 
-        StatusWith<CompactStats> status = collection->compact(txn, &compactOptions);
+        StatusWith<CompactStats> status = collection->compact(opCtx, &compactOptions);
         if (!status.isOK())
             return appendCommandStatus(result, status.getStatus());
 
diff --git a/src/mongo/db/commands/conn_pool_stats.cpp b/src/mongo/db/commands/conn_pool_stats.cpp
index 2cd000e7d30..1d23df5060d 100644
--- a/src/mongo/db/commands/conn_pool_stats.cpp
+++ b/src/mongo/db/commands/conn_pool_stats.cpp
@@ -69,7 +69,7 @@ public:
         out->push_back(Privilege(ResourcePattern::forClusterResource(), actions));
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const std::string&,
              mongo::BSONObj&,
              int,
@@ -83,13 +83,13 @@ public:
         result.appendNumber("numAScopedConnections", AScopedConnection::getNumConnections());
 
         // Replication connections, if we have them.
-        auto replCoord = repl::ReplicationCoordinator::get(txn);
+        auto replCoord = repl::ReplicationCoordinator::get(opCtx);
         if (replCoord && replCoord->isReplEnabled()) {
             replCoord->appendConnectionStats(&stats);
         }
 
         // Sharding connections, if we have any.
-        auto grid = Grid::get(txn);
+        auto grid = Grid::get(opCtx);
         if (grid->shardRegistry()) {
             grid->getExecutorPool()->appendConnectionStats(&stats);
             if (serverGlobalParams.clusterRole == ClusterRole::ConfigServer) {
diff --git a/src/mongo/db/commands/conn_pool_sync.cpp b/src/mongo/db/commands/conn_pool_sync.cpp
index cb9410d7619..e3318079efd 100644
--- a/src/mongo/db/commands/conn_pool_sync.cpp
+++ b/src/mongo/db/commands/conn_pool_sync.cpp
@@ -54,7 +54,7 @@ public:
         out->push_back(Privilege(ResourcePattern::forClusterResource(), actions));
     }
 
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const std::string&,
                      mongo::BSONObj&,
                      int,
diff --git a/src/mongo/db/commands/connection_status.cpp b/src/mongo/db/commands/connection_status.cpp
index e26e6b9d192..651a84327fa 100644
--- a/src/mongo/db/commands/connection_status.cpp
+++ b/src/mongo/db/commands/connection_status.cpp
@@ -55,7 +55,7 @@ public:
         h << "Returns connection-specific information such as logged-in users and their roles";
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string&,
              BSONObj& cmdObj,
              int,
diff --git a/src/mongo/db/commands/copydb.cpp b/src/mongo/db/commands/copydb.cpp
index 00f26f8bd4d..b13066949df 100644
--- a/src/mongo/db/commands/copydb.cpp
+++ b/src/mongo/db/commands/copydb.cpp
@@ -114,7 +114,7 @@ public:
              << "[, slaveOk: <bool>, username: <username>, nonce: <nonce>, key: <key>]}";
     }
 
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const string& dbname,
                      BSONObj& cmdObj,
                      int,
@@ -122,7 +122,7 @@ public:
                      BSONObjBuilder& result) {
         boost::optional<DisableDocumentValidation> maybeDisableValidation;
         if (shouldBypassDocumentValidationForCommand(cmdObj))
-            maybeDisableValidation.emplace(txn);
+            maybeDisableValidation.emplace(opCtx);
 
         string fromhost = cmdObj.getStringField("fromhost");
         bool fromSelf = fromhost.empty();
@@ -171,7 +171,7 @@ public:
         string nonce = cmdObj.getStringField("nonce");
         string key = cmdObj.getStringField("key");
 
-        auto& authConn = CopyDbAuthConnection::forClient(txn->getClient());
+        auto& authConn = CopyDbAuthConnection::forClient(opCtx->getClient());
 
         if (!username.empty() && !nonce.empty() && !key.empty()) {
             uassert(13008, "must call copydbgetnonce first", authConn.get());
@@ -226,13 +226,13 @@ public:
 
         if (fromSelf) {
             // SERVER-4328 todo lock just the two db's not everything for the fromself case
-            ScopedTransaction transaction(txn, MODE_X);
-            Lock::GlobalWrite lk(txn->lockState());
-            uassertStatusOK(cloner.copyDb(txn, todb, fromhost, cloneOptions, NULL));
+            ScopedTransaction transaction(opCtx, MODE_X);
+            Lock::GlobalWrite lk(opCtx->lockState());
+            uassertStatusOK(cloner.copyDb(opCtx, todb, fromhost, cloneOptions, NULL));
         } else {
-            ScopedTransaction transaction(txn, MODE_IX);
-            Lock::DBLock lk(txn->lockState(), todb, MODE_X);
-            uassertStatusOK(cloner.copyDb(txn, todb, fromhost, cloneOptions, NULL));
+            ScopedTransaction transaction(opCtx, MODE_IX);
+            Lock::DBLock lk(opCtx->lockState(), todb, MODE_X);
+            uassertStatusOK(cloner.copyDb(opCtx, todb, fromhost, cloneOptions, NULL));
         }
 
         return true;
diff --git a/src/mongo/db/commands/copydb_start_commands.cpp b/src/mongo/db/commands/copydb_start_commands.cpp
index 3dc9769024a..f7a8949ca42 100644
--- a/src/mongo/db/commands/copydb_start_commands.cpp
+++ b/src/mongo/db/commands/copydb_start_commands.cpp
@@ -96,7 +96,7 @@ public:
         help << "usage: {copydbgetnonce: 1, fromhost: <hostname>}";
     }
 
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const string&,
                      BSONObj& cmdObj,
                      int,
@@ -112,7 +112,7 @@ public:
 
         const ConnectionString cs(uassertStatusOK(ConnectionString::parse(fromhost)));
 
-        auto& authConn = CopyDbAuthConnection::forClient(txn->getClient());
+        auto& authConn = CopyDbAuthConnection::forClient(opCtx->getClient());
         authConn.reset(cs.connect(StringData(), errmsg));
         if (!authConn) {
             return false;
@@ -170,7 +170,7 @@ public:
                 "from secure server\n";
     }
 
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const string&,
                      BSONObj& cmdObj,
                      int,
@@ -209,7 +209,7 @@ public:
             return false;
         }
 
-        auto& authConn = CopyDbAuthConnection::forClient(txn->getClient());
+        auto& authConn = CopyDbAuthConnection::forClient(opCtx->getClient());
         authConn.reset(cs.connect(StringData(), errmsg));
         if (!authConn.get()) {
             return false;
diff --git a/src/mongo/db/commands/count_cmd.cpp b/src/mongo/db/commands/count_cmd.cpp
index 8c1bb515738..7ecbe2f08ea 100644
--- a/src/mongo/db/commands/count_cmd.cpp
+++ b/src/mongo/db/commands/count_cmd.cpp
@@ -101,7 +101,7 @@ public:
         out->push_back(Privilege(parseResourcePattern(dbname, cmdObj), actions));
     }
 
-    virtual Status explain(OperationContext* txn,
+    virtual Status explain(OperationContext* opCtx,
                            const std::string& dbname,
                            const BSONObj& cmdObj,
                            ExplainCommon::Verbosity verbosity,
@@ -122,7 +122,7 @@ public:
         }
 
         // Acquire the db read lock.
-        AutoGetCollectionOrViewForRead ctx(txn, request.getValue().getNs());
+        AutoGetCollectionOrViewForRead ctx(opCtx, request.getValue().getNs());
         Collection* collection = ctx.getCollection();
 
         if (ctx.getView()) {
@@ -135,7 +135,7 @@ public:
 
             std::string errmsg;
             (void)Command::findCommand("aggregate")
-                ->run(txn, dbname, viewAggregation.getValue(), 0, errmsg, *out);
+                ->run(opCtx, dbname, viewAggregation.getValue(), 0, errmsg, *out);
             return Status::OK();
         }
 
@@ -143,7 +143,7 @@ public:
         // version on initial entry into count.
         RangePreserver preserver(collection);
 
-        auto statusWithPlanExecutor = getExecutorCount(txn,
+        auto statusWithPlanExecutor = getExecutorCount(opCtx,
                                                        collection,
                                                        request.getValue(),
                                                        true,  // explain
@@ -158,7 +158,7 @@ public:
         return Status::OK();
     }
 
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const string& dbname,
                      BSONObj& cmdObj,
                      int options,
@@ -180,7 +180,7 @@ public:
                        "http://dochub.mongodb.org/core/3.4-feature-compatibility."));
         }
 
-        AutoGetCollectionOrViewForRead ctx(txn, request.getValue().getNs());
+        AutoGetCollectionOrViewForRead ctx(opCtx, request.getValue().getNs());
         Collection* collection = ctx.getCollection();
 
         if (ctx.getView()) {
@@ -193,7 +193,7 @@ public:
 
             BSONObjBuilder aggResult;
             (void)Command::findCommand("aggregate")
-                ->run(txn, dbname, viewAggregation.getValue(), options, errmsg, aggResult);
+                ->run(opCtx, dbname, viewAggregation.getValue(), options, errmsg, aggResult);
 
             if (ResolvedView::isResolvedViewErrorResponse(aggResult.asTempObj())) {
                 result.appendElements(aggResult.obj());
@@ -212,7 +212,7 @@ public:
         // version on initial entry into count.
         RangePreserver preserver(collection);
 
-        auto statusWithPlanExecutor = getExecutorCount(txn,
+        auto statusWithPlanExecutor = getExecutorCount(opCtx,
                                                        collection,
                                                        request.getValue(),
                                                        false,  // !explain
@@ -224,9 +224,9 @@ public:
         unique_ptr<PlanExecutor> exec = std::move(statusWithPlanExecutor.getValue());
 
         // Store the plan summary string in CurOp.
-        auto curOp = CurOp::get(txn);
+        auto curOp = CurOp::get(opCtx);
         {
-            stdx::lock_guard<Client> lk(*txn->getClient());
+            stdx::lock_guard<Client> lk(*opCtx->getClient());
             curOp->setPlanSummary_inlock(Explain::getPlanSummary(exec.get()));
         }
 
@@ -238,7 +238,7 @@ public:
         PlanSummaryStats summaryStats;
         Explain::getSummaryStats(*exec, &summaryStats);
         if (collection) {
-            collection->infoCache()->notifyOfQuery(txn, summaryStats.indexesUsed);
+            collection->infoCache()->notifyOfQuery(opCtx, summaryStats.indexesUsed);
         }
         curOp->debug().setPlanSummaryMetrics(summaryStats);
 
diff --git a/src/mongo/db/commands/cpuprofile.cpp b/src/mongo/db/commands/cpuprofile.cpp
index 24fbd034b81..608a626aa92 100644
--- a/src/mongo/db/commands/cpuprofile.cpp
+++ b/src/mongo/db/commands/cpuprofile.cpp
@@ -103,7 +103,7 @@ class CpuProfilerStartCommand : public CpuProfilerCommand {
 public:
     CpuProfilerStartCommand() : CpuProfilerCommand(commandName) {}
 
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      std::string const& db,
                      BSONObj& cmdObj,
                      int options,
@@ -120,7 +120,7 @@ class CpuProfilerStopCommand : public CpuProfilerCommand {
 public:
     CpuProfilerStopCommand() : CpuProfilerCommand(commandName) {}
 
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      std::string const& db,
                      BSONObj& cmdObj,
                      int options,
@@ -133,16 +133,16 @@ public:
 char const* const CpuProfilerStartCommand::commandName = "_cpuProfilerStart";
 char const* const CpuProfilerStopCommand::commandName = "_cpuProfilerStop";
 
-bool CpuProfilerStartCommand::run(OperationContext* txn,
+bool CpuProfilerStartCommand::run(OperationContext* opCtx,
                                   std::string const& db,
                                   BSONObj& cmdObj,
                                   int options,
                                   std::string& errmsg,
                                   BSONObjBuilder& result) {
     // The DB lock here is just so we have IX on the global lock in order to prevent shutdown
-    ScopedTransaction transaction(txn, MODE_IX);
-    Lock::DBLock dbXLock(txn->lockState(), db, MODE_X);
-    OldClientContext ctx(txn, db, false /* no shard version checking */);
+    ScopedTransaction transaction(opCtx, MODE_IX);
+    Lock::DBLock dbXLock(opCtx->lockState(), db, MODE_X);
+    OldClientContext ctx(opCtx, db, false /* no shard version checking */);
 
     std::string profileFilename = cmdObj[commandName]["profileFilename"].String();
     if (!::ProfilerStart(profileFilename.c_str())) {
@@ -152,16 +152,16 @@ bool CpuProfilerStartCommand::run(OperationContext* txn,
     return true;
 }
 
-bool CpuProfilerStopCommand::run(OperationContext* txn,
+bool CpuProfilerStopCommand::run(OperationContext* opCtx,
                                  std::string const& db,
                                  BSONObj& cmdObj,
                                  int options,
                                  std::string& errmsg,
                                  BSONObjBuilder& result) {
     // The DB lock here is just so we have IX on the global lock in order to prevent shutdown
-    ScopedTransaction transaction(txn, MODE_IX);
-    Lock::DBLock dbXLock(txn->lockState(), db, MODE_X);
-    OldClientContext ctx(txn, db, false /* no shard version checking */);
+    ScopedTransaction transaction(opCtx, MODE_IX);
+    Lock::DBLock dbXLock(opCtx->lockState(), db, MODE_X);
+    OldClientContext ctx(opCtx, db, false /* no shard version checking */);
 
     ::ProfilerStop();
     return true;
diff --git a/src/mongo/db/commands/create_indexes.cpp b/src/mongo/db/commands/create_indexes.cpp
index 681370348ce..8c887502d62 100644
--- a/src/mongo/db/commands/create_indexes.cpp
+++ b/src/mongo/db/commands/create_indexes.cpp
@@ -156,12 +156,12 @@ StatusWith<std::vector<BSONObj>> parseAndValidateIndexSpecs(
  * form stored in the IndexCatalog should any of these indexes already exist.
  */
 StatusWith<std::vector<BSONObj>> resolveCollectionDefaultProperties(
-    OperationContext* txn, const Collection* collection, std::vector<BSONObj> indexSpecs) {
+    OperationContext* opCtx, const Collection* collection, std::vector<BSONObj> indexSpecs) {
     std::vector<BSONObj> indexSpecsWithDefaults = std::move(indexSpecs);
 
     for (size_t i = 0, numIndexSpecs = indexSpecsWithDefaults.size(); i < numIndexSpecs; ++i) {
         auto indexSpecStatus = index_key_validate::validateIndexSpecCollation(
-            txn, indexSpecsWithDefaults[i], collection->getDefaultCollator());
+            opCtx, indexSpecsWithDefaults[i], collection->getDefaultCollator());
         if (!indexSpecStatus.isOK()) {
             return indexSpecStatus.getStatus();
         }
@@ -171,7 +171,7 @@ StatusWith<std::vector<BSONObj>> resolveCollectionDefaultProperties(
                 indexSpec[IndexDescriptor::kKeyPatternFieldName].Obj())) {
             std::unique_ptr<CollatorInterface> indexCollator;
             if (auto collationElem = indexSpec[IndexDescriptor::kCollationFieldName]) {
-                auto collatorStatus = CollatorFactoryInterface::get(txn->getServiceContext())
+                auto collatorStatus = CollatorFactoryInterface::get(opCtx->getServiceContext())
                                           ->makeFromBSON(collationElem.Obj());
                 // validateIndexSpecCollation() should have checked that the index collation spec is
                 // valid.
@@ -225,7 +225,7 @@ public:
         return Status(ErrorCodes::Unauthorized, "Unauthorized");
     }
 
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const string& dbname,
                      BSONObj& cmdObj,
                      int options,
@@ -246,56 +246,56 @@ public:
 
         // now we know we have to create index(es)
         // Note: createIndexes command does not currently respect shard versioning.
-        ScopedTransaction transaction(txn, MODE_IX);
-        Lock::DBLock dbLock(txn->lockState(), ns.db(), MODE_X);
-        if (!repl::getGlobalReplicationCoordinator()->canAcceptWritesFor(txn, ns)) {
+        ScopedTransaction transaction(opCtx, MODE_IX);
+        Lock::DBLock dbLock(opCtx->lockState(), ns.db(), MODE_X);
+        if (!repl::getGlobalReplicationCoordinator()->canAcceptWritesFor(opCtx, ns)) {
             return appendCommandStatus(
                 result,
                 Status(ErrorCodes::NotMaster,
                        str::stream() << "Not primary while creating indexes in " << ns.ns()));
         }
 
-        Database* db = dbHolder().get(txn, ns.db());
+        Database* db = dbHolder().get(opCtx, ns.db());
         if (!db) {
-            db = dbHolder().openDb(txn, ns.db());
+            db = dbHolder().openDb(opCtx, ns.db());
         }
 
         Collection* collection = db->getCollection(ns.ns());
         if (collection) {
             result.appendBool("createdCollectionAutomatically", false);
         } else {
-            if (db->getViewCatalog()->lookup(txn, ns.ns())) {
+            if (db->getViewCatalog()->lookup(opCtx, ns.ns())) {
                 errmsg = "Cannot create indexes on a view";
                 return appendCommandStatus(result, {ErrorCodes::CommandNotSupportedOnView, errmsg});
             }
 
             MONGO_WRITE_CONFLICT_RETRY_LOOP_BEGIN {
-                WriteUnitOfWork wunit(txn);
-                collection = db->createCollection(txn, ns.ns(), CollectionOptions());
+                WriteUnitOfWork wunit(opCtx);
+                collection = db->createCollection(opCtx, ns.ns(), CollectionOptions());
                 invariant(collection);
                 wunit.commit();
             }
-            MONGO_WRITE_CONFLICT_RETRY_LOOP_END(txn, kCommandName, ns.ns());
+            MONGO_WRITE_CONFLICT_RETRY_LOOP_END(opCtx, kCommandName, ns.ns());
             result.appendBool("createdCollectionAutomatically", true);
         }
 
         auto indexSpecsWithDefaults =
-            resolveCollectionDefaultProperties(txn, collection, std::move(specs));
+            resolveCollectionDefaultProperties(opCtx, collection, std::move(specs));
         if (!indexSpecsWithDefaults.isOK()) {
             return appendCommandStatus(result, indexSpecsWithDefaults.getStatus());
         }
         specs = std::move(indexSpecsWithDefaults.getValue());
 
-        const int numIndexesBefore = collection->getIndexCatalog()->numIndexesTotal(txn);
+        const int numIndexesBefore = collection->getIndexCatalog()->numIndexesTotal(opCtx);
         result.append("numIndexesBefore", numIndexesBefore);
 
-        auto client = txn->getClient();
+        auto client = opCtx->getClient();
         ScopeGuard lastOpSetterGuard =
             MakeObjGuard(repl::ReplClientInfo::forClient(client),
                          &repl::ReplClientInfo::setLastOpToSystemLastOpTime,
-                         txn);
+                         opCtx);
 
-        MultiIndexBlock indexer(txn, collection);
+        MultiIndexBlock indexer(opCtx, collection);
         indexer.allowBackgroundBuilding();
         indexer.allowInterruption();
 
@@ -315,7 +315,7 @@ public:
         for (size_t i = 0; i < specs.size(); i++) {
             const BSONObj& spec = specs[i];
             if (spec["unique"].trueValue()) {
-                status = checkUniqueIndexConstraints(txn, ns.ns(), spec["key"].Obj());
+                status = checkUniqueIndexConstraints(opCtx, ns.ns(), spec["key"].Obj());
 
                 if (!status.isOK()) {
                     return appendCommandStatus(result, status);
@@ -327,14 +327,14 @@ public:
         MONGO_WRITE_CONFLICT_RETRY_LOOP_BEGIN {
             indexInfoObjs = uassertStatusOK(indexer.init(specs));
         }
-        MONGO_WRITE_CONFLICT_RETRY_LOOP_END(txn, kCommandName, ns.ns());
+        MONGO_WRITE_CONFLICT_RETRY_LOOP_END(opCtx, kCommandName, ns.ns());
 
         // If we're a background index, replace exclusive db lock with an intent lock, so that
         // other readers and writers can proceed during this phase.
         if (indexer.getBuildInBackground()) {
-            txn->recoveryUnit()->abandonSnapshot();
+            opCtx->recoveryUnit()->abandonSnapshot();
             dbLock.relockWithMode(MODE_IX);
-            if (!repl::getGlobalReplicationCoordinator()->canAcceptWritesFor(txn, ns)) {
+            if (!repl::getGlobalReplicationCoordinator()->canAcceptWritesFor(opCtx, ns)) {
                 return appendCommandStatus(
                     result,
                     Status(ErrorCodes::NotMaster,
@@ -344,7 +344,7 @@ public:
         }
 
         try {
-            Lock::CollectionLock colLock(txn->lockState(), ns.ns(), MODE_IX);
+            Lock::CollectionLock colLock(opCtx->lockState(), ns.ns(), MODE_IX);
             uassertStatusOK(indexer.insertAllDocumentsInCollection());
         } catch (const DBException& e) {
             invariant(e.getCode() != ErrorCodes::WriteConflict);
@@ -354,9 +354,9 @@ public:
                 try {
                     // This function cannot throw today, but we will preemptively prepare for
                     // that day, to avoid data corruption due to lack of index cleanup.
-                    txn->recoveryUnit()->abandonSnapshot();
+                    opCtx->recoveryUnit()->abandonSnapshot();
                     dbLock.relockWithMode(MODE_X);
-                    if (!repl::getGlobalReplicationCoordinator()->canAcceptWritesFor(txn, ns)) {
+                    if (!repl::getGlobalReplicationCoordinator()->canAcceptWritesFor(opCtx, ns)) {
                         return appendCommandStatus(
                             result,
                             Status(ErrorCodes::NotMaster,
@@ -374,33 +374,33 @@ public:
         }
         // Need to return db lock back to exclusive, to complete the index build.
         if (indexer.getBuildInBackground()) {
-            txn->recoveryUnit()->abandonSnapshot();
+            opCtx->recoveryUnit()->abandonSnapshot();
             dbLock.relockWithMode(MODE_X);
             uassert(ErrorCodes::NotMaster,
                     str::stream() << "Not primary while completing index build in " << dbname,
-                    repl::getGlobalReplicationCoordinator()->canAcceptWritesFor(txn, ns));
+                    repl::getGlobalReplicationCoordinator()->canAcceptWritesFor(opCtx, ns));
 
-            Database* db = dbHolder().get(txn, ns.db());
+            Database* db = dbHolder().get(opCtx, ns.db());
             uassert(28551, "database dropped during index build", db);
             uassert(28552, "collection dropped during index build", db->getCollection(ns.ns()));
         }
 
         MONGO_WRITE_CONFLICT_RETRY_LOOP_BEGIN {
-            WriteUnitOfWork wunit(txn);
+            WriteUnitOfWork wunit(opCtx);
 
             indexer.commit();
 
             for (auto&& infoObj : indexInfoObjs) {
                 std::string systemIndexes = ns.getSystemIndexesCollection();
                 getGlobalServiceContext()->getOpObserver()->onCreateIndex(
-                    txn, systemIndexes, infoObj, false);
+                    opCtx, systemIndexes, infoObj, false);
             }
 
             wunit.commit();
         }
-        MONGO_WRITE_CONFLICT_RETRY_LOOP_END(txn, kCommandName, ns.ns());
+        MONGO_WRITE_CONFLICT_RETRY_LOOP_END(opCtx, kCommandName, ns.ns());
 
-        result.append("numIndexesAfter", collection->getIndexCatalog()->numIndexesTotal(txn));
+        result.append("numIndexesAfter", collection->getIndexCatalog()->numIndexesTotal(opCtx));
 
         lastOpSetterGuard.Dismiss();
 
@@ -408,12 +408,12 @@ public:
     }
 
 private:
-    static Status checkUniqueIndexConstraints(OperationContext* txn,
+    static Status checkUniqueIndexConstraints(OperationContext* opCtx,
                                               StringData ns,
                                               const BSONObj& newIdxKey) {
-        invariant(txn->lockState()->isCollectionLockedForMode(ns, MODE_X));
+        invariant(opCtx->lockState()->isCollectionLockedForMode(ns, MODE_X));
 
-        auto metadata(CollectionShardingState::get(txn, ns.toString())->getMetadata());
+        auto metadata(CollectionShardingState::get(opCtx, ns.toString())->getMetadata());
         if (metadata) {
             ShardKeyPattern shardKeyPattern(metadata->getKeyPattern());
             if (!shardKeyPattern.isUniqueIndexCompatible(newIdxKey)) {
diff --git a/src/mongo/db/commands/current_op.cpp b/src/mongo/db/commands/current_op.cpp
index c696533ef7a..c5f05e314ae 100644
--- a/src/mongo/db/commands/current_op.cpp
+++ b/src/mongo/db/commands/current_op.cpp
@@ -85,7 +85,7 @@ public:
         return Status(ErrorCodes::Unauthorized, "Unauthorized");
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const std::string& db,
              BSONObj& cmdObj,
              int options,
@@ -117,14 +117,14 @@ public:
         std::vector<BSONObj> inprogInfos;
         BSONArrayBuilder inprogBuilder(result.subarrayStart("inprog"));
 
-        for (ServiceContext::LockedClientsCursor cursor(txn->getClient()->getServiceContext());
+        for (ServiceContext::LockedClientsCursor cursor(opCtx->getClient()->getServiceContext());
              Client* client = cursor.next();) {
             invariant(client);
 
             stdx::lock_guard<Client> lk(*client);
 
             if (ownOpsOnly &&
-                !AuthorizationSession::get(txn->getClient())->isCoauthorizedWithClient(client)) {
+                !AuthorizationSession::get(opCtx->getClient())->isCoauthorizedWithClient(client)) {
                 continue;
             }
 
@@ -183,7 +183,7 @@ public:
             // don't have a collection, we pass in a fake collection name (and this is okay,
             // because $where parsing only relies on the database part of the namespace).
             const NamespaceString fakeNS(db, "$dummyNamespaceForCurrop");
-            const Matcher matcher(filter, ExtensionsCallbackReal(txn, &fakeNS), nullptr);
+            const Matcher matcher(filter, ExtensionsCallbackReal(opCtx, &fakeNS), nullptr);
 
             for (const auto& info : inprogInfos) {
                 if (matcher.matches(info)) {
diff --git a/src/mongo/db/commands/dbcommands.cpp b/src/mongo/db/commands/dbcommands.cpp
index 9ba85e79f9f..7b4879425a3 100644
--- a/src/mongo/db/commands/dbcommands.cpp
+++ b/src/mongo/db/commands/dbcommands.cpp
@@ -121,8 +121,8 @@ using std::stringstream;
 using std::unique_ptr;
 
 namespace {
-void registerErrorImpl(OperationContext* txn, const DBException& exception) {
-    CurOp::get(txn)->debug().exceptionInfo = exception.getInfo();
+void registerErrorImpl(OperationContext* opCtx, const DBException& exception) {
+    CurOp::get(opCtx)->debug().exceptionInfo = exception.getInfo();
 }
 
 MONGO_INITIALIZER(InitializeRegisterErrorHandler)(InitializerContext* const) {
@@ -130,18 +130,18 @@ MONGO_INITIALIZER(InitializeRegisterErrorHandler)(InitializerContext* const) {
     return Status::OK();
 }
 /**
- * For replica set members it returns the last known op time from txn. Otherwise will return
+ * For replica set members it returns the last known op time from opCtx. Otherwise will return
  * uninitialized logical time.
  */
-LogicalTime _getClientOperationTime(OperationContext* txn) {
+LogicalTime _getClientOperationTime(OperationContext* opCtx) {
     repl::ReplicationCoordinator* replCoord =
-        repl::ReplicationCoordinator::get(txn->getClient()->getServiceContext());
+        repl::ReplicationCoordinator::get(opCtx->getClient()->getServiceContext());
     const bool isReplSet =
         replCoord->getReplicationMode() == repl::ReplicationCoordinator::modeReplSet;
     LogicalTime operationTime;
     if (isReplSet) {
         operationTime = LogicalTime(
-            repl::ReplClientInfo::forClient(txn->getClient()).getLastOp().getTimestamp());
+            repl::ReplClientInfo::forClient(opCtx->getClient()).getLastOp().getTimestamp());
     }
     return operationTime;
 }
@@ -159,7 +159,7 @@ public:
              << "N to wait N seconds for other members to catch up.";
     }
 
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const string& dbname,
                      BSONObj& cmdObj,
                      int options,
@@ -173,7 +173,7 @@ public:
         }
 
         Status status = repl::getGlobalReplicationCoordinator()->stepDown(
-            txn, force, Seconds(timeoutSecs), Seconds(120));
+            opCtx, force, Seconds(timeoutSecs), Seconds(120));
         if (!status.isOK() && status.code() != ErrorCodes::NotMaster) {  // ignore not master
             return appendCommandStatus(result, status);
         }
@@ -209,7 +209,7 @@ public:
 
     CmdDropDatabase() : Command("dropDatabase") {}
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int,
@@ -239,7 +239,7 @@ public:
                 result, Status(ErrorCodes::IllegalOperation, "have to pass 1 as db parameter"));
         }
 
-        Status status = dropDatabase(txn, dbname);
+        Status status = dropDatabase(opCtx, dbname);
         if (status == ErrorCodes::NamespaceNotFound) {
             return appendCommandStatus(result, Status::OK());
         }
@@ -278,7 +278,7 @@ public:
 
     CmdRepairDatabase() : Command("repairDatabase") {}
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int,
@@ -291,9 +291,9 @@ public:
         }
 
         // Closing a database requires a global lock.
-        ScopedTransaction transaction(txn, MODE_X);
-        Lock::GlobalWrite lk(txn->lockState());
-        if (!dbHolder().get(txn, dbname)) {
+        ScopedTransaction transaction(opCtx, MODE_X);
+        Lock::GlobalWrite lk(opCtx->lockState());
+        if (!dbHolder().get(opCtx, dbname)) {
             // If the name doesn't make an exact match, check for a case insensitive match.
             std::set<std::string> otherCasing = dbHolder().getNamesWithConflictingCasing(dbname);
             if (otherCasing.empty()) {
@@ -310,9 +310,9 @@ public:
 
         // TODO (Kal): OldClientContext legacy, needs to be removed
         {
-            CurOp::get(txn)->ensureStarted();
-            stdx::lock_guard<Client> lk(*txn->getClient());
-            CurOp::get(txn)->setNS_inlock(dbname);
+            CurOp::get(opCtx)->ensureStarted();
+            stdx::lock_guard<Client> lk(*opCtx->getClient());
+            CurOp::get(opCtx)->setNS_inlock(dbname);
         }
 
         log() << "repairDatabase " << dbname;
@@ -324,14 +324,14 @@ public:
         bool backupOriginalFiles = e.isBoolean() && e.boolean();
 
         StorageEngine* engine = getGlobalServiceContext()->getGlobalStorageEngine();
-        bool shouldReplicateWrites = txn->writesAreReplicated();
-        txn->setReplicatedWrites(false);
-        ON_BLOCK_EXIT(&OperationContext::setReplicatedWrites, txn, shouldReplicateWrites);
-        Status status =
-            repairDatabase(txn, engine, dbname, preserveClonedFilesOnFailure, backupOriginalFiles);
+        bool shouldReplicateWrites = opCtx->writesAreReplicated();
+        opCtx->setReplicatedWrites(false);
+        ON_BLOCK_EXIT(&OperationContext::setReplicatedWrites, opCtx, shouldReplicateWrites);
+        Status status = repairDatabase(
+            opCtx, engine, dbname, preserveClonedFilesOnFailure, backupOriginalFiles);
 
         // Open database before returning
-        dbHolder().openDb(txn, dbname);
+        dbHolder().openDb(opCtx, dbname);
         return appendCommandStatus(result, status);
     }
 } cmdRepairDatabase;
@@ -385,7 +385,7 @@ public:
 
     CmdProfile() : Command("profile") {}
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int options,
@@ -403,8 +403,8 @@ public:
 
         Status status = Status::OK();
 
-        ScopedTransaction transaction(txn, transactionMode);
-        AutoGetDb ctx(txn, dbname, dbMode);
+        ScopedTransaction transaction(opCtx, transactionMode);
+        AutoGetDb ctx(opCtx, dbname, dbMode);
         Database* db = ctx.getDb();
 
         result.append("was", db ? db->getProfilingLevel() : serverGlobalParams.defaultProfile);
@@ -415,9 +415,9 @@ public:
             if (!db) {
                 // When setting the profiling level, create the database if it didn't already exist.
                 // When just reading the profiling level, we do not create the database.
-                db = dbHolder().openDb(txn, dbname);
+                db = dbHolder().openDb(opCtx, dbname);
             }
-            status = db->setProfilingLevel(txn, profilingLevel);
+            status = db->setProfilingLevel(opCtx, profilingLevel);
         }
 
         const BSONElement slow = cmdObj["slowms"];
@@ -470,7 +470,7 @@ public:
         out->push_back(Privilege(ResourcePattern::forClusterResource(), actions));
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int,
@@ -483,14 +483,14 @@ public:
         // This doesn't look like it requires exclusive DB lock, because it uses its own diag
         // locking, but originally the lock was set to be WRITE, so preserving the behaviour.
         //
-        ScopedTransaction transaction(txn, MODE_IX);
-        Lock::DBLock dbXLock(txn->lockState(), dbname, MODE_X);
+        ScopedTransaction transaction(opCtx, MODE_IX);
+        Lock::DBLock dbXLock(opCtx->lockState(), dbname, MODE_X);
 
         // TODO (Kal): OldClientContext legacy, needs to be removed
         {
-            CurOp::get(txn)->ensureStarted();
-            stdx::lock_guard<Client> lk(*txn->getClient());
-            CurOp::get(txn)->setNS_inlock(dbname);
+            CurOp::get(opCtx)->ensureStarted();
+            stdx::lock_guard<Client> lk(*opCtx->getClient());
+            CurOp::get(opCtx)->setNS_inlock(dbname);
         }
 
         int was = _diaglog.setLevel(cmdObj.firstElement().numberInt());
@@ -530,7 +530,7 @@ public:
         return true;
     }
 
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const string& dbname,
                      BSONObj& cmdObj,
                      int,
@@ -550,7 +550,7 @@ public:
             return false;
         }
 
-        return appendCommandStatus(result, dropCollection(txn, nsToDrop, result));
+        return appendCommandStatus(result, dropCollection(opCtx, nsToDrop, result));
     }
 
 } cmdDrop;
@@ -582,7 +582,7 @@ public:
         return AuthorizationSession::get(client)->checkAuthForCreate(nss, cmdObj);
     }
 
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const string& dbname,
                      BSONObj& cmdObj,
                      int,
@@ -649,7 +649,7 @@ public:
                         {ErrorCodes::TypeMismatch,
                          str::stream() << "'collation' has to be a document: " << collationElem});
                 }
-                auto collatorStatus = CollatorFactoryInterface::get(txn->getServiceContext())
+                auto collatorStatus = CollatorFactoryInterface::get(opCtx->getServiceContext())
                                           ->makeFromBSON(collationElem.Obj());
                 if (!collatorStatus.isOK()) {
                     return appendCommandStatus(result, collatorStatus.getStatus());
@@ -657,10 +657,10 @@ public:
                 defaultCollator = std::move(collatorStatus.getValue());
             }
             idIndexSpec = uassertStatusOK(index_key_validate::validateIndexSpecCollation(
-                txn, idIndexSpec, defaultCollator.get()));
+                opCtx, idIndexSpec, defaultCollator.get()));
             std::unique_ptr<CollatorInterface> idIndexCollator;
             if (auto collationElem = idIndexSpec["collation"]) {
-                auto collatorStatus = CollatorFactoryInterface::get(txn->getServiceContext())
+                auto collatorStatus = CollatorFactoryInterface::get(opCtx->getServiceContext())
                                           ->makeFromBSON(collationElem.Obj());
                 // validateIndexSpecCollation() should have checked that the _id index collation
                 // spec is valid.
@@ -677,12 +677,12 @@ public:
             // Remove "idIndex" field from command.
             auto resolvedCmdObj = cmdObj.removeField("idIndex");
 
-            return appendCommandStatus(result,
-                                       createCollection(txn, dbname, resolvedCmdObj, idIndexSpec));
+            return appendCommandStatus(
+                result, createCollection(opCtx, dbname, resolvedCmdObj, idIndexSpec));
         }
 
         BSONObj idIndexSpec;
-        return appendCommandStatus(result, createCollection(txn, dbname, cmdObj, idIndexSpec));
+        return appendCommandStatus(result, createCollection(opCtx, dbname, cmdObj, idIndexSpec));
     }
 } cmdCreate;
 
@@ -724,7 +724,7 @@ public:
         out->push_back(Privilege(parseResourcePattern(dbname, cmdObj), ActionType::find));
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& jsobj,
              int,
@@ -763,7 +763,7 @@ public:
             qr->setSort(sort);
 
             auto statusWithCQ = CanonicalQuery::canonicalize(
-                txn, std::move(qr), ExtensionsCallbackDisallowExtensions());
+                opCtx, std::move(qr), ExtensionsCallbackDisallowExtensions());
             if (!statusWithCQ.isOK()) {
                 uasserted(17240, "Can't canonicalize query " + query.toString());
                 return 0;
@@ -773,10 +773,10 @@ public:
             // Check shard version at startup.
             // This will throw before we've done any work if shard version is outdated
             // We drop and re-acquire these locks every document because md5'ing is expensive
-            unique_ptr<AutoGetCollectionForRead> ctx(new AutoGetCollectionForRead(txn, nss));
+            unique_ptr<AutoGetCollectionForRead> ctx(new AutoGetCollectionForRead(opCtx, nss));
             Collection* coll = ctx->getCollection();
 
-            auto statusWithPlanExecutor = getExecutor(txn,
+            auto statusWithPlanExecutor = getExecutor(opCtx,
                                                       coll,
                                                       std::move(cq),
                                                       PlanExecutor::YIELD_MANUAL,
@@ -801,7 +801,7 @@ public:
                         break;  // skipped chunk is probably on another shard
                     }
                     log() << "should have chunk: " << n << " have:" << myn;
-                    dumpChunks(txn, nss.ns(), query, sort);
+                    dumpChunks(opCtx, nss.ns(), query, sort);
                     uassert(10040, "chunks out of order", n == myn);
                 }
 
@@ -819,7 +819,7 @@ public:
 
                 try {
                     // RELOCKED
-                    ctx.reset(new AutoGetCollectionForRead(txn, nss));
+                    ctx.reset(new AutoGetCollectionForRead(opCtx, nss));
                 } catch (const SendStaleConfigException& ex) {
                     LOG(1) << "chunk metadata changed during filemd5, will retarget and continue";
                     break;
@@ -850,15 +850,15 @@ public:
             result.append("numChunks", n);
             result.append("md5", digestToString(d));
         }
-        MONGO_WRITE_CONFLICT_RETRY_LOOP_END(txn, "filemd5", dbname);
+        MONGO_WRITE_CONFLICT_RETRY_LOOP_END(opCtx, "filemd5", dbname);
         return true;
     }
 
-    void dumpChunks(OperationContext* txn,
+    void dumpChunks(OperationContext* opCtx,
                     const string& ns,
                     const BSONObj& query,
                     const BSONObj& sort) {
-        DBDirectClient client(txn);
+        DBDirectClient client(opCtx);
         Query q(query);
         q.sort(sort);
         unique_ptr<DBClientCursor> c = client.query(ns, q);
@@ -905,7 +905,7 @@ public:
         out->push_back(Privilege(parseResourcePattern(dbname, cmdObj), actions));
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& jsobj,
              int,
@@ -919,12 +919,12 @@ public:
         BSONObj keyPattern = jsobj.getObjectField("keyPattern");
         bool estimate = jsobj["estimate"].trueValue();
 
-        AutoGetCollectionForRead ctx(txn, NamespaceString(ns));
+        AutoGetCollectionForRead ctx(opCtx, NamespaceString(ns));
 
         Collection* collection = ctx.getCollection();
         long long numRecords = 0;
         if (collection) {
-            numRecords = collection->numRecords(txn);
+            numRecords = collection->numRecords(opCtx);
         }
 
         if (numRecords == 0) {
@@ -939,12 +939,13 @@ public:
         unique_ptr<PlanExecutor> exec;
         if (min.isEmpty() && max.isEmpty()) {
             if (estimate) {
-                result.appendNumber("size", static_cast<long long>(collection->dataSize(txn)));
+                result.appendNumber("size", static_cast<long long>(collection->dataSize(opCtx)));
                 result.appendNumber("numObjects", numRecords);
                 result.append("millis", timer.millis());
                 return 1;
             }
-            exec = InternalPlanner::collectionScan(txn, ns, collection, PlanExecutor::YIELD_MANUAL);
+            exec =
+                InternalPlanner::collectionScan(opCtx, ns, collection, PlanExecutor::YIELD_MANUAL);
         } else if (min.isEmpty() || max.isEmpty()) {
             errmsg = "only one of min or max specified";
             return false;
@@ -955,7 +956,7 @@ public:
             }
 
             IndexDescriptor* idx =
-                collection->getIndexCatalog()->findShardKeyPrefixedIndex(txn,
+                collection->getIndexCatalog()->findShardKeyPrefixedIndex(opCtx,
                                                                          keyPattern,
                                                                          true);  // requireSingleKey
 
@@ -968,7 +969,7 @@ public:
             min = Helpers::toKeyFormat(kp.extendRangeBound(min, false));
             max = Helpers::toKeyFormat(kp.extendRangeBound(max, false));
 
-            exec = InternalPlanner::indexScan(txn,
+            exec = InternalPlanner::indexScan(opCtx,
                                               collection,
                                               idx,
                                               min,
@@ -977,7 +978,7 @@ public:
                                               PlanExecutor::YIELD_MANUAL);
         }
 
-        long long avgObjSize = collection->dataSize(txn) / numRecords;
+        long long avgObjSize = collection->dataSize(opCtx) / numRecords;
 
         long long maxSize = jsobj["maxSize"].numberLong();
         long long maxObjects = jsobj["maxObjects"].numberLong();
@@ -992,7 +993,7 @@ public:
             if (estimate)
                 size += avgObjSize;
             else
-                size += collection->getRecordStore()->dataFor(txn, loc).size();
+                size += collection->getRecordStore()->dataFor(opCtx, loc).size();
 
             numObjects++;
 
@@ -1049,7 +1050,7 @@ public:
         out->push_back(Privilege(parseResourcePattern(dbname, cmdObj), actions));
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& jsobj,
              int,
@@ -1063,7 +1064,7 @@ public:
         }
 
         result.append("ns", nss.ns());
-        Status status = appendCollectionStorageStats(txn, nss, jsobj, &result);
+        Status status = appendCollectionStorageStats(opCtx, nss, jsobj, &result);
         if (!status.isOK()) {
             errmsg = status.reason();
             return false;
@@ -1098,14 +1099,14 @@ public:
         return AuthorizationSession::get(client)->checkAuthForCollMod(nss, cmdObj);
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& jsobj,
              int,
              string& errmsg,
              BSONObjBuilder& result) {
         const NamespaceString nss(parseNsCollectionRequired(dbname, jsobj));
-        return appendCommandStatus(result, collMod(txn, nss, jsobj, &result));
+        return appendCommandStatus(result, collMod(opCtx, nss, jsobj, &result));
     }
 
 } collectionModCommand;
@@ -1134,7 +1135,7 @@ public:
         out->push_back(Privilege(ResourcePattern::forDatabaseName(dbname), actions));
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& jsobj,
              int,
@@ -1159,16 +1160,16 @@ public:
 
         // TODO (Kal): OldClientContext legacy, needs to be removed
         {
-            CurOp::get(txn)->ensureStarted();
-            stdx::lock_guard<Client> lk(*txn->getClient());
-            CurOp::get(txn)->setNS_inlock(dbname);
+            CurOp::get(opCtx)->ensureStarted();
+            stdx::lock_guard<Client> lk(*opCtx->getClient());
+            CurOp::get(opCtx)->setNS_inlock(dbname);
         }
 
         // We lock the entire database in S-mode in order to ensure that the contents will not
         // change for the stats snapshot. This might be unnecessary and if it becomes a
         // performance issue, we can take IS lock and then lock collection-by-collection.
-        ScopedTransaction scopedXact(txn, MODE_IS);
-        AutoGetDb autoDb(txn, ns, MODE_S);
+        ScopedTransaction scopedXact(opCtx, MODE_IS);
+        AutoGetDb autoDb(opCtx, ns, MODE_S);
 
         result.append("db", ns);
 
@@ -1191,12 +1192,12 @@ public:
             result.appendNumber("fileSize", 0);
         } else {
             {
-                stdx::lock_guard<Client> lk(*txn->getClient());
+                stdx::lock_guard<Client> lk(*opCtx->getClient());
                 // TODO: OldClientContext legacy, needs to be removed
-                CurOp::get(txn)->enter_inlock(dbname.c_str(), db->getProfilingLevel());
+                CurOp::get(opCtx)->enter_inlock(dbname.c_str(), db->getProfilingLevel());
             }
 
-            db->getStats(txn, &result, scale);
+            db->getStats(opCtx, &result, scale);
         }
 
         return true;
@@ -1220,13 +1221,13 @@ public:
     virtual void addRequiredPrivileges(const std::string& dbname,
                                        const BSONObj& cmdObj,
                                        std::vector<Privilege>* out) {}  // No auth required
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const string& dbname,
                      BSONObj& cmdObj,
                      int,
                      string& errmsg,
                      BSONObjBuilder& result) {
-        result << "you" << txn->getClient()->clientAddress(true /*includePort*/);
+        result << "you" << opCtx->getClient()->clientAddress(true /*includePort*/);
         return true;
     }
 } cmdWhatsMyUri;
@@ -1247,7 +1248,7 @@ public:
         return Status::OK();
     }
 
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const string& dbname,
                      BSONObj& cmdObj,
                      int,
@@ -1299,10 +1300,10 @@ const std::array<StringData, 4> neededFieldNames{QueryRequest::cmdOptionMaxTimeM
                                                  QueryRequest::queryOptionMaxTimeMS};
 }  // namespace
 
-void appendOpTimeMetadata(OperationContext* txn,
+void appendOpTimeMetadata(OperationContext* opCtx,
                           const rpc::RequestInterface& request,
                           BSONObjBuilder* metadataBob) {
-    const bool isShardingAware = ShardingState::get(txn)->enabled();
+    const bool isShardingAware = ShardingState::get(opCtx)->enabled();
     const bool isConfig = serverGlobalParams.clusterRole == ClusterRole::ConfigServer;
     repl::ReplicationCoordinator* replCoord = repl::getGlobalReplicationCoordinator();
     const bool isReplSet =
@@ -1311,7 +1312,7 @@ void appendOpTimeMetadata(OperationContext* txn,
     if (isReplSet) {
         // Attach our own last opTime.
         repl::OpTime lastOpTimeFromClient =
-            repl::ReplClientInfo::forClient(txn->getClient()).getLastOp();
+            repl::ReplClientInfo::forClient(opCtx->getClient()).getLastOp();
         replCoord->prepareReplMetadata(request.getMetadata(), lastOpTimeFromClient, metadataBob);
         // For commands from mongos, append some info to help getLastError(w) work.
         // TODO: refactor out of here as part of SERVER-18236
@@ -1329,11 +1330,11 @@ void appendOpTimeMetadata(OperationContext* txn,
 }
 
 namespace {
-void execCommandHandler(OperationContext* const txn,
+void execCommandHandler(OperationContext* const opCtx,
                         Command* const command,
                         const rpc::RequestInterface& request,
                         rpc::ReplyBuilderInterface* const replyBuilder) {
-    mongo::execCommandDatabase(txn, command, request, replyBuilder);
+    mongo::execCommandDatabase(opCtx, command, request, replyBuilder);
 }
 
 MONGO_INITIALIZER(InitializeCommandExecCommandHandler)(InitializerContext* const) {
@@ -1346,7 +1347,7 @@ MONGO_INITIALIZER(InitializeCommandExecCommandHandler)(InitializerContext* const
 // use shardingState and the repl coordinator without changing our entire library
 // structure.
 // It will be moved back as part of SERVER-18236.
-bool Command::run(OperationContext* txn,
+bool Command::run(OperationContext* opCtx,
                   const rpc::RequestInterface& request,
                   rpc::ReplyBuilderInterface* replyBuilder) {
     auto bytesToReserve = reserveBytesForReply();
@@ -1366,7 +1367,7 @@ bool Command::run(OperationContext* txn,
     const std::string db = request.getDatabase().toString();
 
     BSONObjBuilder inPlaceReplyBob(replyBuilder->getInPlaceReplyBuilder(bytesToReserve));
-    auto readConcernArgsStatus = extractReadConcern(txn, cmd, supportsReadConcern());
+    auto readConcernArgsStatus = extractReadConcern(opCtx, cmd, supportsReadConcern());
 
     if (!readConcernArgsStatus.isOK()) {
         auto result = appendCommandStatus(inPlaceReplyBob, readConcernArgsStatus.getStatus());
@@ -1375,7 +1376,7 @@ bool Command::run(OperationContext* txn,
         return result;
     }
 
-    Status rcStatus = waitForReadConcern(txn, readConcernArgsStatus.getValue());
+    Status rcStatus = waitForReadConcern(opCtx, readConcernArgsStatus.getValue());
     if (!rcStatus.isOK()) {
         if (rcStatus == ErrorCodes::ExceededTimeLimit) {
             const int debugLevel =
@@ -1393,7 +1394,7 @@ bool Command::run(OperationContext* txn,
 
     std::string errmsg;
     bool result;
-    auto startOperationTime = _getClientOperationTime(txn);
+    auto startOperationTime = _getClientOperationTime(opCtx);
     if (!supportsWriteConcern(cmd)) {
         if (commandSpecifiesWriteConcern(cmd)) {
             auto result = appendCommandStatus(
@@ -1405,9 +1406,9 @@ bool Command::run(OperationContext* txn,
         }
 
         // TODO: remove queryOptions parameter from command's run method.
-        result = run(txn, db, cmd, 0, errmsg, inPlaceReplyBob);
+        result = run(opCtx, db, cmd, 0, errmsg, inPlaceReplyBob);
     } else {
-        auto wcResult = extractWriteConcern(txn, cmd, db);
+        auto wcResult = extractWriteConcern(opCtx, cmd, db);
         if (!wcResult.isOK()) {
             auto result = appendCommandStatus(inPlaceReplyBob, wcResult.getStatus());
             inPlaceReplyBob.doneFast();
@@ -1416,20 +1417,20 @@ bool Command::run(OperationContext* txn,
         }
 
         // Change the write concern while running the command.
-        const auto oldWC = txn->getWriteConcern();
-        ON_BLOCK_EXIT([&] { txn->setWriteConcern(oldWC); });
-        txn->setWriteConcern(wcResult.getValue());
+        const auto oldWC = opCtx->getWriteConcern();
+        ON_BLOCK_EXIT([&] { opCtx->setWriteConcern(oldWC); });
+        opCtx->setWriteConcern(wcResult.getValue());
 
-        result = run(txn, db, cmd, 0, errmsg, inPlaceReplyBob);
+        result = run(opCtx, db, cmd, 0, errmsg, inPlaceReplyBob);
 
         // Nothing in run() should change the writeConcern.
-        dassert(SimpleBSONObjComparator::kInstance.evaluate(txn->getWriteConcern().toBSON() ==
+        dassert(SimpleBSONObjComparator::kInstance.evaluate(opCtx->getWriteConcern().toBSON() ==
                                                             wcResult.getValue().toBSON()));
 
         WriteConcernResult res;
         auto waitForWCStatus =
-            waitForWriteConcern(txn,
-                                repl::ReplClientInfo::forClient(txn->getClient()).getLastOp(),
+            waitForWriteConcern(opCtx,
+                                repl::ReplClientInfo::forClient(opCtx->getClient()).getLastOp(),
                                 wcResult.getValue(),
                                 &res);
         appendCommandWCStatus(inPlaceReplyBob, waitForWCStatus, res);
@@ -1450,7 +1451,7 @@ bool Command::run(OperationContext* txn,
                                   repl::ReadConcernLevel::kLinearizableReadConcern) &&
         (request.getCommandName() != "getMore")) {
 
-        auto linearizableReadStatus = waitForLinearizableReadConcern(txn);
+        auto linearizableReadStatus = waitForLinearizableReadConcern(opCtx);
 
         if (!linearizableReadStatus.isOK()) {
             inPlaceReplyBob.resetToEmpty();
@@ -1463,14 +1464,14 @@ bool Command::run(OperationContext* txn,
 
     appendCommandStatus(inPlaceReplyBob, result, errmsg);
 
-    auto finishOperationTime = _getClientOperationTime(txn);
+    auto finishOperationTime = _getClientOperationTime(opCtx);
     auto operationTime = finishOperationTime;
     invariant(finishOperationTime >= startOperationTime);
 
     // this command did not write, so return current clusterTime.
     if (finishOperationTime == startOperationTime) {
         // TODO: SERVER-27786 to return the clusterTime of the read.
-        operationTime = LogicalClock::get(txn)->getClusterTime().getTime();
+        operationTime = LogicalClock::get(opCtx)->getClusterTime().getTime();
     }
 
     appendOperationTime(inPlaceReplyBob, operationTime);
@@ -1478,7 +1479,7 @@ bool Command::run(OperationContext* txn,
     inPlaceReplyBob.doneFast();
 
     BSONObjBuilder metadataBob;
-    appendOpTimeMetadata(txn, request, &metadataBob);
+    appendOpTimeMetadata(opCtx, request, &metadataBob);
     replyBuilder->setMetadata(metadataBob.done());
 
     return result;
@@ -1495,20 +1496,20 @@ bool Command::run(OperationContext* txn,
  - context
  then calls run()
  */
-void mongo::execCommandDatabase(OperationContext* txn,
+void mongo::execCommandDatabase(OperationContext* opCtx,
                                 Command* command,
                                 const rpc::RequestInterface& request,
                                 rpc::ReplyBuilderInterface* replyBuilder) {
     try {
         {
-            stdx::lock_guard<Client> lk(*txn->getClient());
-            CurOp::get(txn)->setCommand_inlock(command);
+            stdx::lock_guard<Client> lk(*opCtx->getClient());
+            CurOp::get(opCtx)->setCommand_inlock(command);
         }
 
         // TODO: move this back to runCommands when mongos supports OperationContext
         // see SERVER-18515 for details.
-        uassertStatusOK(rpc::readRequestMetadata(txn, request.getMetadata()));
-        rpc::TrackingMetadata::get(txn).initWithOperName(command->getName());
+        uassertStatusOK(rpc::readRequestMetadata(opCtx, request.getMetadata()));
+        rpc::TrackingMetadata::get(opCtx).initWithOperName(command->getName());
 
         dassert(replyBuilder->getState() == rpc::ReplyBuilderInterface::State::kCommandReply);
 
@@ -1520,30 +1521,30 @@ void mongo::execCommandDatabase(OperationContext* txn,
         request.getCommandArgs().getFields(neededFieldNames, &extractedFields);
 
         if (Command::isHelpRequest(extractedFields[kHelpField])) {
-            CurOp::get(txn)->ensureStarted();
+            CurOp::get(opCtx)->ensureStarted();
             // We disable last-error for help requests due to SERVER-11492, because config servers
             // use help requests to determine which commands are database writes, and so must be
             // forwarded to all config servers.
-            LastError::get(txn->getClient()).disable();
-            Command::generateHelpResponse(txn, request, replyBuilder, *command);
+            LastError::get(opCtx->getClient()).disable();
+            Command::generateHelpResponse(opCtx, request, replyBuilder, *command);
             return;
         }
 
-        ImpersonationSessionGuard guard(txn);
+        ImpersonationSessionGuard guard(opCtx);
         uassertStatusOK(
-            Command::checkAuthorization(command, txn, dbname, request.getCommandArgs()));
+            Command::checkAuthorization(command, opCtx, dbname, request.getCommandArgs()));
 
         repl::ReplicationCoordinator* replCoord =
-            repl::ReplicationCoordinator::get(txn->getClient()->getServiceContext());
-        const bool iAmPrimary = replCoord->canAcceptWritesForDatabase_UNSAFE(txn, dbname);
+            repl::ReplicationCoordinator::get(opCtx->getClient()->getServiceContext());
+        const bool iAmPrimary = replCoord->canAcceptWritesForDatabase_UNSAFE(opCtx, dbname);
 
         {
             bool commandCanRunOnSecondary = command->slaveOk();
 
             bool commandIsOverriddenToRunOnSecondary = command->slaveOverrideOk() &&
-                rpc::ServerSelectionMetadata::get(txn).canRunOnSecondary();
+                rpc::ServerSelectionMetadata::get(opCtx).canRunOnSecondary();
 
-            bool iAmStandalone = !txn->writesAreReplicated();
+            bool iAmStandalone = !opCtx->writesAreReplicated();
             bool canRunHere = iAmPrimary || commandCanRunOnSecondary ||
                 commandIsOverriddenToRunOnSecondary || iAmStandalone;
 
@@ -1556,7 +1557,7 @@ void mongo::execCommandDatabase(OperationContext* txn,
 
             if (!command->maintenanceOk() &&
                 replCoord->getReplicationMode() == repl::ReplicationCoordinator::modeReplSet &&
-                !replCoord->canAcceptWritesForDatabase_UNSAFE(txn, dbname) &&
+                !replCoord->canAcceptWritesForDatabase_UNSAFE(opCtx, dbname) &&
                 !replCoord->getMemberState().secondary()) {
 
                 uassert(ErrorCodes::NotMasterOrSecondary,
@@ -1596,43 +1597,43 @@ void mongo::execCommandDatabase(OperationContext* txn,
         if (maxTimeMS > 0) {
             uassert(40119,
                     "Illegal attempt to set operation deadline within DBDirectClient",
-                    !txn->getClient()->isInDirectClient());
-            txn->setDeadlineAfterNowBy(Milliseconds{maxTimeMS});
+                    !opCtx->getClient()->isInDirectClient());
+            opCtx->setDeadlineAfterNowBy(Milliseconds{maxTimeMS});
         }
 
         // Operations are only versioned against the primary. We also make sure not to redo shard
         // version handling if this command was issued via the direct client.
-        if (iAmPrimary && !txn->getClient()->isInDirectClient()) {
+        if (iAmPrimary && !opCtx->getClient()->isInDirectClient()) {
             // Handle a shard version that may have been sent along with the command.
             auto commandNS = NamespaceString(command->parseNs(dbname, request.getCommandArgs()));
-            auto& oss = OperationShardingState::get(txn);
+            auto& oss = OperationShardingState::get(opCtx);
             oss.initializeShardVersion(commandNS, extractedFields[kShardVersionFieldIdx]);
-            auto shardingState = ShardingState::get(txn);
+            auto shardingState = ShardingState::get(opCtx);
             if (oss.hasShardVersion()) {
                 uassertStatusOK(shardingState->canAcceptShardedCommands());
             }
 
             // Handle config optime information that may have been sent along with the command.
-            uassertStatusOK(shardingState->updateConfigServerOpTimeFromMetadata(txn));
+            uassertStatusOK(shardingState->updateConfigServerOpTimeFromMetadata(opCtx));
         }
 
         // Can throw
-        txn->checkForInterrupt();  // May trigger maxTimeAlwaysTimeOut fail point.
+        opCtx->checkForInterrupt();  // May trigger maxTimeAlwaysTimeOut fail point.
 
         bool retval = false;
 
-        CurOp::get(txn)->ensureStarted();
+        CurOp::get(opCtx)->ensureStarted();
 
         command->_commandsExecuted.increment();
 
         if (logger::globalLogDomain()->shouldLog(logger::LogComponent::kTracking,
                                                  logger::LogSeverity::Debug(1)) &&
-            rpc::TrackingMetadata::get(txn).getParentOperId()) {
+            rpc::TrackingMetadata::get(opCtx).getParentOperId()) {
             MONGO_LOG_COMPONENT(1, logger::LogComponent::kTracking)
-                << rpc::TrackingMetadata::get(txn).toString();
-            rpc::TrackingMetadata::get(txn).setIsLogged(true);
+                << rpc::TrackingMetadata::get(opCtx).toString();
+            rpc::TrackingMetadata::get(opCtx).setIsLogged(true);
         }
-        retval = command->run(txn, request, replyBuilder);
+        retval = command->run(opCtx, request, replyBuilder);
 
         dassert(replyBuilder->getState() == rpc::ReplyBuilderInterface::State::kOutputDocs);
 
@@ -1645,15 +1646,15 @@ void mongo::execCommandDatabase(OperationContext* txn,
             auto sce = dynamic_cast<const StaleConfigException*>(&e);
             invariant(sce);  // do not upcasts from DBException created by uassert variants.
 
-            ShardingState::get(txn)->onStaleShardVersion(
-                txn, NamespaceString(sce->getns()), sce->getVersionReceived());
+            ShardingState::get(opCtx)->onStaleShardVersion(
+                opCtx, NamespaceString(sce->getns()), sce->getVersionReceived());
         }
 
         BSONObjBuilder metadataBob;
-        appendOpTimeMetadata(txn, request, &metadataBob);
+        appendOpTimeMetadata(opCtx, request, &metadataBob);
 
-        auto operationTime = _getClientOperationTime(txn);
+        auto operationTime = _getClientOperationTime(opCtx);
         Command::generateErrorResponse(
-            txn, replyBuilder, e, request, command, metadataBob.done(), operationTime);
+            opCtx, replyBuilder, e, request, command, metadataBob.done(), operationTime);
     }
 }
diff --git a/src/mongo/db/commands/dbhash.cpp b/src/mongo/db/commands/dbhash.cpp
index 6d68cd93f00..0da2752a28d 100644
--- a/src/mongo/db/commands/dbhash.cpp
+++ b/src/mongo/db/commands/dbhash.cpp
@@ -80,7 +80,7 @@ public:
         out->push_back(Privilege(ResourcePattern::forDatabaseName(dbname), actions));
     }
 
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const string& dbname,
                      BSONObj& cmdObj,
                      int,
@@ -109,8 +109,8 @@ public:
 
         // We lock the entire database in S-mode in order to ensure that the contents will not
         // change for the snapshot.
-        ScopedTransaction scopedXact(txn, MODE_IS);
-        AutoGetDb autoDb(txn, ns, MODE_S);
+        ScopedTransaction scopedXact(opCtx, MODE_IS);
+        AutoGetDb autoDb(opCtx, ns, MODE_S);
         Database* db = autoDb.getDb();
         if (db) {
             db->getDatabaseCatalogEntry()->getCollectionNamespaces(&colls);
@@ -152,7 +152,7 @@ public:
                 continue;
 
             bool fromCache = false;
-            string hash = _hashCollection(txn, db, fullCollectionName, &fromCache);
+            string hash = _hashCollection(opCtx, db, fullCollectionName, &fromCache);
 
             bb.append(shortCollectionName, hash);
 
@@ -174,11 +174,11 @@ public:
         return 1;
     }
 
-    void wipeCacheForCollection(OperationContext* txn, const NamespaceString& ns) {
+    void wipeCacheForCollection(OperationContext* opCtx, const NamespaceString& ns) {
         if (!_isCachable(ns))
             return;
 
-        txn->recoveryUnit()->onCommit([this, txn, ns] {
+        opCtx->recoveryUnit()->onCommit([this, opCtx, ns] {
             stdx::lock_guard<stdx::mutex> lk(_cachedHashedMutex);
             if (ns.isCommand()) {
                 // The <dbName>.$cmd namespace can represent a command that
@@ -274,9 +274,9 @@ private:
 
 }  // namespace
 
-void logOpForDbHash(OperationContext* txn, const char* ns) {
+void logOpForDbHash(OperationContext* opCtx, const char* ns) {
     NamespaceString nsString(ns);
-    dbhashCmd.wipeCacheForCollection(txn, nsString);
+    dbhashCmd.wipeCacheForCollection(opCtx, nsString);
 }
 
 }  // namespace mongo
diff --git a/src/mongo/db/commands/dbhash.h b/src/mongo/db/commands/dbhash.h
index 2afc3efb454..09db7e97e0e 100644
--- a/src/mongo/db/commands/dbhash.h
+++ b/src/mongo/db/commands/dbhash.h
@@ -32,6 +32,6 @@ namespace mongo {
 
 class OperationContext;
 
-void logOpForDbHash(OperationContext* txn, const char* ns);
+void logOpForDbHash(OperationContext* opCtx, const char* ns);
 
 }  // namespace mongo
diff --git a/src/mongo/db/commands/distinct.cpp b/src/mongo/db/commands/distinct.cpp
index 0f619356f96..febed50512f 100644
--- a/src/mongo/db/commands/distinct.cpp
+++ b/src/mongo/db/commands/distinct.cpp
@@ -111,7 +111,7 @@ public:
         help << "{ distinct : 'collection name' , key : 'a.b' , query : {} }";
     }
 
-    virtual Status explain(OperationContext* txn,
+    virtual Status explain(OperationContext* opCtx,
                            const std::string& dbname,
                            const BSONObj& cmdObj,
                            ExplainCommon::Verbosity verbosity,
@@ -119,8 +119,8 @@ public:
                            BSONObjBuilder* out) const {
         const NamespaceString nss(parseNsCollectionRequired(dbname, cmdObj));
 
-        const ExtensionsCallbackReal extensionsCallback(txn, &nss);
-        auto parsedDistinct = ParsedDistinct::parse(txn, nss, cmdObj, extensionsCallback, true);
+        const ExtensionsCallbackReal extensionsCallback(opCtx, &nss);
+        auto parsedDistinct = ParsedDistinct::parse(opCtx, nss, cmdObj, extensionsCallback, true);
         if (!parsedDistinct.isOK()) {
             return parsedDistinct.getStatus();
         }
@@ -133,7 +133,7 @@ public:
                           "http://dochub.mongodb.org/core/3.4-feature-compatibility.");
         }
 
-        AutoGetCollectionOrViewForRead ctx(txn, nss);
+        AutoGetCollectionOrViewForRead ctx(opCtx, nss);
         Collection* collection = ctx.getCollection();
 
         if (ctx.getView()) {
@@ -145,12 +145,12 @@ public:
             }
             std::string errmsg;
             (void)Command::findCommand("aggregate")
-                ->run(txn, dbname, viewAggregation.getValue(), 0, errmsg, *out);
+                ->run(opCtx, dbname, viewAggregation.getValue(), 0, errmsg, *out);
             return Status::OK();
         }
 
         auto executor = getExecutorDistinct(
-            txn, collection, nss.ns(), &parsedDistinct.getValue(), PlanExecutor::YIELD_AUTO);
+            opCtx, collection, nss.ns(), &parsedDistinct.getValue(), PlanExecutor::YIELD_AUTO);
         if (!executor.isOK()) {
             return executor.getStatus();
         }
@@ -159,7 +159,7 @@ public:
         return Status::OK();
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int options,
@@ -167,8 +167,8 @@ public:
              BSONObjBuilder& result) {
         const NamespaceString nss(parseNsCollectionRequired(dbname, cmdObj));
 
-        const ExtensionsCallbackReal extensionsCallback(txn, &nss);
-        auto parsedDistinct = ParsedDistinct::parse(txn, nss, cmdObj, extensionsCallback, false);
+        const ExtensionsCallbackReal extensionsCallback(opCtx, &nss);
+        auto parsedDistinct = ParsedDistinct::parse(opCtx, nss, cmdObj, extensionsCallback, false);
         if (!parsedDistinct.isOK()) {
             return appendCommandStatus(result, parsedDistinct.getStatus());
         }
@@ -183,7 +183,7 @@ public:
                        "http://dochub.mongodb.org/core/3.4-feature-compatibility."));
         }
 
-        AutoGetCollectionOrViewForRead ctx(txn, nss);
+        AutoGetCollectionOrViewForRead ctx(opCtx, nss);
         Collection* collection = ctx.getCollection();
 
         if (ctx.getView()) {
@@ -196,7 +196,7 @@ public:
             BSONObjBuilder aggResult;
 
             (void)Command::findCommand("aggregate")
-                ->run(txn, dbname, viewAggregation.getValue(), options, errmsg, aggResult);
+                ->run(opCtx, dbname, viewAggregation.getValue(), options, errmsg, aggResult);
 
             if (ResolvedView::isResolvedViewErrorResponse(aggResult.asTempObj())) {
                 result.appendElements(aggResult.obj());
@@ -212,14 +212,14 @@ public:
         }
 
         auto executor = getExecutorDistinct(
-            txn, collection, nss.ns(), &parsedDistinct.getValue(), PlanExecutor::YIELD_AUTO);
+            opCtx, collection, nss.ns(), &parsedDistinct.getValue(), PlanExecutor::YIELD_AUTO);
         if (!executor.isOK()) {
             return appendCommandStatus(result, executor.getStatus());
         }
 
         {
-            stdx::lock_guard<Client> lk(*txn->getClient());
-            CurOp::get(txn)->setPlanSummary_inlock(
+            stdx::lock_guard<Client> lk(*opCtx->getClient());
+            CurOp::get(opCtx)->setPlanSummary_inlock(
                 Explain::getPlanSummary(executor.getValue().get()));
         }
 
@@ -274,13 +274,13 @@ public:
         }
 
 
-        auto curOp = CurOp::get(txn);
+        auto curOp = CurOp::get(opCtx);
 
         // Get summary information about the plan.
         PlanSummaryStats stats;
         Explain::getSummaryStats(*executor.getValue(), &stats);
         if (collection) {
-            collection->infoCache()->notifyOfQuery(txn, stats.indexesUsed);
+            collection->infoCache()->notifyOfQuery(opCtx, stats.indexesUsed);
         }
         curOp->debug().setPlanSummaryMetrics(stats);
 
diff --git a/src/mongo/db/commands/driverHelpers.cpp b/src/mongo/db/commands/driverHelpers.cpp
index 8b6163e678b..c25887bf0a2 100644
--- a/src/mongo/db/commands/driverHelpers.cpp
+++ b/src/mongo/db/commands/driverHelpers.cpp
@@ -73,7 +73,7 @@ public:
     virtual void addRequiredPrivileges(const std::string& dbname,
                                        const BSONObj& cmdObj,
                                        std::vector<Privilege>* out) {}  // No auth required
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const string&,
                      BSONObj& cmdObj,
                      int,
diff --git a/src/mongo/db/commands/drop_indexes.cpp b/src/mongo/db/commands/drop_indexes.cpp
index b3f2b73d21f..86082761cce 100644
--- a/src/mongo/db/commands/drop_indexes.cpp
+++ b/src/mongo/db/commands/drop_indexes.cpp
@@ -84,14 +84,14 @@ public:
     }
 
     CmdDropIndexes() : Command("dropIndexes", false, "deleteIndexes") {}
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& jsobj,
              int,
              string& errmsg,
              BSONObjBuilder& result) {
         const NamespaceString nss = parseNsCollectionRequired(dbname, jsobj);
-        return appendCommandStatus(result, dropIndexes(txn, nss, jsobj, &result));
+        return appendCommandStatus(result, dropIndexes(opCtx, nss, jsobj, &result));
     }
 
 } cmdDropIndexes;
@@ -116,25 +116,25 @@ public:
     }
     CmdReIndex() : Command("reIndex") {}
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& jsobj,
              int,
              string& errmsg,
              BSONObjBuilder& result) {
-        DBDirectClient db(txn);
+        DBDirectClient db(opCtx);
 
         const NamespaceString toReIndexNs = parseNsCollectionRequired(dbname, jsobj);
 
         LOG(0) << "CMD: reIndex " << toReIndexNs;
 
-        ScopedTransaction transaction(txn, MODE_IX);
-        Lock::DBLock dbXLock(txn->lockState(), dbname, MODE_X);
-        OldClientContext ctx(txn, toReIndexNs.ns());
+        ScopedTransaction transaction(opCtx, MODE_IX);
+        Lock::DBLock dbXLock(opCtx->lockState(), dbname, MODE_X);
+        OldClientContext ctx(opCtx, toReIndexNs.ns());
 
         Collection* collection = ctx.db()->getCollection(toReIndexNs.ns());
         if (!collection) {
-            if (ctx.db()->getViewCatalog()->lookup(txn, toReIndexNs.ns()))
+            if (ctx.db()->getViewCatalog()->lookup(opCtx, toReIndexNs.ns()))
                 return appendCommandStatus(
                     result, {ErrorCodes::CommandNotSupportedOnView, "can't re-index a view"});
             else
@@ -152,12 +152,12 @@ public:
         vector<BSONObj> all;
         {
             vector<string> indexNames;
-            collection->getCatalogEntry()->getAllIndexes(txn, &indexNames);
+            collection->getCatalogEntry()->getAllIndexes(opCtx, &indexNames);
             all.reserve(indexNames.size());
 
             for (size_t i = 0; i < indexNames.size(); i++) {
                 const string& name = indexNames[i];
-                BSONObj spec = collection->getCatalogEntry()->getIndexSpec(txn, name);
+                BSONObj spec = collection->getCatalogEntry()->getIndexSpec(opCtx, name);
 
                 {
                     BSONObjBuilder bob;
@@ -192,8 +192,8 @@ public:
         result.appendNumber("nIndexesWas", all.size());
 
         {
-            WriteUnitOfWork wunit(txn);
-            Status s = collection->getIndexCatalog()->dropAllIndexes(txn, true);
+            WriteUnitOfWork wunit(opCtx);
+            Status s = collection->getIndexCatalog()->dropAllIndexes(opCtx, true);
             if (!s.isOK()) {
                 errmsg = "dropIndexes failed";
                 return appendCommandStatus(result, s);
@@ -201,7 +201,7 @@ public:
             wunit.commit();
         }
 
-        MultiIndexBlock indexer(txn, collection);
+        MultiIndexBlock indexer(opCtx, collection);
         // do not want interruption as that will leave us without indexes.
 
         auto indexInfoObjs = indexer.init(all);
@@ -215,7 +215,7 @@ public:
         }
 
         {
-            WriteUnitOfWork wunit(txn);
+            WriteUnitOfWork wunit(opCtx);
             indexer.commit();
             wunit.commit();
         }
@@ -224,8 +224,8 @@ public:
         // This was also done when dropAllIndexes() committed, but we need to ensure that no one
         // tries to read in the intermediate state where all indexes are newer than the current
         // snapshot so are unable to be used.
-        auto replCoord = repl::ReplicationCoordinator::get(txn);
-        auto snapshotName = replCoord->reserveSnapshotName(txn);
+        auto replCoord = repl::ReplicationCoordinator::get(opCtx);
+        auto snapshotName = replCoord->reserveSnapshotName(opCtx);
         replCoord->forceSnapshotCreation();  // Ensures a newer snapshot gets created even if idle.
         collection->setMinimumVisibleSnapshot(snapshotName);
 
diff --git a/src/mongo/db/commands/eval.cpp b/src/mongo/db/commands/eval.cpp
index f9345d4247c..20945eb4828 100644
--- a/src/mongo/db/commands/eval.cpp
+++ b/src/mongo/db/commands/eval.cpp
@@ -58,7 +58,7 @@ namespace {
 
 const int edebug = 0;
 
-bool dbEval(OperationContext* txn,
+bool dbEval(OperationContext* opCtx,
             const string& dbName,
             const BSONObj& cmd,
             BSONObjBuilder& result,
@@ -92,7 +92,7 @@ bool dbEval(OperationContext* txn,
     }
 
     unique_ptr<Scope> s(getGlobalScriptEngine()->newScope());
-    s->registerOperation(txn);
+    s->registerOperation(opCtx);
 
     ScriptingFunction f = s->createFunction(code);
     if (f == 0) {
@@ -100,7 +100,7 @@ bool dbEval(OperationContext* txn,
         return false;
     }
 
-    s->localConnectForDbEval(txn, dbName.c_str());
+    s->localConnectForDbEval(opCtx, dbName.c_str());
 
     if (e.type() == CodeWScope) {
         s->init(e.codeWScopeScopeDataUnsafe());
@@ -171,22 +171,22 @@ public:
 
     CmdEval() : Command("eval", false, "$eval") {}
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int options,
              string& errmsg,
              BSONObjBuilder& result) {
         if (cmdObj["nolock"].trueValue()) {
-            return dbEval(txn, dbname, cmdObj, result, errmsg);
+            return dbEval(opCtx, dbname, cmdObj, result, errmsg);
         }
 
-        ScopedTransaction transaction(txn, MODE_X);
-        Lock::GlobalWrite lk(txn->lockState());
+        ScopedTransaction transaction(opCtx, MODE_X);
+        Lock::GlobalWrite lk(opCtx->lockState());
 
-        OldClientContext ctx(txn, dbname, false /* no shard version checking */);
+        OldClientContext ctx(opCtx, dbname, false /* no shard version checking */);
 
-        return dbEval(txn, dbname, cmdObj, result, errmsg);
+        return dbEval(opCtx, dbname, cmdObj, result, errmsg);
     }
 
 } cmdeval;
diff --git a/src/mongo/db/commands/explain_cmd.cpp b/src/mongo/db/commands/explain_cmd.cpp
index 678fd7effa2..7c72c26977f 100644
--- a/src/mongo/db/commands/explain_cmd.cpp
+++ b/src/mongo/db/commands/explain_cmd.cpp
@@ -89,7 +89,7 @@ public:
      * the command that you are explaining. The auth check is performed recursively
      * on the nested command.
      */
-    virtual Status checkAuthForOperation(OperationContext* txn,
+    virtual Status checkAuthForOperation(OperationContext* opCtx,
                                          const std::string& dbname,
                                          const BSONObj& cmdObj) {
         if (Object != cmdObj.firstElement().type()) {
@@ -105,10 +105,10 @@ public:
             return Status(ErrorCodes::CommandNotFound, ss);
         }
 
-        return commToExplain->checkAuthForOperation(txn, dbname, explainObj);
+        return commToExplain->checkAuthForOperation(opCtx, dbname, explainObj);
     }
 
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const std::string& dbname,
                      BSONObj& cmdObj,
                      int options,
@@ -135,12 +135,12 @@ public:
         // copied from Command::execCommand and should be abstracted. Until then, make
         // sure to keep it up to date.
         repl::ReplicationCoordinator* replCoord = repl::getGlobalReplicationCoordinator();
-        bool iAmPrimary = replCoord->canAcceptWritesForDatabase_UNSAFE(txn, dbname);
+        bool iAmPrimary = replCoord->canAcceptWritesForDatabase_UNSAFE(opCtx, dbname);
         bool commandCanRunOnSecondary = commToExplain->slaveOk();
 
         bool commandIsOverriddenToRunOnSecondary = commToExplain->slaveOverrideOk() &&
-            rpc::ServerSelectionMetadata::get(txn).canRunOnSecondary();
-        bool iAmStandalone = !txn->writesAreReplicated();
+            rpc::ServerSelectionMetadata::get(opCtx).canRunOnSecondary();
+        bool iAmStandalone = !opCtx->writesAreReplicated();
 
         const bool canRunHere = iAmPrimary || commandCanRunOnSecondary ||
             commandIsOverriddenToRunOnSecondary || iAmStandalone;
@@ -154,8 +154,12 @@ public:
         }
 
         // Actually call the nested command's explain(...) method.
-        Status explainStatus = commToExplain->explain(
-            txn, dbname, explainObj, verbosity, rpc::ServerSelectionMetadata::get(txn), &result);
+        Status explainStatus = commToExplain->explain(opCtx,
+                                                      dbname,
+                                                      explainObj,
+                                                      verbosity,
+                                                      rpc::ServerSelectionMetadata::get(opCtx),
+                                                      &result);
         if (!explainStatus.isOK()) {
             return appendCommandStatus(result, explainStatus);
         }
diff --git a/src/mongo/db/commands/fail_point_cmd.cpp b/src/mongo/db/commands/fail_point_cmd.cpp
index a298c267647..9e6795e9d78 100644
--- a/src/mongo/db/commands/fail_point_cmd.cpp
+++ b/src/mongo/db/commands/fail_point_cmd.cpp
@@ -90,7 +90,7 @@ public:
         h << "modifies the settings of a fail point";
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int,
diff --git a/src/mongo/db/commands/feature_compatibility_version.cpp b/src/mongo/db/commands/feature_compatibility_version.cpp
index 29d3a96513e..d97f5cf0c54 100644
--- a/src/mongo/db/commands/feature_compatibility_version.cpp
+++ b/src/mongo/db/commands/feature_compatibility_version.cpp
@@ -193,14 +193,14 @@ StatusWith<ServerGlobalParams::FeatureCompatibility::Version> FeatureCompatibili
     return version;
 }
 
-void FeatureCompatibilityVersion::set(OperationContext* txn, StringData version) {
+void FeatureCompatibilityVersion::set(OperationContext* opCtx, StringData version) {
     uassert(40284,
             "featureCompatibilityVersion must be '3.4' or '3.2'. See "
             "http://dochub.mongodb.org/core/3.4-feature-compatibility.",
             version == FeatureCompatibilityVersionCommandParser::kVersion34 ||
                 version == FeatureCompatibilityVersionCommandParser::kVersion32);
 
-    DBDirectClient client(txn);
+    DBDirectClient client(opCtx);
     NamespaceString nss(FeatureCompatibilityVersion::kCollection);
 
     if (version == FeatureCompatibilityVersionCommandParser::kVersion34) {
@@ -211,27 +211,28 @@ void FeatureCompatibilityVersion::set(OperationContext* txn, StringData version)
         std::vector<BSONObj> indexSpecs{k32IncompatibleIndexSpec};
 
         {
-            ScopedTransaction transaction(txn, MODE_IX);
-            AutoGetOrCreateDb autoDB(txn, nss.db(), MODE_X);
+            ScopedTransaction transaction(opCtx, MODE_IX);
+            AutoGetOrCreateDb autoDB(opCtx, nss.db(), MODE_X);
 
             uassert(ErrorCodes::NotMaster,
                     str::stream() << "Cannot set featureCompatibilityVersion to '" << version
                                   << "'. Not primary while attempting to create index on: "
                                   << nss.ns(),
-                    repl::ReplicationCoordinator::get(txn->getServiceContext())
-                        ->canAcceptWritesFor(txn, nss));
+                    repl::ReplicationCoordinator::get(opCtx->getServiceContext())
+                        ->canAcceptWritesFor(opCtx, nss));
 
             IndexBuilder builder(k32IncompatibleIndexSpec, false);
-            auto status = builder.buildInForeground(txn, autoDB.getDb());
+            auto status = builder.buildInForeground(opCtx, autoDB.getDb());
             uassertStatusOK(status);
 
             MONGO_WRITE_CONFLICT_RETRY_LOOP_BEGIN {
-                WriteUnitOfWork wuow(txn);
+                WriteUnitOfWork wuow(opCtx);
                 getGlobalServiceContext()->getOpObserver()->onCreateIndex(
-                    txn, autoDB.getDb()->getSystemIndexesName(), k32IncompatibleIndexSpec, false);
+                    opCtx, autoDB.getDb()->getSystemIndexesName(), k32IncompatibleIndexSpec, false);
                 wuow.commit();
             }
-            MONGO_WRITE_CONFLICT_RETRY_LOOP_END(txn, "FeatureCompatibilityVersion::set", nss.ns());
+            MONGO_WRITE_CONFLICT_RETRY_LOOP_END(
+                opCtx, "FeatureCompatibilityVersion::set", nss.ns());
         }
 
         // We then update the featureCompatibilityVersion document stored in the
@@ -279,7 +280,7 @@ void FeatureCompatibilityVersion::set(OperationContext* txn, StringData version)
     }
 }
 
-void FeatureCompatibilityVersion::setIfCleanStartup(OperationContext* txn,
+void FeatureCompatibilityVersion::setIfCleanStartup(OperationContext* opCtx,
                                                     repl::StorageInterface* storageInterface) {
     if (serverGlobalParams.clusterRole != ClusterRole::ShardServer) {
         std::vector<std::string> dbNames;
@@ -292,7 +293,7 @@ void FeatureCompatibilityVersion::setIfCleanStartup(OperationContext* txn,
             }
         }
 
-        UnreplicatedWritesBlock unreplicatedWritesBlock(txn);
+        UnreplicatedWritesBlock unreplicatedWritesBlock(opCtx);
         NamespaceString nss(FeatureCompatibilityVersion::kCollection);
 
         // We build a v=2 index on the "admin.system.version" collection as part of setting the
@@ -302,11 +303,11 @@ void FeatureCompatibilityVersion::setIfCleanStartup(OperationContext* txn,
         std::vector<BSONObj> indexSpecs{k32IncompatibleIndexSpec};
 
         {
-            ScopedTransaction transaction(txn, MODE_IX);
-            AutoGetOrCreateDb autoDB(txn, nss.db(), MODE_X);
+            ScopedTransaction transaction(opCtx, MODE_IX);
+            AutoGetOrCreateDb autoDB(opCtx, nss.db(), MODE_X);
 
             IndexBuilder builder(k32IncompatibleIndexSpec, false);
-            auto status = builder.buildInForeground(txn, autoDB.getDb());
+            auto status = builder.buildInForeground(opCtx, autoDB.getDb());
             uassertStatusOK(status);
         }
 
@@ -317,7 +318,7 @@ void FeatureCompatibilityVersion::setIfCleanStartup(OperationContext* txn,
         // document when starting up, then on a subsequent start-up we'd no longer consider the data
         // files "clean" and would instead be in featureCompatibilityVersion=3.2.
         uassertStatusOK(storageInterface->insertDocument(
-            txn,
+            opCtx,
             nss,
             BSON("_id" << FeatureCompatibilityVersion::kParameterName
                        << FeatureCompatibilityVersion::kVersionField
@@ -372,7 +373,7 @@ public:
                           false   // allowedToChangeAtRuntime
                           ) {}
 
-    virtual void append(OperationContext* txn, BSONObjBuilder& b, const std::string& name) {
+    virtual void append(OperationContext* opCtx, BSONObjBuilder& b, const std::string& name) {
         b.append(name,
                  getFeatureCompatibilityVersionString(
                      serverGlobalParams.featureCompatibility.version.load()));
diff --git a/src/mongo/db/commands/feature_compatibility_version.h b/src/mongo/db/commands/feature_compatibility_version.h
index 4bcb4b56e55..44029c72e21 100644
--- a/src/mongo/db/commands/feature_compatibility_version.h
+++ b/src/mongo/db/commands/feature_compatibility_version.h
@@ -66,13 +66,14 @@ public:
      * available.
      * 'version' should be '3.4' or '3.2'.
      */
-    static void set(OperationContext* txn, StringData version);
+    static void set(OperationContext* opCtx, StringData version);
 
     /**
      * If there are no non-local databases and we are not running with --shardsvr, set
      * featureCompatibilityVersion to 3.4.
      */
-    static void setIfCleanStartup(OperationContext* txn, repl::StorageInterface* storageInterface);
+    static void setIfCleanStartup(OperationContext* opCtx,
+                                  repl::StorageInterface* storageInterface);
 
     /**
      * Examines a document inserted or updated in admin.system.version. If it is the
diff --git a/src/mongo/db/commands/find_and_modify.cpp b/src/mongo/db/commands/find_and_modify.cpp
index d0a260164d4..3aa7eb2018c 100644
--- a/src/mongo/db/commands/find_and_modify.cpp
+++ b/src/mongo/db/commands/find_and_modify.cpp
@@ -105,7 +105,7 @@ const DeleteStats* getDeleteStats(const PlanExecutor* exec) {
  *
  * If the operation failed, then an error Status is returned.
  */
-StatusWith<boost::optional<BSONObj>> advanceExecutor(OperationContext* txn,
+StatusWith<boost::optional<BSONObj>> advanceExecutor(OperationContext* opCtx,
                                                      PlanExecutor* exec,
                                                      bool isRemove) {
     BSONObj value;
@@ -191,8 +191,8 @@ void appendCommandResponse(PlanExecutor* exec,
     }
 }
 
-Status checkCanAcceptWritesForDatabase(OperationContext* txn, const NamespaceString& nsString) {
-    if (!repl::getGlobalReplicationCoordinator()->canAcceptWritesFor(txn, nsString)) {
+Status checkCanAcceptWritesForDatabase(OperationContext* opCtx, const NamespaceString& nsString) {
+    if (!repl::getGlobalReplicationCoordinator()->canAcceptWritesFor(opCtx, nsString)) {
         return Status(ErrorCodes::NotMaster,
                       str::stream()
                           << "Not primary while running findAndModify command on collection "
@@ -201,12 +201,12 @@ Status checkCanAcceptWritesForDatabase(OperationContext* txn, const NamespaceStr
     return Status::OK();
 }
 
-void recordStatsForTopCommand(OperationContext* txn) {
-    auto curOp = CurOp::get(txn);
+void recordStatsForTopCommand(OperationContext* opCtx) {
+    auto curOp = CurOp::get(opCtx);
     const int writeLocked = 1;
 
-    Top::get(txn->getClient()->getServiceContext())
-        .record(txn,
+    Top::get(opCtx->getClient()->getServiceContext())
+        .record(opCtx,
                 curOp->getNS(),
                 curOp->getLogicalOp(),
                 writeLocked,
@@ -249,7 +249,7 @@ public:
         return ReadWriteType::kWrite;
     }
 
-    Status explain(OperationContext* txn,
+    Status explain(OperationContext* opCtx,
                    const std::string& dbName,
                    const BSONObj& cmdObj,
                    ExplainCommon::Verbosity verbosity,
@@ -269,14 +269,14 @@ public:
 
         const FindAndModifyRequest& args = parseStatus.getValue();
         const NamespaceString& nsString = args.getNamespaceString();
-        OpDebug* opDebug = &CurOp::get(txn)->debug();
+        OpDebug* opDebug = &CurOp::get(opCtx)->debug();
 
         if (args.isRemove()) {
             DeleteRequest request(nsString);
             const bool isExplain = true;
             makeDeleteRequest(args, isExplain, &request);
 
-            ParsedDelete parsedDelete(txn, &request);
+            ParsedDelete parsedDelete(opCtx, &request);
             Status parsedDeleteStatus = parsedDelete.parseRequest();
             if (!parsedDeleteStatus.isOK()) {
                 return parsedDeleteStatus;
@@ -284,18 +284,18 @@ public:
 
             // Explain calls of the findAndModify command are read-only, but we take write
             // locks so that the timing information is more accurate.
-            AutoGetCollection autoColl(txn, nsString, MODE_IX);
+            AutoGetCollection autoColl(opCtx, nsString, MODE_IX);
             if (!autoColl.getDb()) {
                 return {ErrorCodes::NamespaceNotFound,
                         str::stream() << "database " << dbName << " does not exist."};
             }
 
-            auto css = CollectionShardingState::get(txn, nsString);
-            css->checkShardVersionOrThrow(txn);
+            auto css = CollectionShardingState::get(opCtx, nsString);
+            css->checkShardVersionOrThrow(opCtx);
 
             Collection* const collection = autoColl.getCollection();
             auto statusWithPlanExecutor =
-                getExecutorDelete(txn, opDebug, collection, &parsedDelete);
+                getExecutorDelete(opCtx, opDebug, collection, &parsedDelete);
             if (!statusWithPlanExecutor.isOK()) {
                 return statusWithPlanExecutor.getStatus();
             }
@@ -307,7 +307,7 @@ public:
             const bool isExplain = true;
             makeUpdateRequest(args, isExplain, &updateLifecycle, &request);
 
-            ParsedUpdate parsedUpdate(txn, &request);
+            ParsedUpdate parsedUpdate(opCtx, &request);
             Status parsedUpdateStatus = parsedUpdate.parseRequest();
             if (!parsedUpdateStatus.isOK()) {
                 return parsedUpdateStatus;
@@ -315,18 +315,18 @@ public:
 
             // Explain calls of the findAndModify command are read-only, but we take write
             // locks so that the timing information is more accurate.
-            AutoGetCollection autoColl(txn, nsString, MODE_IX);
+            AutoGetCollection autoColl(opCtx, nsString, MODE_IX);
             if (!autoColl.getDb()) {
                 return {ErrorCodes::NamespaceNotFound,
                         str::stream() << "database " << dbName << " does not exist."};
             }
 
-            auto css = CollectionShardingState::get(txn, nsString);
-            css->checkShardVersionOrThrow(txn);
+            auto css = CollectionShardingState::get(opCtx, nsString);
+            css->checkShardVersionOrThrow(opCtx);
 
             Collection* collection = autoColl.getCollection();
             auto statusWithPlanExecutor =
-                getExecutorUpdate(txn, opDebug, collection, &parsedUpdate);
+                getExecutorUpdate(opCtx, opDebug, collection, &parsedUpdate);
             if (!statusWithPlanExecutor.isOK()) {
                 return statusWithPlanExecutor.getStatus();
             }
@@ -337,14 +337,14 @@ public:
         return Status::OK();
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const std::string& dbName,
              BSONObj& cmdObj,
              int options,
              std::string& errmsg,
              BSONObjBuilder& result) override {
         // findAndModify command is not replicated directly.
-        invariant(txn->writesAreReplicated());
+        invariant(opCtx->writesAreReplicated());
         const NamespaceString fullNs = parseNsCollectionRequired(dbName, cmdObj);
         Status allowedWriteStatus = userAllowedWriteNS(fullNs.ns());
         if (!allowedWriteStatus.isOK()) {
@@ -362,21 +362,21 @@ public:
 
         boost::optional<DisableDocumentValidation> maybeDisableValidation;
         if (shouldBypassDocumentValidationForCommand(cmdObj))
-            maybeDisableValidation.emplace(txn);
+            maybeDisableValidation.emplace(opCtx);
 
-        auto client = txn->getClient();
+        auto client = opCtx->getClient();
         auto lastOpAtOperationStart = repl::ReplClientInfo::forClient(client).getLastOp();
         ScopeGuard lastOpSetterGuard =
             MakeObjGuard(repl::ReplClientInfo::forClient(client),
                          &repl::ReplClientInfo::setLastOpToSystemLastOpTime,
-                         txn);
+                         opCtx);
 
         // If this is the local database, don't set last op.
         if (dbName == "local") {
             lastOpSetterGuard.Dismiss();
         }
 
-        auto curOp = CurOp::get(txn);
+        auto curOp = CurOp::get(opCtx);
         OpDebug* opDebug = &curOp->debug();
 
         // Although usually the PlanExecutor handles WCE internally, it will throw WCEs when it is
@@ -388,38 +388,38 @@ public:
                 const bool isExplain = false;
                 makeDeleteRequest(args, isExplain, &request);
 
-                ParsedDelete parsedDelete(txn, &request);
+                ParsedDelete parsedDelete(opCtx, &request);
                 Status parsedDeleteStatus = parsedDelete.parseRequest();
                 if (!parsedDeleteStatus.isOK()) {
                     return appendCommandStatus(result, parsedDeleteStatus);
                 }
 
-                AutoGetOrCreateDb autoDb(txn, dbName, MODE_IX);
-                Lock::CollectionLock collLock(txn->lockState(), nsString.ns(), MODE_IX);
+                AutoGetOrCreateDb autoDb(opCtx, dbName, MODE_IX);
+                Lock::CollectionLock collLock(opCtx->lockState(), nsString.ns(), MODE_IX);
 
                 // Attach the namespace and database profiling level to the current op.
                 {
-                    stdx::lock_guard<Client> lk(*txn->getClient());
-                    CurOp::get(txn)->enter_inlock(nsString.ns().c_str(),
-                                                  autoDb.getDb()->getProfilingLevel());
+                    stdx::lock_guard<Client> lk(*opCtx->getClient());
+                    CurOp::get(opCtx)->enter_inlock(nsString.ns().c_str(),
+                                                    autoDb.getDb()->getProfilingLevel());
                 }
 
-                auto css = CollectionShardingState::get(txn, nsString);
-                css->checkShardVersionOrThrow(txn);
+                auto css = CollectionShardingState::get(opCtx, nsString);
+                css->checkShardVersionOrThrow(opCtx);
 
-                Status isPrimary = checkCanAcceptWritesForDatabase(txn, nsString);
+                Status isPrimary = checkCanAcceptWritesForDatabase(opCtx, nsString);
                 if (!isPrimary.isOK()) {
                     return appendCommandStatus(result, isPrimary);
                 }
 
                 Collection* const collection = autoDb.getDb()->getCollection(nsString.ns());
-                if (!collection && autoDb.getDb()->getViewCatalog()->lookup(txn, nsString.ns())) {
+                if (!collection && autoDb.getDb()->getViewCatalog()->lookup(opCtx, nsString.ns())) {
                     return appendCommandStatus(result,
                                                {ErrorCodes::CommandNotSupportedOnView,
                                                 "findAndModify not supported on a view"});
                 }
                 auto statusWithPlanExecutor =
-                    getExecutorDelete(txn, opDebug, collection, &parsedDelete);
+                    getExecutorDelete(opCtx, opDebug, collection, &parsedDelete);
                 if (!statusWithPlanExecutor.isOK()) {
                     return appendCommandStatus(result, statusWithPlanExecutor.getStatus());
                 }
@@ -427,12 +427,12 @@ public:
                     std::move(statusWithPlanExecutor.getValue());
 
                 {
-                    stdx::lock_guard<Client> lk(*txn->getClient());
-                    CurOp::get(txn)->setPlanSummary_inlock(Explain::getPlanSummary(exec.get()));
+                    stdx::lock_guard<Client> lk(*opCtx->getClient());
+                    CurOp::get(opCtx)->setPlanSummary_inlock(Explain::getPlanSummary(exec.get()));
                 }
 
                 StatusWith<boost::optional<BSONObj>> advanceStatus =
-                    advanceExecutor(txn, exec.get(), args.isRemove());
+                    advanceExecutor(opCtx, exec.get(), args.isRemove());
                 if (!advanceStatus.isOK()) {
                     return appendCommandStatus(result, advanceStatus.getStatus());
                 }
@@ -443,7 +443,7 @@ public:
                 PlanSummaryStats summaryStats;
                 Explain::getSummaryStats(*exec, &summaryStats);
                 if (collection) {
-                    collection->infoCache()->notifyOfQuery(txn, summaryStats.indexesUsed);
+                    collection->infoCache()->notifyOfQuery(opCtx, summaryStats.indexesUsed);
                 }
                 opDebug->setPlanSummaryMetrics(summaryStats);
 
@@ -455,7 +455,7 @@ public:
                     Explain::getWinningPlanStats(exec.get(), &execStatsBob);
                     curOp->debug().execStats = execStatsBob.obj();
                 }
-                recordStatsForTopCommand(txn);
+                recordStatsForTopCommand(opCtx);
 
                 boost::optional<BSONObj> value = advanceStatus.getValue();
                 appendCommandResponse(exec.get(), args.isRemove(), value, result);
@@ -465,32 +465,32 @@ public:
                 const bool isExplain = false;
                 makeUpdateRequest(args, isExplain, &updateLifecycle, &request);
 
-                ParsedUpdate parsedUpdate(txn, &request);
+                ParsedUpdate parsedUpdate(opCtx, &request);
                 Status parsedUpdateStatus = parsedUpdate.parseRequest();
                 if (!parsedUpdateStatus.isOK()) {
                     return appendCommandStatus(result, parsedUpdateStatus);
                 }
 
-                AutoGetOrCreateDb autoDb(txn, dbName, MODE_IX);
-                Lock::CollectionLock collLock(txn->lockState(), nsString.ns(), MODE_IX);
+                AutoGetOrCreateDb autoDb(opCtx, dbName, MODE_IX);
+                Lock::CollectionLock collLock(opCtx->lockState(), nsString.ns(), MODE_IX);
 
                 // Attach the namespace and database profiling level to the current op.
                 {
-                    stdx::lock_guard<Client> lk(*txn->getClient());
-                    CurOp::get(txn)->enter_inlock(nsString.ns().c_str(),
-                                                  autoDb.getDb()->getProfilingLevel());
+                    stdx::lock_guard<Client> lk(*opCtx->getClient());
+                    CurOp::get(opCtx)->enter_inlock(nsString.ns().c_str(),
+                                                    autoDb.getDb()->getProfilingLevel());
                 }
 
-                auto css = CollectionShardingState::get(txn, nsString);
-                css->checkShardVersionOrThrow(txn);
+                auto css = CollectionShardingState::get(opCtx, nsString);
+                css->checkShardVersionOrThrow(opCtx);
 
-                Status isPrimary = checkCanAcceptWritesForDatabase(txn, nsString);
+                Status isPrimary = checkCanAcceptWritesForDatabase(opCtx, nsString);
                 if (!isPrimary.isOK()) {
                     return appendCommandStatus(result, isPrimary);
                 }
 
                 Collection* collection = autoDb.getDb()->getCollection(nsString.ns());
-                if (!collection && autoDb.getDb()->getViewCatalog()->lookup(txn, nsString.ns())) {
+                if (!collection && autoDb.getDb()->getViewCatalog()->lookup(opCtx, nsString.ns())) {
                     return appendCommandStatus(result,
                                                {ErrorCodes::CommandNotSupportedOnView,
                                                 "findAndModify not supported on a view"});
@@ -503,7 +503,7 @@ public:
                     // in exclusive mode in order to create the collection.
                     collLock.relockAsDatabaseExclusive(autoDb.lock());
                     collection = autoDb.getDb()->getCollection(nsString.ns());
-                    Status isPrimaryAfterRelock = checkCanAcceptWritesForDatabase(txn, nsString);
+                    Status isPrimaryAfterRelock = checkCanAcceptWritesForDatabase(opCtx, nsString);
                     if (!isPrimaryAfterRelock.isOK()) {
                         return appendCommandStatus(result, isPrimaryAfterRelock);
                     }
@@ -511,9 +511,9 @@ public:
                     if (collection) {
                         // Someone else beat us to creating the collection, do nothing.
                     } else {
-                        WriteUnitOfWork wuow(txn);
+                        WriteUnitOfWork wuow(opCtx);
                         Status createCollStatus =
-                            userCreateNS(txn, autoDb.getDb(), nsString.ns(), BSONObj());
+                            userCreateNS(opCtx, autoDb.getDb(), nsString.ns(), BSONObj());
                         if (!createCollStatus.isOK()) {
                             return appendCommandStatus(result, createCollStatus);
                         }
@@ -525,7 +525,7 @@ public:
                 }
 
                 auto statusWithPlanExecutor =
-                    getExecutorUpdate(txn, opDebug, collection, &parsedUpdate);
+                    getExecutorUpdate(opCtx, opDebug, collection, &parsedUpdate);
                 if (!statusWithPlanExecutor.isOK()) {
                     return appendCommandStatus(result, statusWithPlanExecutor.getStatus());
                 }
@@ -533,12 +533,12 @@ public:
                     std::move(statusWithPlanExecutor.getValue());
 
                 {
-                    stdx::lock_guard<Client> lk(*txn->getClient());
-                    CurOp::get(txn)->setPlanSummary_inlock(Explain::getPlanSummary(exec.get()));
+                    stdx::lock_guard<Client> lk(*opCtx->getClient());
+                    CurOp::get(opCtx)->setPlanSummary_inlock(Explain::getPlanSummary(exec.get()));
                 }
 
                 StatusWith<boost::optional<BSONObj>> advanceStatus =
-                    advanceExecutor(txn, exec.get(), args.isRemove());
+                    advanceExecutor(opCtx, exec.get(), args.isRemove());
                 if (!advanceStatus.isOK()) {
                     return appendCommandStatus(result, advanceStatus.getStatus());
                 }
@@ -549,7 +549,7 @@ public:
                 PlanSummaryStats summaryStats;
                 Explain::getSummaryStats(*exec, &summaryStats);
                 if (collection) {
-                    collection->infoCache()->notifyOfQuery(txn, summaryStats.indexesUsed);
+                    collection->infoCache()->notifyOfQuery(opCtx, summaryStats.indexesUsed);
                 }
                 UpdateStage::recordUpdateStatsInOpDebug(getUpdateStats(exec.get()), opDebug);
                 opDebug->setPlanSummaryMetrics(summaryStats);
@@ -559,13 +559,13 @@ public:
                     Explain::getWinningPlanStats(exec.get(), &execStatsBob);
                     curOp->debug().execStats = execStatsBob.obj();
                 }
-                recordStatsForTopCommand(txn);
+                recordStatsForTopCommand(opCtx);
 
                 boost::optional<BSONObj> value = advanceStatus.getValue();
                 appendCommandResponse(exec.get(), args.isRemove(), value, result);
             }
         }
-        MONGO_WRITE_CONFLICT_RETRY_LOOP_END(txn, "findAndModify", nsString.ns());
+        MONGO_WRITE_CONFLICT_RETRY_LOOP_END(opCtx, "findAndModify", nsString.ns());
 
         if (repl::ReplClientInfo::forClient(client).getLastOp() != lastOpAtOperationStart) {
             // If this operation has already generated a new lastOp, don't bother setting it here.
diff --git a/src/mongo/db/commands/find_cmd.cpp b/src/mongo/db/commands/find_cmd.cpp
index d2b5075e283..c3d8e88b227 100644
--- a/src/mongo/db/commands/find_cmd.cpp
+++ b/src/mongo/db/commands/find_cmd.cpp
@@ -129,7 +129,7 @@ public:
         return AuthorizationSession::get(client)->checkAuthForFind(nss, hasTerm);
     }
 
-    Status explain(OperationContext* txn,
+    Status explain(OperationContext* opCtx,
                    const std::string& dbname,
                    const BSONObj& cmdObj,
                    ExplainCommon::Verbosity verbosity,
@@ -158,9 +158,9 @@ public:
 
         // Finish the parsing step by using the QueryRequest to create a CanonicalQuery.
 
-        ExtensionsCallbackReal extensionsCallback(txn, &nss);
+        ExtensionsCallbackReal extensionsCallback(opCtx, &nss);
         auto statusWithCQ =
-            CanonicalQuery::canonicalize(txn, std::move(qrStatus.getValue()), extensionsCallback);
+            CanonicalQuery::canonicalize(opCtx, std::move(qrStatus.getValue()), extensionsCallback);
         if (!statusWithCQ.isOK()) {
             return statusWithCQ.getStatus();
         }
@@ -168,7 +168,7 @@ public:
 
         // Acquire locks. If the namespace is a view, we release our locks and convert the query
         // request into an aggregation command.
-        AutoGetCollectionOrViewForRead ctx(txn, nss);
+        AutoGetCollectionOrViewForRead ctx(opCtx, nss);
         if (ctx.getView()) {
             // Relinquish locks. The aggregation command will re-acquire them.
             ctx.releaseLocksForView();
@@ -184,7 +184,7 @@ public:
             std::string errmsg;
 
             try {
-                agg->run(txn, dbname, viewAggregationCommand.getValue(), 0, errmsg, *out);
+                agg->run(opCtx, dbname, viewAggregationCommand.getValue(), 0, errmsg, *out);
             } catch (DBException& error) {
                 if (error.getCode() == ErrorCodes::InvalidPipelineOperator) {
                     return {ErrorCodes::InvalidPipelineOperator,
@@ -201,7 +201,7 @@ public:
 
         // We have a parsed query. Time to get the execution plan for it.
         auto statusWithPlanExecutor =
-            getExecutorFind(txn, collection, nss, std::move(cq), PlanExecutor::YIELD_AUTO);
+            getExecutorFind(opCtx, collection, nss, std::move(cq), PlanExecutor::YIELD_AUTO);
         if (!statusWithPlanExecutor.isOK()) {
             return statusWithPlanExecutor.getStatus();
         }
@@ -221,7 +221,7 @@ public:
      *   --Save state for getMore, transferring ownership of the executor to a ClientCursor.
      *   --Generate response to send to the client.
      */
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const std::string& dbname,
              BSONObj& cmdObj,
              int options,
@@ -237,7 +237,7 @@ public:
         // Although it is a command, a find command gets counted as a query.
         globalOpCounters.gotQuery();
 
-        if (txn->getClient()->isInDirectClient()) {
+        if (opCtx->getClient()->isInDirectClient()) {
             return appendCommandStatus(
                 result,
                 Status(ErrorCodes::IllegalOperation, "Cannot run find command from eval()"));
@@ -264,8 +264,8 @@ public:
 
         // Validate term before acquiring locks, if provided.
         if (auto term = qr->getReplicationTerm()) {
-            auto replCoord = repl::ReplicationCoordinator::get(txn);
-            Status status = replCoord->updateTerm(txn, *term);
+            auto replCoord = repl::ReplicationCoordinator::get(opCtx);
+            Status status = replCoord->updateTerm(opCtx, *term);
             // Note: updateTerm returns ok if term stayed the same.
             if (!status.isOK()) {
                 return appendCommandStatus(result, status);
@@ -279,11 +279,11 @@ public:
         // find command parameters, so these fields are redundant.
         const int ntoreturn = -1;
         const int ntoskip = -1;
-        beginQueryOp(txn, nss, cmdObj, ntoreturn, ntoskip);
+        beginQueryOp(opCtx, nss, cmdObj, ntoreturn, ntoskip);
 
         // Finish the parsing step by using the QueryRequest to create a CanonicalQuery.
-        ExtensionsCallbackReal extensionsCallback(txn, &nss);
-        auto statusWithCQ = CanonicalQuery::canonicalize(txn, std::move(qr), extensionsCallback);
+        ExtensionsCallbackReal extensionsCallback(opCtx, &nss);
+        auto statusWithCQ = CanonicalQuery::canonicalize(opCtx, std::move(qr), extensionsCallback);
         if (!statusWithCQ.isOK()) {
             return appendCommandStatus(result, statusWithCQ.getStatus());
         }
@@ -291,7 +291,7 @@ public:
 
         // Acquire locks. If the query is on a view, we release our locks and convert the query
         // request into an aggregation command.
-        AutoGetCollectionOrViewForRead ctx(txn, nss);
+        AutoGetCollectionOrViewForRead ctx(opCtx, nss);
         Collection* collection = ctx.getCollection();
         if (ctx.getView()) {
             // Relinquish locks. The aggregation command will re-acquire them.
@@ -306,7 +306,7 @@ public:
 
             Command* agg = Command::findCommand("aggregate");
             try {
-                agg->run(txn, dbname, viewAggregationCommand.getValue(), options, errmsg, result);
+                agg->run(opCtx, dbname, viewAggregationCommand.getValue(), options, errmsg, result);
             } catch (DBException& error) {
                 if (error.getCode() == ErrorCodes::InvalidPipelineOperator) {
                     return appendCommandStatus(
@@ -321,7 +321,7 @@ public:
 
         // Get the execution plan for the query.
         auto statusWithPlanExecutor =
-            getExecutorFind(txn, collection, nss, std::move(cq), PlanExecutor::YIELD_AUTO);
+            getExecutorFind(opCtx, collection, nss, std::move(cq), PlanExecutor::YIELD_AUTO);
         if (!statusWithPlanExecutor.isOK()) {
             return appendCommandStatus(result, statusWithPlanExecutor.getStatus());
         }
@@ -329,8 +329,8 @@ public:
         std::unique_ptr<PlanExecutor> exec = std::move(statusWithPlanExecutor.getValue());
 
         {
-            stdx::lock_guard<Client> lk(*txn->getClient());
-            CurOp::get(txn)->setPlanSummary_inlock(Explain::getPlanSummary(exec.get()));
+            stdx::lock_guard<Client> lk(*opCtx->getClient());
+            CurOp::get(opCtx)->setPlanSummary_inlock(Explain::getPlanSummary(exec.get()));
         }
 
         if (!collection) {
@@ -338,7 +338,7 @@ public:
             // there is no ClientCursor id, and then return.
             const long long numResults = 0;
             const CursorId cursorId = 0;
-            endQueryOp(txn, collection, *exec, numResults, cursorId);
+            endQueryOp(opCtx, collection, *exec, numResults, cursorId);
             appendCursorResponseObject(cursorId, nss.ns(), BSONArray(), &result);
             return true;
         }
@@ -378,12 +378,12 @@ public:
 
         // Before saving the cursor, ensure that whatever plan we established happened with the
         // expected collection version
-        auto css = CollectionShardingState::get(txn, nss);
-        css->checkShardVersionOrThrow(txn);
+        auto css = CollectionShardingState::get(opCtx, nss);
+        css->checkShardVersionOrThrow(opCtx);
 
         // Set up the cursor for getMore.
         CursorId cursorId = 0;
-        if (shouldSaveCursor(txn, collection, state, exec.get())) {
+        if (shouldSaveCursor(opCtx, collection, state, exec.get())) {
             // Register the execution plan inside a ClientCursor. Ownership of the PlanExecutor is
             // transferred to the ClientCursor.
             //
@@ -395,7 +395,7 @@ public:
             ClientCursorPin pinnedCursor = collection->getCursorManager()->registerCursor(
                 {exec.release(),
                  nss.ns(),
-                 txn->recoveryUnit()->isReadingFromMajorityCommittedSnapshot(),
+                 opCtx->recoveryUnit()->isReadingFromMajorityCommittedSnapshot(),
                  originalQR.getOptions(),
                  cmdObj.getOwned()});
             cursorId = pinnedCursor.getCursor()->cursorid();
@@ -407,13 +407,13 @@ public:
             cursorExec->saveState();
             cursorExec->detachFromOperationContext();
 
-            pinnedCursor.getCursor()->setLeftoverMaxTimeMicros(txn->getRemainingMaxTimeMicros());
+            pinnedCursor.getCursor()->setLeftoverMaxTimeMicros(opCtx->getRemainingMaxTimeMicros());
             pinnedCursor.getCursor()->setPos(numResults);
 
             // Fill out curop based on the results.
-            endQueryOp(txn, collection, *cursorExec, numResults, cursorId);
+            endQueryOp(opCtx, collection, *cursorExec, numResults, cursorId);
         } else {
-            endQueryOp(txn, collection, *exec, numResults, cursorId);
+            endQueryOp(opCtx, collection, *exec, numResults, cursorId);
         }
 
         // Generate the response object to send to the client.
diff --git a/src/mongo/db/commands/fsync.cpp b/src/mongo/db/commands/fsync.cpp
index 01d922cec02..dfe417b6c06 100644
--- a/src/mongo/db/commands/fsync.cpp
+++ b/src/mongo/db/commands/fsync.cpp
@@ -117,13 +117,13 @@ public:
         actions.addAction(ActionType::fsync);
         out->push_back(Privilege(ResourcePattern::forClusterResource(), actions));
     }
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const string& dbname,
                      BSONObj& cmdObj,
                      int,
                      string& errmsg,
                      BSONObjBuilder& result) {
-        if (txn->lockState()->isLocked()) {
+        if (opCtx->lockState()->isLocked()) {
             errmsg = "fsync: Cannot execute fsync command from contexts that hold a data lock";
             return false;
         }
@@ -138,23 +138,23 @@ public:
             // the simple fsync command case
             if (sync) {
                 // can this be GlobalRead? and if it can, it should be nongreedy.
-                ScopedTransaction transaction(txn, MODE_X);
-                Lock::GlobalWrite w(txn->lockState());
+                ScopedTransaction transaction(opCtx, MODE_X);
+                Lock::GlobalWrite w(opCtx->lockState());
                 // TODO SERVER-26822: Replace MMAPv1 specific calls with ones that are storage
                 // engine agnostic.
-                getDur().commitNow(txn);
+                getDur().commitNow(opCtx);
 
                 //  No WriteUnitOfWork needed, as this does no writes of its own.
             }
 
             // Take a global IS lock to ensure the storage engine is not shutdown
-            Lock::GlobalLock global(txn->lockState(), MODE_IS, UINT_MAX);
+            Lock::GlobalLock global(opCtx->lockState(), MODE_IS, UINT_MAX);
             StorageEngine* storageEngine = getGlobalServiceContext()->getGlobalStorageEngine();
-            result.append("numFiles", storageEngine->flushAllFiles(txn, sync));
+            result.append("numFiles", storageEngine->flushAllFiles(opCtx, sync));
             return true;
         }
 
-        Lock::ExclusiveLock lk(txn->lockState(), commandMutex);
+        Lock::ExclusiveLock lk(opCtx->lockState(), commandMutex);
         if (!sync) {
             errmsg = "fsync: sync option must be true when using lock";
             return false;
@@ -292,7 +292,7 @@ public:
         return isAuthorized ? Status::OK() : Status(ErrorCodes::Unauthorized, "Unauthorized");
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const std::string& db,
              BSONObj& cmdObj,
              int options,
@@ -300,7 +300,7 @@ public:
              BSONObjBuilder& result) override {
         log() << "command: unlock requested";
 
-        Lock::ExclusiveLock lk(txn->lockState(), commandMutex);
+        Lock::ExclusiveLock lk(opCtx->lockState(), commandMutex);
 
         if (unlockFsync()) {
             const auto lockCount = fsyncCmd.getLockCount();
@@ -343,26 +343,26 @@ void FSyncLockThread::run() {
     invariant(fsyncCmd.getLockCount_inLock() == 1);
 
     try {
-        const ServiceContext::UniqueOperationContext txnPtr = cc().makeOperationContext();
-        OperationContext& txn = *txnPtr;
-        ScopedTransaction transaction(&txn, MODE_X);
-        Lock::GlobalWrite global(txn.lockState());  // No WriteUnitOfWork needed
+        const ServiceContext::UniqueOperationContext opCtxPtr = cc().makeOperationContext();
+        OperationContext& opCtx = *opCtxPtr;
+        ScopedTransaction transaction(&opCtx, MODE_X);
+        Lock::GlobalWrite global(opCtx.lockState());  // No WriteUnitOfWork needed
 
         try {
             // TODO SERVER-26822: Replace MMAPv1 specific calls with ones that are storage engine
             // agnostic.
-            getDur().syncDataAndTruncateJournal(&txn);
+            getDur().syncDataAndTruncateJournal(&opCtx);
         } catch (const std::exception& e) {
             error() << "error doing syncDataAndTruncateJournal: " << e.what();
             fsyncCmd.threadStatus = Status(ErrorCodes::CommandFailed, e.what());
             fsyncCmd.acquireFsyncLockSyncCV.notify_one();
             return;
         }
-        txn.lockState()->downgradeGlobalXtoSForMMAPV1();
+        opCtx.lockState()->downgradeGlobalXtoSForMMAPV1();
         StorageEngine* storageEngine = getGlobalServiceContext()->getGlobalStorageEngine();
 
         try {
-            storageEngine->flushAllFiles(&txn, true);
+            storageEngine->flushAllFiles(&opCtx, true);
         } catch (const std::exception& e) {
             error() << "error doing flushAll: " << e.what();
             fsyncCmd.threadStatus = Status(ErrorCodes::CommandFailed, e.what());
@@ -371,9 +371,9 @@ void FSyncLockThread::run() {
         }
         try {
             MONGO_WRITE_CONFLICT_RETRY_LOOP_BEGIN {
-                uassertStatusOK(storageEngine->beginBackup(&txn));
+                uassertStatusOK(storageEngine->beginBackup(&opCtx));
             }
-            MONGO_WRITE_CONFLICT_RETRY_LOOP_END(&txn, "beginBackup", "global");
+            MONGO_WRITE_CONFLICT_RETRY_LOOP_END(&opCtx, "beginBackup", "global");
         } catch (const DBException& e) {
             error() << "storage engine unable to begin backup : " << e.toString();
             fsyncCmd.threadStatus = e.toStatus();
@@ -388,7 +388,7 @@ void FSyncLockThread::run() {
             fsyncCmd.releaseFsyncLockSyncCV.wait(lk);
         }
 
-        storageEngine->endBackup(&txn);
+        storageEngine->endBackup(&opCtx);
 
     } catch (const std::exception& e) {
         severe() << "FSyncLockThread exception: " << e.what();
diff --git a/src/mongo/db/commands/generic.cpp b/src/mongo/db/commands/generic.cpp
index f554498bfbf..f58179be389 100644
--- a/src/mongo/db/commands/generic.cpp
+++ b/src/mongo/db/commands/generic.cpp
@@ -88,7 +88,7 @@ public:
         help << "{ buildinfo:1 }";
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const std::string& dbname,
              BSONObj& jsobj,
              int,  // options
@@ -118,7 +118,7 @@ public:
     virtual void addRequiredPrivileges(const std::string& dbname,
                                        const BSONObj& cmdObj,
                                        std::vector<Privilege>* out) {}  // No auth required
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const string& badns,
                      BSONObj& cmdObj,
                      int,
@@ -144,7 +144,7 @@ public:
     virtual void addRequiredPrivileges(const std::string& dbname,
                                        const BSONObj& cmdObj,
                                        std::vector<Privilege>* out) {}  // No auth required
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const string& ns,
                      BSONObj& cmdObj,
                      int,
@@ -187,7 +187,7 @@ public:
         actions.addAction(ActionType::hostInfo);
         out->push_back(Privilege(ResourcePattern::forClusterResource(), actions));
     }
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int,
@@ -235,7 +235,7 @@ public:
         actions.addAction(ActionType::logRotate);
         out->push_back(Privilege(ResourcePattern::forClusterResource(), actions));
     }
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const string& ns,
                      BSONObj& cmdObj,
                      int,
@@ -267,7 +267,7 @@ public:
     virtual void addRequiredPrivileges(const std::string& dbname,
                                        const BSONObj& cmdObj,
                                        std::vector<Privilege>* out) {}  // No auth required
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const string& ns,
                      BSONObj& cmdObj,
                      int,
@@ -366,7 +366,7 @@ public:
                                        const BSONObj& cmdObj,
                                        std::vector<Privilege>* out) {}  // No auth required
     CmdForceError() : Command("forceerror") {}
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbnamne,
              BSONObj& cmdObj,
              int,
@@ -401,7 +401,7 @@ public:
         help << "{ getLog : '*' }  OR { getLog : 'global' }";
     }
 
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const string& dbname,
                      BSONObj& cmdObj,
                      int,
@@ -471,7 +471,7 @@ public:
         actions.addAction(ActionType::getCmdLineOpts);
         out->push_back(Privilege(ResourcePattern::forClusterResource(), actions));
     }
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const string&,
                      BSONObj& cmdObj,
                      int,
diff --git a/src/mongo/db/commands/geo_near_cmd.cpp b/src/mongo/db/commands/geo_near_cmd.cpp
index 159feb2e74f..3c26005121b 100644
--- a/src/mongo/db/commands/geo_near_cmd.cpp
+++ b/src/mongo/db/commands/geo_near_cmd.cpp
@@ -99,7 +99,7 @@ public:
         out->push_back(Privilege(parseResourcePattern(dbname, cmdObj), actions));
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int,
@@ -111,7 +111,7 @@ public:
         }
 
         const NamespaceString nss(parseNsCollectionRequired(dbname, cmdObj));
-        AutoGetCollectionForRead ctx(txn, nss);
+        AutoGetCollectionForRead ctx(opCtx, nss);
 
         Collection* collection = ctx.getCollection();
         if (!collection) {
@@ -126,7 +126,8 @@ public:
         // We seek to populate this.
         string nearFieldName;
         bool using2DIndex = false;
-        if (!getFieldName(txn, collection, indexCatalog, &nearFieldName, &errmsg, &using2DIndex)) {
+        if (!getFieldName(
+                opCtx, collection, indexCatalog, &nearFieldName, &errmsg, &using2DIndex)) {
             return false;
         }
 
@@ -224,8 +225,8 @@ public:
         qr->setProj(projObj);
         qr->setLimit(numWanted);
         qr->setCollation(collation);
-        const ExtensionsCallbackReal extensionsCallback(txn, &nss);
-        auto statusWithCQ = CanonicalQuery::canonicalize(txn, std::move(qr), extensionsCallback);
+        const ExtensionsCallbackReal extensionsCallback(opCtx, &nss);
+        auto statusWithCQ = CanonicalQuery::canonicalize(opCtx, std::move(qr), extensionsCallback);
         if (!statusWithCQ.isOK()) {
             errmsg = "Can't parse filter / create query";
             return false;
@@ -237,7 +238,7 @@ public:
         RangePreserver preserver(collection);
 
         auto statusWithPlanExecutor =
-            getExecutor(txn, collection, std::move(cq), PlanExecutor::YIELD_AUTO, 0);
+            getExecutor(opCtx, collection, std::move(cq), PlanExecutor::YIELD_AUTO, 0);
         if (!statusWithPlanExecutor.isOK()) {
             errmsg = "can't get query executor";
             return false;
@@ -245,9 +246,9 @@ public:
 
         unique_ptr<PlanExecutor> exec = std::move(statusWithPlanExecutor.getValue());
 
-        auto curOp = CurOp::get(txn);
+        auto curOp = CurOp::get(opCtx);
         {
-            stdx::lock_guard<Client> lk(*txn->getClient());
+            stdx::lock_guard<Client> lk(*opCtx->getClient());
             curOp->setPlanSummary_inlock(Explain::getPlanSummary(exec.get()));
         }
 
@@ -334,7 +335,7 @@ public:
         stats.appendIntOrLL("time", curOp->elapsedMicros() / 1000);
         stats.done();
 
-        collection->infoCache()->notifyOfQuery(txn, summary.indexesUsed);
+        collection->infoCache()->notifyOfQuery(opCtx, summary.indexesUsed);
 
         curOp->debug().setPlanSummaryMetrics(summary);
 
@@ -348,7 +349,7 @@ public:
     }
 
 private:
-    bool getFieldName(OperationContext* txn,
+    bool getFieldName(OperationContext* opCtx,
                       Collection* collection,
                       IndexCatalog* indexCatalog,
                       string* fieldOut,
@@ -357,7 +358,7 @@ private:
         vector<IndexDescriptor*> idxs;
 
         // First, try 2d.
-        collection->getIndexCatalog()->findIndexByType(txn, IndexNames::GEO_2D, idxs);
+        collection->getIndexCatalog()->findIndexByType(opCtx, IndexNames::GEO_2D, idxs);
         if (idxs.size() > 1) {
             *errOut = "more than one 2d index, not sure which to run geoNear on";
             return false;
@@ -378,7 +379,7 @@ private:
 
         // Next, 2dsphere.
         idxs.clear();
-        collection->getIndexCatalog()->findIndexByType(txn, IndexNames::GEO_2DSPHERE, idxs);
+        collection->getIndexCatalog()->findIndexByType(opCtx, IndexNames::GEO_2DSPHERE, idxs);
         if (0 == idxs.size()) {
             *errOut = "no geo indices for geoNear";
             return false;
diff --git a/src/mongo/db/commands/get_last_error.cpp b/src/mongo/db/commands/get_last_error.cpp
index e71dcf15210..0340a01139b 100644
--- a/src/mongo/db/commands/get_last_error.cpp
+++ b/src/mongo/db/commands/get_last_error.cpp
@@ -70,13 +70,13 @@ public:
         help << "reset error state (used with getpreverror)";
     }
     CmdResetError() : Command("resetError", false, "reseterror") {}
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& db,
              BSONObj& cmdObj,
              int,
              string& errmsg,
              BSONObjBuilder& result) {
-        LastError::get(txn->getClient()).reset();
+        LastError::get(opCtx->getClient()).reset();
         return true;
     }
 } cmdResetError;
@@ -104,7 +104,7 @@ public:
              << "  { wtimeout:m} - timeout for w in m milliseconds";
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int,
@@ -134,11 +134,11 @@ public:
         // err is null.
         //
 
-        LastError* le = &LastError::get(txn->getClient());
+        LastError* le = &LastError::get(opCtx->getClient());
         le->disable();
 
         // Always append lastOp and connectionId
-        Client& c = *txn->getClient();
+        Client& c = *opCtx->getClient();
         auto replCoord = repl::getGlobalReplicationCoordinator();
         if (replCoord->getReplicationMode() == repl::ReplicationCoordinator::modeReplSet) {
             const repl::OpTime lastOp = repl::ReplClientInfo::forClient(c).getLastOp();
@@ -224,7 +224,7 @@ public:
             // Ensure options are valid for this host. Since getLastError doesn't do writes itself,
             // treat it as if these are admin database writes, which need to be replicated so we do
             // the strictest checks write concern checks.
-            status = validateWriteConcern(txn, writeConcern, NamespaceString::kAdminDb);
+            status = validateWriteConcern(opCtx, writeConcern, NamespaceString::kAdminDb);
         }
 
         if (!status.isOK()) {
@@ -267,12 +267,12 @@ public:
         }
 
         {
-            stdx::lock_guard<Client> lk(*txn->getClient());
-            txn->setMessage_inlock("waiting for write concern");
+            stdx::lock_guard<Client> lk(*opCtx->getClient());
+            opCtx->setMessage_inlock("waiting for write concern");
         }
 
         WriteConcernResult wcResult;
-        status = waitForWriteConcern(txn, lastOpTime, writeConcern, &wcResult);
+        status = waitForWriteConcern(opCtx, lastOpTime, writeConcern, &wcResult);
         wcResult.appendTo(writeConcern, &result);
 
         // For backward compatibility with 2.4, wtimeout returns ok : 1.0
@@ -305,13 +305,13 @@ public:
                                        const BSONObj& cmdObj,
                                        std::vector<Privilege>* out) {}  // No auth required
     CmdGetPrevError() : Command("getPrevError", false, "getpreverror") {}
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int,
              string& errmsg,
              BSONObjBuilder& result) {
-        LastError* le = &LastError::get(txn->getClient());
+        LastError* le = &LastError::get(opCtx->getClient());
         le->disable();
         le->appendSelf(result, true);
         if (le->isValid())
diff --git a/src/mongo/db/commands/getmore_cmd.cpp b/src/mongo/db/commands/getmore_cmd.cpp
index 4bedfe06e01..ed4b43a81a2 100644
--- a/src/mongo/db/commands/getmore_cmd.cpp
+++ b/src/mongo/db/commands/getmore_cmd.cpp
@@ -144,23 +144,23 @@ public:
             request.nss, request.cursorid, request.term.is_initialized());
     }
 
-    bool runParsed(OperationContext* txn,
+    bool runParsed(OperationContext* opCtx,
                    const NamespaceString& origNss,
                    const GetMoreRequest& request,
                    BSONObj& cmdObj,
                    std::string& errmsg,
                    BSONObjBuilder& result) {
 
-        auto curOp = CurOp::get(txn);
+        auto curOp = CurOp::get(opCtx);
         curOp->debug().cursorid = request.cursorid;
 
         // Disable shard version checking - getmore commands are always unversioned
-        OperationShardingState::get(txn).setShardVersion(request.nss, ChunkVersion::IGNORED());
+        OperationShardingState::get(opCtx).setShardVersion(request.nss, ChunkVersion::IGNORED());
 
         // Validate term before acquiring locks, if provided.
         if (request.term) {
-            auto replCoord = repl::ReplicationCoordinator::get(txn);
-            Status status = replCoord->updateTerm(txn, *request.term);
+            auto replCoord = repl::ReplicationCoordinator::get(opCtx);
+            Status status = replCoord->updateTerm(opCtx, *request.term);
             // Note: updateTerm returns ok if term stayed the same.
             if (!status.isOK()) {
                 return appendCommandStatus(result, status);
@@ -193,7 +193,7 @@ public:
         if (request.nss.isListIndexesCursorNS() || request.nss.isListCollectionsCursorNS()) {
             cursorManager = CursorManager::getGlobalCursorManager();
         } else {
-            ctx = stdx::make_unique<AutoGetCollectionOrViewForRead>(txn, request.nss);
+            ctx = stdx::make_unique<AutoGetCollectionOrViewForRead>(opCtx, request.nss);
             auto viewCtx = static_cast<AutoGetCollectionOrViewForRead*>(ctx.get());
             Collection* collection = ctx->getCollection();
             if (!collection) {
@@ -202,7 +202,7 @@ public:
                 // unknown, resulting in an appropriate error.
                 if (viewCtx->getView()) {
                     auto resolved =
-                        viewCtx->getDb()->getViewCatalog()->resolveView(txn, request.nss);
+                        viewCtx->getDb()->getViewCatalog()->resolveView(opCtx, request.nss);
                     if (!resolved.isOK()) {
                         return appendCommandStatus(result, resolved.getStatus());
                     }
@@ -210,7 +210,7 @@ public:
 
                     // Only one shardversion can be set at a time for an operation, so unset it
                     // here to allow setting it on the underlying namespace.
-                    OperationShardingState::get(txn).unsetShardVersion(request.nss);
+                    OperationShardingState::get(opCtx).unsetShardVersion(request.nss);
 
                     GetMoreRequest newRequest(resolved.getValue().getNamespace(),
                                               request.cursorid,
@@ -219,11 +219,11 @@ public:
                                               request.term,
                                               request.lastKnownCommittedOpTime);
 
-                    bool retVal = runParsed(txn, origNss, newRequest, cmdObj, errmsg, result);
+                    bool retVal = runParsed(opCtx, origNss, newRequest, cmdObj, errmsg, result);
                     {
                         // Set the namespace of the curop back to the view namespace so ctx records
                         // stats on this view namespace on destruction.
-                        stdx::lock_guard<Client> lk(*txn->getClient());
+                        stdx::lock_guard<Client> lk(*opCtx->getClient());
                         curOp->setNS_inlock(origNss.ns());
                     }
                     return retVal;
@@ -251,7 +251,7 @@ public:
             invariant(!unpinCollLock);
             sleepFor(Milliseconds(10));
             ctx.reset();
-            ctx = stdx::make_unique<AutoGetCollectionForRead>(txn, request.nss);
+            ctx = stdx::make_unique<AutoGetCollectionForRead>(opCtx, request.nss);
         }
 
         if (request.nss.ns() != cursor->ns()) {
@@ -289,15 +289,15 @@ public:
 
         // On early return, get rid of the cursor.
         ScopeGuard cursorFreer =
-            MakeGuard(&GetMoreCmd::cleanupCursor, txn, &ccPin.getValue(), request);
+            MakeGuard(&GetMoreCmd::cleanupCursor, opCtx, &ccPin.getValue(), request);
 
         if (cursor->isReadCommitted())
-            uassertStatusOK(txn->recoveryUnit()->setReadFromMajorityCommittedSnapshot());
+            uassertStatusOK(opCtx->recoveryUnit()->setReadFromMajorityCommittedSnapshot());
 
         // Reset timeout timer on the cursor since the cursor is still in use.
         cursor->resetIdleTime();
 
-        const bool hasOwnMaxTime = txn->hasDeadline();
+        const bool hasOwnMaxTime = opCtx->hasDeadline();
 
         if (!hasOwnMaxTime) {
             // There is no time limit set directly on this getMore command. If the cursor is
@@ -307,16 +307,16 @@ public:
             if (isCursorAwaitData(cursor)) {
                 uassert(40117,
                         "Illegal attempt to set operation deadline within DBDirectClient",
-                        !txn->getClient()->isInDirectClient());
-                txn->setDeadlineAfterNowBy(Seconds{1});
+                        !opCtx->getClient()->isInDirectClient());
+                opCtx->setDeadlineAfterNowBy(Seconds{1});
             } else if (cursor->getLeftoverMaxTimeMicros() < Microseconds::max()) {
                 uassert(40118,
                         "Illegal attempt to set operation deadline within DBDirectClient",
-                        !txn->getClient()->isInDirectClient());
-                txn->setDeadlineAfterNowBy(cursor->getLeftoverMaxTimeMicros());
+                        !opCtx->getClient()->isInDirectClient());
+                opCtx->setDeadlineAfterNowBy(cursor->getLeftoverMaxTimeMicros());
             }
         }
-        txn->checkForInterrupt();  // May trigger maxTimeAlwaysTimeOut fail point.
+        opCtx->checkForInterrupt();  // May trigger maxTimeAlwaysTimeOut fail point.
 
         if (cursor->isAggCursor()) {
             // Agg cursors handle their own locking internally.
@@ -324,12 +324,12 @@ public:
         }
 
         PlanExecutor* exec = cursor->getExecutor();
-        exec->reattachToOperationContext(txn);
+        exec->reattachToOperationContext(opCtx);
         exec->restoreState();
 
         auto planSummary = Explain::getPlanSummary(exec);
         {
-            stdx::lock_guard<Client> lk(*txn->getClient());
+            stdx::lock_guard<Client> lk(*opCtx->getClient());
             curOp->setPlanSummary_inlock(planSummary);
 
             // Ensure that the original query or command object is available in the slow query log,
@@ -378,7 +378,7 @@ public:
         // If this is an await data cursor, and we hit EOF without generating any results, then
         // we block waiting for new data to arrive.
         if (isCursorAwaitData(cursor) && state == PlanExecutor::IS_EOF && numResults == 0) {
-            auto replCoord = repl::ReplicationCoordinator::get(txn);
+            auto replCoord = repl::ReplicationCoordinator::get(opCtx);
             // Return immediately if we need to update the commit time.
             if (!request.lastKnownCommittedOpTime ||
                 (request.lastKnownCommittedOpTime == replCoord->getLastCommittedOpTime())) {
@@ -393,7 +393,7 @@ public:
                 ctx.reset();
 
                 // Block waiting for data.
-                const auto timeout = txn->getRemainingMaxTimeMicros();
+                const auto timeout = opCtx->getRemainingMaxTimeMicros();
                 notifier->wait(notifierVersion, timeout);
                 notifier.reset();
 
@@ -402,7 +402,7 @@ public:
                 // CappedInsertNotifier.
                 curOp->setExpectedLatencyMs(durationCount<Milliseconds>(timeout));
 
-                ctx.reset(new AutoGetCollectionForRead(txn, request.nss));
+                ctx.reset(new AutoGetCollectionForRead(opCtx, request.nss));
                 exec->restoreState();
 
                 // We woke up because either the timed_wait expired, or there was more data. Either
@@ -440,7 +440,7 @@ public:
             // from a previous find, then don't roll remaining micros over to the next
             // getMore.
             if (!hasOwnMaxTime) {
-                cursor->setLeftoverMaxTimeMicros(txn->getRemainingMaxTimeMicros());
+                cursor->setLeftoverMaxTimeMicros(opCtx->getRemainingMaxTimeMicros());
             }
 
             cursor->incPos(numResults);
@@ -463,16 +463,16 @@ public:
             // earlier and need to reacquire it in order to clean up our ClientCursorPin.
             if (cursor->isAggCursor()) {
                 invariant(NULL == ctx.get());
-                unpinDBLock.reset(new Lock::DBLock(txn->lockState(), request.nss.db(), MODE_IS));
+                unpinDBLock.reset(new Lock::DBLock(opCtx->lockState(), request.nss.db(), MODE_IS));
                 unpinCollLock.reset(
-                    new Lock::CollectionLock(txn->lockState(), request.nss.ns(), MODE_IS));
+                    new Lock::CollectionLock(opCtx->lockState(), request.nss.ns(), MODE_IS));
             }
         }
 
         return true;
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const std::string& dbname,
              BSONObj& cmdObj,
              int options,
@@ -481,7 +481,7 @@ public:
         // Counted as a getMore, not as a command.
         globalOpCounters.gotGetMore();
 
-        if (txn->getClient()->isInDirectClient()) {
+        if (opCtx->getClient()->isInDirectClient()) {
             return appendCommandStatus(
                 result,
                 Status(ErrorCodes::IllegalOperation, "Cannot run getMore command from eval()"));
@@ -492,7 +492,7 @@ public:
             return appendCommandStatus(result, parsedRequest.getStatus());
         }
         auto request = parsedRequest.getValue();
-        return runParsed(txn, request.nss, request, cmdObj, errmsg, result);
+        return runParsed(opCtx, request.nss, request, cmdObj, errmsg, result);
     }
 
     /**
@@ -558,7 +558,7 @@ public:
      * Called via a ScopeGuard on early return in order to ensure that the ClientCursor gets
      * cleaned up properly.
      */
-    static void cleanupCursor(OperationContext* txn,
+    static void cleanupCursor(OperationContext* opCtx,
                               ClientCursorPin* ccPin,
                               const GetMoreRequest& request) {
         ClientCursor* cursor = ccPin->getCursor();
@@ -567,9 +567,9 @@ public:
         std::unique_ptr<Lock::CollectionLock> unpinCollLock;
 
         if (cursor->isAggCursor()) {
-            unpinDBLock.reset(new Lock::DBLock(txn->lockState(), request.nss.db(), MODE_IS));
+            unpinDBLock.reset(new Lock::DBLock(opCtx->lockState(), request.nss.db(), MODE_IS));
             unpinCollLock.reset(
-                new Lock::CollectionLock(txn->lockState(), request.nss.ns(), MODE_IS));
+                new Lock::CollectionLock(opCtx->lockState(), request.nss.ns(), MODE_IS));
         }
 
         ccPin->deleteUnderlying();
diff --git a/src/mongo/db/commands/group_cmd.cpp b/src/mongo/db/commands/group_cmd.cpp
index 8d91be1f920..cf42c368e75 100644
--- a/src/mongo/db/commands/group_cmd.cpp
+++ b/src/mongo/db/commands/group_cmd.cpp
@@ -120,7 +120,7 @@ private:
         return nss.ns();
     }
 
-    virtual Status explain(OperationContext* txn,
+    virtual Status explain(OperationContext* opCtx,
                            const std::string& dbname,
                            const BSONObj& cmdObj,
                            ExplainCommon::Verbosity verbosity,
@@ -134,11 +134,11 @@ private:
 
         groupRequest.explain = true;
 
-        AutoGetCollectionForRead ctx(txn, groupRequest.ns);
+        AutoGetCollectionForRead ctx(opCtx, groupRequest.ns);
         Collection* coll = ctx.getCollection();
 
         auto statusWithPlanExecutor =
-            getExecutorGroup(txn, coll, groupRequest, PlanExecutor::YIELD_AUTO);
+            getExecutorGroup(opCtx, coll, groupRequest, PlanExecutor::YIELD_AUTO);
         if (!statusWithPlanExecutor.isOK()) {
             return statusWithPlanExecutor.getStatus();
         }
@@ -149,7 +149,7 @@ private:
         return Status::OK();
     }
 
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const std::string& dbname,
                      BSONObj& cmdObj,
                      int options,
@@ -166,20 +166,20 @@ private:
             return appendCommandStatus(result, parseRequestStatus);
         }
 
-        AutoGetCollectionForRead ctx(txn, groupRequest.ns);
+        AutoGetCollectionForRead ctx(opCtx, groupRequest.ns);
         Collection* coll = ctx.getCollection();
 
         auto statusWithPlanExecutor =
-            getExecutorGroup(txn, coll, groupRequest, PlanExecutor::YIELD_AUTO);
+            getExecutorGroup(opCtx, coll, groupRequest, PlanExecutor::YIELD_AUTO);
         if (!statusWithPlanExecutor.isOK()) {
             return appendCommandStatus(result, statusWithPlanExecutor.getStatus());
         }
 
         unique_ptr<PlanExecutor> planExecutor = std::move(statusWithPlanExecutor.getValue());
 
-        auto curOp = CurOp::get(txn);
+        auto curOp = CurOp::get(opCtx);
         {
-            stdx::lock_guard<Client> lk(*txn->getClient());
+            stdx::lock_guard<Client> lk(*opCtx->getClient());
             curOp->setPlanSummary_inlock(Explain::getPlanSummary(planExecutor.get()));
         }
 
@@ -204,7 +204,7 @@ private:
         PlanSummaryStats summaryStats;
         Explain::getSummaryStats(*planExecutor, &summaryStats);
         if (coll) {
-            coll->infoCache()->notifyOfQuery(txn, summaryStats.indexesUsed);
+            coll->infoCache()->notifyOfQuery(opCtx, summaryStats.indexesUsed);
         }
         curOp->debug().setPlanSummaryMetrics(summaryStats);
 
diff --git a/src/mongo/db/commands/hashcmd.cpp b/src/mongo/db/commands/hashcmd.cpp
index 76c1960f804..f7e54703898 100644
--- a/src/mongo/db/commands/hashcmd.cpp
+++ b/src/mongo/db/commands/hashcmd.cpp
@@ -79,7 +79,7 @@ public:
      *>  "out" : NumberLong(6271151123721111923),
      *>  "ok" : 1 }
      **/
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& db,
              BSONObj& cmdObj,
              int options,
diff --git a/src/mongo/db/commands/haystack.cpp b/src/mongo/db/commands/haystack.cpp
index dc44fef0e1d..d760ee9b866 100644
--- a/src/mongo/db/commands/haystack.cpp
+++ b/src/mongo/db/commands/haystack.cpp
@@ -95,7 +95,7 @@ public:
         out->push_back(Privilege(parseResourcePattern(dbname, cmdObj), actions));
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int,
@@ -103,7 +103,7 @@ public:
              BSONObjBuilder& result) {
         const NamespaceString nss = parseNsCollectionRequired(dbname, cmdObj);
 
-        AutoGetCollectionForRead ctx(txn, nss);
+        AutoGetCollectionForRead ctx(opCtx, nss);
 
         Collection* collection = ctx.getCollection();
         if (!collection) {
@@ -112,7 +112,7 @@ public:
         }
 
         vector<IndexDescriptor*> idxs;
-        collection->getIndexCatalog()->findIndexByType(txn, IndexNames::GEO_HAYSTACK, idxs);
+        collection->getIndexCatalog()->findIndexByType(opCtx, IndexNames::GEO_HAYSTACK, idxs);
         if (idxs.size() == 0) {
             errmsg = "no geoSearch index";
             return false;
@@ -137,7 +137,7 @@ public:
         IndexDescriptor* desc = idxs[0];
         HaystackAccessMethod* ham =
             static_cast<HaystackAccessMethod*>(collection->getIndexCatalog()->getIndex(desc));
-        ham->searchCommand(txn,
+        ham->searchCommand(opCtx,
                            collection,
                            nearElt.Obj(),
                            maxDistance.numberDouble(),
diff --git a/src/mongo/db/commands/index_filter_commands.cpp b/src/mongo/db/commands/index_filter_commands.cpp
index 3ec63ba635c..68230d587af 100644
--- a/src/mongo/db/commands/index_filter_commands.cpp
+++ b/src/mongo/db/commands/index_filter_commands.cpp
@@ -61,7 +61,7 @@ using namespace mongo;
 /**
  * Retrieves a collection's query settings and plan cache from the database.
  */
-static Status getQuerySettingsAndPlanCache(OperationContext* txn,
+static Status getQuerySettingsAndPlanCache(OperationContext* opCtx,
                                            Collection* collection,
                                            const string& ns,
                                            QuerySettings** querySettingsOut,
@@ -115,14 +115,14 @@ using std::unique_ptr;
 IndexFilterCommand::IndexFilterCommand(const string& name, const string& helpText)
     : Command(name), helpText(helpText) {}
 
-bool IndexFilterCommand::run(OperationContext* txn,
+bool IndexFilterCommand::run(OperationContext* opCtx,
                              const string& dbname,
                              BSONObj& cmdObj,
                              int options,
                              string& errmsg,
                              BSONObjBuilder& result) {
     const NamespaceString nss(parseNsCollectionRequired(dbname, cmdObj));
-    Status status = runIndexFilterCommand(txn, nss.ns(), cmdObj, &result);
+    Status status = runIndexFilterCommand(opCtx, nss.ns(), cmdObj, &result);
     return appendCommandStatus(result, status);
 }
 
@@ -160,17 +160,17 @@ ListFilters::ListFilters()
     : IndexFilterCommand("planCacheListFilters",
                          "Displays index filters for all query shapes in a collection.") {}
 
-Status ListFilters::runIndexFilterCommand(OperationContext* txn,
+Status ListFilters::runIndexFilterCommand(OperationContext* opCtx,
                                           const string& ns,
                                           BSONObj& cmdObj,
                                           BSONObjBuilder* bob) {
     // This is a read lock. The query settings is owned by the collection.
-    AutoGetCollectionForRead ctx(txn, NamespaceString(ns));
+    AutoGetCollectionForRead ctx(opCtx, NamespaceString(ns));
 
     QuerySettings* querySettings;
     PlanCache* unused;
     Status status =
-        getQuerySettingsAndPlanCache(txn, ctx.getCollection(), ns, &querySettings, &unused);
+        getQuerySettingsAndPlanCache(opCtx, ctx.getCollection(), ns, &querySettings, &unused);
     if (!status.isOK()) {
         // No collection - return empty array of filters.
         BSONArrayBuilder hintsBuilder(bob->subarrayStart("filters"));
@@ -228,26 +228,26 @@ ClearFilters::ClearFilters()
                          "Clears index filter for a single query shape or, "
                          "if the query shape is omitted, all filters for the collection.") {}
 
-Status ClearFilters::runIndexFilterCommand(OperationContext* txn,
+Status ClearFilters::runIndexFilterCommand(OperationContext* opCtx,
                                            const std::string& ns,
                                            BSONObj& cmdObj,
                                            BSONObjBuilder* bob) {
     // This is a read lock. The query settings is owned by the collection.
-    AutoGetCollectionForRead ctx(txn, NamespaceString(ns));
+    AutoGetCollectionForRead ctx(opCtx, NamespaceString(ns));
 
     QuerySettings* querySettings;
     PlanCache* planCache;
     Status status =
-        getQuerySettingsAndPlanCache(txn, ctx.getCollection(), ns, &querySettings, &planCache);
+        getQuerySettingsAndPlanCache(opCtx, ctx.getCollection(), ns, &querySettings, &planCache);
     if (!status.isOK()) {
         // No collection - do nothing.
         return Status::OK();
     }
-    return clear(txn, querySettings, planCache, ns, cmdObj);
+    return clear(opCtx, querySettings, planCache, ns, cmdObj);
 }
 
 // static
-Status ClearFilters::clear(OperationContext* txn,
+Status ClearFilters::clear(OperationContext* opCtx,
                            QuerySettings* querySettings,
                            PlanCache* planCache,
                            const std::string& ns,
@@ -259,7 +259,7 @@ Status ClearFilters::clear(OperationContext* txn,
     // - clear hints for single query shape when a query shape is described in the
     //   command arguments.
     if (cmdObj.hasField("query")) {
-        auto statusWithCQ = PlanCacheCommand::canonicalize(txn, ns, cmdObj);
+        auto statusWithCQ = PlanCacheCommand::canonicalize(opCtx, ns, cmdObj);
         if (!statusWithCQ.isOK()) {
             return statusWithCQ.getStatus();
         }
@@ -291,7 +291,7 @@ Status ClearFilters::clear(OperationContext* txn,
     querySettings->clearAllowedIndices();
 
     const NamespaceString nss(ns);
-    const ExtensionsCallbackReal extensionsCallback(txn, &nss);
+    const ExtensionsCallbackReal extensionsCallback(opCtx, &nss);
 
     // Remove corresponding entries from plan cache.
     // Admin hints affect the planning process directly. If there were
@@ -312,7 +312,7 @@ Status ClearFilters::clear(OperationContext* txn,
         qr->setSort(entry.sort);
         qr->setProj(entry.projection);
         qr->setCollation(entry.collation);
-        auto statusWithCQ = CanonicalQuery::canonicalize(txn, std::move(qr), extensionsCallback);
+        auto statusWithCQ = CanonicalQuery::canonicalize(opCtx, std::move(qr), extensionsCallback);
         invariantOK(statusWithCQ.getStatus());
         std::unique_ptr<CanonicalQuery> cq = std::move(statusWithCQ.getValue());
 
@@ -329,26 +329,26 @@ SetFilter::SetFilter()
     : IndexFilterCommand("planCacheSetFilter",
                          "Sets index filter for a query shape. Overrides existing filter.") {}
 
-Status SetFilter::runIndexFilterCommand(OperationContext* txn,
+Status SetFilter::runIndexFilterCommand(OperationContext* opCtx,
                                         const std::string& ns,
                                         BSONObj& cmdObj,
                                         BSONObjBuilder* bob) {
     // This is a read lock. The query settings is owned by the collection.
     const NamespaceString nss(ns);
-    AutoGetCollectionForRead ctx(txn, nss);
+    AutoGetCollectionForRead ctx(opCtx, nss);
 
     QuerySettings* querySettings;
     PlanCache* planCache;
     Status status =
-        getQuerySettingsAndPlanCache(txn, ctx.getCollection(), ns, &querySettings, &planCache);
+        getQuerySettingsAndPlanCache(opCtx, ctx.getCollection(), ns, &querySettings, &planCache);
     if (!status.isOK()) {
         return status;
     }
-    return set(txn, querySettings, planCache, ns, cmdObj);
+    return set(opCtx, querySettings, planCache, ns, cmdObj);
 }
 
 // static
-Status SetFilter::set(OperationContext* txn,
+Status SetFilter::set(OperationContext* opCtx,
                       QuerySettings* querySettings,
                       PlanCache* planCache,
                       const string& ns,
@@ -385,7 +385,7 @@ Status SetFilter::set(OperationContext* txn,
         }
     }
 
-    auto statusWithCQ = PlanCacheCommand::canonicalize(txn, ns, cmdObj);
+    auto statusWithCQ = PlanCacheCommand::canonicalize(opCtx, ns, cmdObj);
     if (!statusWithCQ.isOK()) {
         return statusWithCQ.getStatus();
     }
diff --git a/src/mongo/db/commands/index_filter_commands.h b/src/mongo/db/commands/index_filter_commands.h
index c34494b19d8..1fada8269a5 100644
--- a/src/mongo/db/commands/index_filter_commands.h
+++ b/src/mongo/db/commands/index_filter_commands.h
@@ -63,7 +63,7 @@ public:
      * implement plan cache command functionality.
      */
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const std::string& dbname,
              BSONObj& cmdObj,
              int options,
@@ -92,7 +92,7 @@ public:
      * Should contain just enough logic to invoke run*Command() function
      * in query_settings.h
      */
-    virtual Status runIndexFilterCommand(OperationContext* txn,
+    virtual Status runIndexFilterCommand(OperationContext* opCtx,
                                          const std::string& ns,
                                          BSONObj& cmdObj,
                                          BSONObjBuilder* bob) = 0;
@@ -111,7 +111,7 @@ class ListFilters : public IndexFilterCommand {
 public:
     ListFilters();
 
-    virtual Status runIndexFilterCommand(OperationContext* txn,
+    virtual Status runIndexFilterCommand(OperationContext* opCtx,
                                          const std::string& ns,
                                          BSONObj& cmdObj,
                                          BSONObjBuilder* bob);
@@ -133,7 +133,7 @@ class ClearFilters : public IndexFilterCommand {
 public:
     ClearFilters();
 
-    virtual Status runIndexFilterCommand(OperationContext* txn,
+    virtual Status runIndexFilterCommand(OperationContext* opCtx,
                                          const std::string& ns,
                                          BSONObj& cmdObj,
                                          BSONObjBuilder* bob);
@@ -144,7 +144,7 @@ public:
      * Namespace argument ns is ignored if we are clearing the entire cache.
      * Removes corresponding entries from plan cache.
      */
-    static Status clear(OperationContext* txn,
+    static Status clear(OperationContext* opCtx,
                         QuerySettings* querySettings,
                         PlanCache* planCache,
                         const std::string& ns,
@@ -167,7 +167,7 @@ class SetFilter : public IndexFilterCommand {
 public:
     SetFilter();
 
-    virtual Status runIndexFilterCommand(OperationContext* txn,
+    virtual Status runIndexFilterCommand(OperationContext* opCtx,
                                          const std::string& ns,
                                          BSONObj& cmdObj,
                                          BSONObjBuilder* bob);
@@ -176,7 +176,7 @@ public:
      * Sets index filter for a query shape.
      * Removes entry for query shape from plan cache.
      */
-    static Status set(OperationContext* txn,
+    static Status set(OperationContext* opCtx,
                       QuerySettings* querySettings,
                       PlanCache* planCache,
                       const std::string& ns,
diff --git a/src/mongo/db/commands/index_filter_commands_test.cpp b/src/mongo/db/commands/index_filter_commands_test.cpp
index 0da61155048..218a93be606 100644
--- a/src/mongo/db/commands/index_filter_commands_test.cpp
+++ b/src/mongo/db/commands/index_filter_commands_test.cpp
@@ -119,7 +119,7 @@ PlanRankingDecision* createDecision(size_t numPlans) {
 /**
  * Injects an entry into plan cache for query shape.
  */
-void addQueryShapeToPlanCache(OperationContext* txn,
+void addQueryShapeToPlanCache(OperationContext* opCtx,
                               PlanCache* planCache,
                               const char* queryStr,
                               const char* sortStr,
@@ -132,7 +132,7 @@ void addQueryShapeToPlanCache(OperationContext* txn,
     qr->setProj(fromjson(projectionStr));
     qr->setCollation(fromjson(collationStr));
     auto statusWithCQ =
-        CanonicalQuery::canonicalize(txn, std::move(qr), ExtensionsCallbackDisallowExtensions());
+        CanonicalQuery::canonicalize(opCtx, std::move(qr), ExtensionsCallbackDisallowExtensions());
     ASSERT_OK(statusWithCQ.getStatus());
     std::unique_ptr<CanonicalQuery> cq = std::move(statusWithCQ.getValue());
 
@@ -153,7 +153,7 @@ bool planCacheContains(const PlanCache& planCache,
                        const char* projectionStr,
                        const char* collationStr) {
     QueryTestServiceContext serviceContext;
-    auto txn = serviceContext.makeOperationContext();
+    auto opCtx = serviceContext.makeOperationContext();
 
     // Create canonical query.
     auto qr = stdx::make_unique<QueryRequest>(nss);
@@ -162,7 +162,7 @@ bool planCacheContains(const PlanCache& planCache,
     qr->setProj(fromjson(projectionStr));
     qr->setCollation(fromjson(collationStr));
     auto statusWithInputQuery = CanonicalQuery::canonicalize(
-        txn.get(), std::move(qr), ExtensionsCallbackDisallowExtensions());
+        opCtx.get(), std::move(qr), ExtensionsCallbackDisallowExtensions());
     ASSERT_OK(statusWithInputQuery.getStatus());
     unique_ptr<CanonicalQuery> inputQuery = std::move(statusWithInputQuery.getValue());
 
@@ -183,7 +183,7 @@ bool planCacheContains(const PlanCache& planCache,
         qr->setProj(entry->projection);
         qr->setCollation(entry->collation);
         auto statusWithCurrentQuery = CanonicalQuery::canonicalize(
-            txn.get(), std::move(qr), ExtensionsCallbackDisallowExtensions());
+            opCtx.get(), std::move(qr), ExtensionsCallbackDisallowExtensions());
         ASSERT_OK(statusWithCurrentQuery.getStatus());
         unique_ptr<CanonicalQuery> currentQuery = std::move(statusWithCurrentQuery.getValue());
 
@@ -213,34 +213,34 @@ TEST(IndexFilterCommandsTest, ListFiltersEmpty) {
 TEST(IndexFilterCommandsTest, ClearFiltersInvalidParameter) {
     QuerySettings empty;
     PlanCache planCache;
-    OperationContextNoop txn;
+    OperationContextNoop opCtx;
 
     // If present, query has to be an object.
     ASSERT_NOT_OK(
-        ClearFilters::clear(&txn, &empty, &planCache, nss.ns(), fromjson("{query: 1234}")));
+        ClearFilters::clear(&opCtx, &empty, &planCache, nss.ns(), fromjson("{query: 1234}")));
     // If present, sort must be an object.
     ASSERT_NOT_OK(ClearFilters::clear(
-        &txn, &empty, &planCache, nss.ns(), fromjson("{query: {a: 1}, sort: 1234}")));
+        &opCtx, &empty, &planCache, nss.ns(), fromjson("{query: {a: 1}, sort: 1234}")));
     // If present, projection must be an object.
     ASSERT_NOT_OK(ClearFilters::clear(
-        &txn, &empty, &planCache, nss.ns(), fromjson("{query: {a: 1}, projection: 1234}")));
+        &opCtx, &empty, &planCache, nss.ns(), fromjson("{query: {a: 1}, projection: 1234}")));
     // Query must pass canonicalization.
     ASSERT_NOT_OK(ClearFilters::clear(
-        &txn, &empty, &planCache, nss.ns(), fromjson("{query: {a: {$no_such_op: 1}}}")));
+        &opCtx, &empty, &planCache, nss.ns(), fromjson("{query: {a: {$no_such_op: 1}}}")));
     // Sort present without query is an error.
     ASSERT_NOT_OK(
-        ClearFilters::clear(&txn, &empty, &planCache, nss.ns(), fromjson("{sort: {a: 1}}")));
+        ClearFilters::clear(&opCtx, &empty, &planCache, nss.ns(), fromjson("{sort: {a: 1}}")));
     // Projection present without query is an error.
     ASSERT_NOT_OK(ClearFilters::clear(
-        &txn, &empty, &planCache, nss.ns(), fromjson("{projection: {_id: 0, a: 1}}")));
+        &opCtx, &empty, &planCache, nss.ns(), fromjson("{projection: {_id: 0, a: 1}}")));
 }
 
 TEST(IndexFilterCommandsTest, ClearNonexistentHint) {
     QuerySettings querySettings;
     PlanCache planCache;
-    OperationContextNoop txn;
+    OperationContextNoop opCtx;
 
-    ASSERT_OK(SetFilter::set(&txn,
+    ASSERT_OK(SetFilter::set(&opCtx,
                              &querySettings,
                              &planCache,
                              nss.ns(),
@@ -251,7 +251,7 @@ TEST(IndexFilterCommandsTest, ClearNonexistentHint) {
     // Clear nonexistent hint.
     // Command should succeed and cache should remain unchanged.
     ASSERT_OK(ClearFilters::clear(
-        &txn, &querySettings, &planCache, nss.ns(), fromjson("{query: {b: 1}}")));
+        &opCtx, &querySettings, &planCache, nss.ns(), fromjson("{query: {b: 1}}")));
     filters = getFilters(querySettings);
     ASSERT_EQUALS(filters.size(), 1U);
 }
@@ -263,53 +263,57 @@ TEST(IndexFilterCommandsTest, ClearNonexistentHint) {
 TEST(IndexFilterCommandsTest, SetFilterInvalidParameter) {
     QuerySettings empty;
     PlanCache planCache;
-    OperationContextNoop txn;
+    OperationContextNoop opCtx;
 
-    ASSERT_NOT_OK(SetFilter::set(&txn, &empty, &planCache, nss.ns(), fromjson("{}")));
+    ASSERT_NOT_OK(SetFilter::set(&opCtx, &empty, &planCache, nss.ns(), fromjson("{}")));
     // Missing required query field.
     ASSERT_NOT_OK(
-        SetFilter::set(&txn, &empty, &planCache, nss.ns(), fromjson("{indexes: [{a: 1}]}")));
+        SetFilter::set(&opCtx, &empty, &planCache, nss.ns(), fromjson("{indexes: [{a: 1}]}")));
     // Missing required indexes field.
-    ASSERT_NOT_OK(SetFilter::set(&txn, &empty, &planCache, nss.ns(), fromjson("{query: {a: 1}}")));
+    ASSERT_NOT_OK(
+        SetFilter::set(&opCtx, &empty, &planCache, nss.ns(), fromjson("{query: {a: 1}}")));
     // Query has to be an object.
-    ASSERT_NOT_OK(SetFilter::set(
-        &txn, &empty, &planCache, nss.ns(), fromjson("{query: 1234, indexes: [{a: 1}, {b: 1}]}")));
+    ASSERT_NOT_OK(SetFilter::set(&opCtx,
+                                 &empty,
+                                 &planCache,
+                                 nss.ns(),
+                                 fromjson("{query: 1234, indexes: [{a: 1}, {b: 1}]}")));
     // Indexes field has to be an array.
     ASSERT_NOT_OK(SetFilter::set(
-        &txn, &empty, &planCache, nss.ns(), fromjson("{query: {a: 1}, indexes: 1234}")));
+        &opCtx, &empty, &planCache, nss.ns(), fromjson("{query: {a: 1}, indexes: 1234}")));
     // Array indexes field cannot empty.
     ASSERT_NOT_OK(SetFilter::set(
-        &txn, &empty, &planCache, nss.ns(), fromjson("{query: {a: 1}, indexes: []}")));
+        &opCtx, &empty, &planCache, nss.ns(), fromjson("{query: {a: 1}, indexes: []}")));
     // Elements in indexes have to be objects.
     ASSERT_NOT_OK(SetFilter::set(
-        &txn, &empty, &planCache, nss.ns(), fromjson("{query: {a: 1}, indexes: [{a: 1}, 99]}")));
+        &opCtx, &empty, &planCache, nss.ns(), fromjson("{query: {a: 1}, indexes: [{a: 1}, 99]}")));
     // Objects in indexes cannot be empty.
     ASSERT_NOT_OK(SetFilter::set(
-        &txn, &empty, &planCache, nss.ns(), fromjson("{query: {a: 1}, indexes: [{a: 1}, {}]}")));
+        &opCtx, &empty, &planCache, nss.ns(), fromjson("{query: {a: 1}, indexes: [{a: 1}, {}]}")));
     // If present, sort must be an object.
     ASSERT_NOT_OK(
-        SetFilter::set(&txn,
+        SetFilter::set(&opCtx,
                        &empty,
                        &planCache,
                        nss.ns(),
                        fromjson("{query: {a: 1}, sort: 1234, indexes: [{a: 1}, {b: 1}]}")));
     // If present, projection must be an object.
     ASSERT_NOT_OK(
-        SetFilter::set(&txn,
+        SetFilter::set(&opCtx,
                        &empty,
                        &planCache,
                        nss.ns(),
                        fromjson("{query: {a: 1}, projection: 1234, indexes: [{a: 1}, {b: 1}]}")));
     // If present, collation must be an object.
     ASSERT_NOT_OK(
-        SetFilter::set(&txn,
+        SetFilter::set(&opCtx,
                        &empty,
                        &planCache,
                        nss.ns(),
                        fromjson("{query: {a: 1}, collation: 1234, indexes: [{a: 1}, {b: 1}]}")));
     // Query must pass canonicalization.
     ASSERT_NOT_OK(
-        SetFilter::set(&txn,
+        SetFilter::set(&opCtx,
                        &empty,
                        &planCache,
                        nss.ns(),
@@ -320,10 +324,10 @@ TEST(IndexFilterCommandsTest, SetAndClearFilters) {
     QuerySettings querySettings;
     PlanCache planCache;
     QueryTestServiceContext serviceContext;
-    auto txn = serviceContext.makeOperationContext();
+    auto opCtx = serviceContext.makeOperationContext();
 
     // Inject query shape into plan cache.
-    addQueryShapeToPlanCache(txn.get(),
+    addQueryShapeToPlanCache(opCtx.get(),
                              &planCache,
                              "{a: 1, b: 1}",
                              "{a: -1}",
@@ -332,7 +336,7 @@ TEST(IndexFilterCommandsTest, SetAndClearFilters) {
     ASSERT_TRUE(planCacheContains(
         planCache, "{a: 1, b: 1}", "{a: -1}", "{_id: 0, a: 1}", "{locale: 'mock_reverse_string'}"));
 
-    ASSERT_OK(SetFilter::set(txn.get(),
+    ASSERT_OK(SetFilter::set(opCtx.get(),
                              &querySettings,
                              &planCache,
                              nss.ns(),
@@ -355,7 +359,7 @@ TEST(IndexFilterCommandsTest, SetAndClearFilters) {
 
     // Replacing the hint for the same query shape ({a: 1, b: 1} and {b: 2, a: 3}
     // share same shape) should not change the query settings size.
-    ASSERT_OK(SetFilter::set(txn.get(),
+    ASSERT_OK(SetFilter::set(opCtx.get(),
                              &querySettings,
                              &planCache,
                              nss.ns(),
@@ -371,7 +375,7 @@ TEST(IndexFilterCommandsTest, SetAndClearFilters) {
     ASSERT_BSONOBJ_EQ(filterArray[0].Obj(), fromjson("{a: 1, b: 1}"));
 
     // Add hint for different query shape.
-    ASSERT_OK(SetFilter::set(txn.get(),
+    ASSERT_OK(SetFilter::set(opCtx.get(),
                              &querySettings,
                              &planCache,
                              nss.ns(),
@@ -380,7 +384,7 @@ TEST(IndexFilterCommandsTest, SetAndClearFilters) {
     ASSERT_EQUALS(filters.size(), 2U);
 
     // Add hint for 3rd query shape. This is to prepare for ClearHint tests.
-    ASSERT_OK(SetFilter::set(txn.get(),
+    ASSERT_OK(SetFilter::set(opCtx.get(),
                              &querySettings,
                              &planCache,
                              nss.ns(),
@@ -389,12 +393,12 @@ TEST(IndexFilterCommandsTest, SetAndClearFilters) {
     ASSERT_EQUALS(filters.size(), 3U);
 
     // Add 2 entries to plan cache and check plan cache after clearing one/all filters.
-    addQueryShapeToPlanCache(txn.get(), &planCache, "{a: 1}", "{}", "{}", "{}");
-    addQueryShapeToPlanCache(txn.get(), &planCache, "{b: 1}", "{}", "{}", "{}");
+    addQueryShapeToPlanCache(opCtx.get(), &planCache, "{a: 1}", "{}", "{}", "{}");
+    addQueryShapeToPlanCache(opCtx.get(), &planCache, "{b: 1}", "{}", "{}", "{}");
 
     // Clear single hint.
     ASSERT_OK(ClearFilters::clear(
-        txn.get(), &querySettings, &planCache, nss.ns(), fromjson("{query: {a: 1}}")));
+        opCtx.get(), &querySettings, &planCache, nss.ns(), fromjson("{query: {a: 1}}")));
     filters = getFilters(querySettings);
     ASSERT_EQUALS(filters.size(), 2U);
 
@@ -403,7 +407,8 @@ TEST(IndexFilterCommandsTest, SetAndClearFilters) {
     ASSERT_TRUE(planCacheContains(planCache, "{b: 1}", "{}", "{}", "{}"));
 
     // Clear all filters
-    ASSERT_OK(ClearFilters::clear(txn.get(), &querySettings, &planCache, nss.ns(), fromjson("{}")));
+    ASSERT_OK(
+        ClearFilters::clear(opCtx.get(), &querySettings, &planCache, nss.ns(), fromjson("{}")));
     filters = getFilters(querySettings);
     ASSERT_TRUE(filters.empty());
 
@@ -413,7 +418,7 @@ TEST(IndexFilterCommandsTest, SetAndClearFilters) {
 
 TEST(IndexFilterCommandsTest, SetAndClearFiltersCollation) {
     QueryTestServiceContext serviceContext;
-    auto txn = serviceContext.makeOperationContext();
+    auto opCtx = serviceContext.makeOperationContext();
     QuerySettings querySettings;
 
     // Create a plan cache. Add an index so that indexability is included in the plan cache keys.
@@ -423,13 +428,13 @@ TEST(IndexFilterCommandsTest, SetAndClearFiltersCollation) {
 
     // Inject query shapes with and without collation into plan cache.
     addQueryShapeToPlanCache(
-        txn.get(), &planCache, "{a: 'foo'}", "{}", "{}", "{locale: 'mock_reverse_string'}");
-    addQueryShapeToPlanCache(txn.get(), &planCache, "{a: 'foo'}", "{}", "{}", "{}");
+        opCtx.get(), &planCache, "{a: 'foo'}", "{}", "{}", "{locale: 'mock_reverse_string'}");
+    addQueryShapeToPlanCache(opCtx.get(), &planCache, "{a: 'foo'}", "{}", "{}", "{}");
     ASSERT_TRUE(
         planCacheContains(planCache, "{a: 'foo'}", "{}", "{}", "{locale: 'mock_reverse_string'}"));
     ASSERT_TRUE(planCacheContains(planCache, "{a: 'foo'}", "{}", "{}", "{}"));
 
-    ASSERT_OK(SetFilter::set(txn.get(),
+    ASSERT_OK(SetFilter::set(opCtx.get(),
                              &querySettings,
                              &planCache,
                              nss.ns(),
@@ -450,7 +455,7 @@ TEST(IndexFilterCommandsTest, SetAndClearFiltersCollation) {
     ASSERT_TRUE(planCacheContains(planCache, "{a: 'foo'}", "{}", "{}", "{}"));
 
     // Add filter for query shape without collation.
-    ASSERT_OK(SetFilter::set(txn.get(),
+    ASSERT_OK(SetFilter::set(opCtx.get(),
                              &querySettings,
                              &planCache,
                              nss.ns(),
@@ -460,12 +465,12 @@ TEST(IndexFilterCommandsTest, SetAndClearFiltersCollation) {
 
     // Add plan cache entries for both queries.
     addQueryShapeToPlanCache(
-        txn.get(), &planCache, "{a: 'foo'}", "{}", "{}", "{locale: 'mock_reverse_string'}");
-    addQueryShapeToPlanCache(txn.get(), &planCache, "{a: 'foo'}", "{}", "{}", "{}");
+        opCtx.get(), &planCache, "{a: 'foo'}", "{}", "{}", "{locale: 'mock_reverse_string'}");
+    addQueryShapeToPlanCache(opCtx.get(), &planCache, "{a: 'foo'}", "{}", "{}", "{}");
 
     // Clear filter for query with collation.
     ASSERT_OK(ClearFilters::clear(
-        txn.get(),
+        opCtx.get(),
         &querySettings,
         &planCache,
         nss.ns(),
@@ -490,7 +495,7 @@ TEST(IndexFilterCommandsTest, SetFilterAcceptsIndexNames) {
         fromjson("{a: 1}"), false, false, false, "a_1:rev", nullptr, BSONObj());
     collatedIndex.collator = &reverseCollator;
     QueryTestServiceContext serviceContext;
-    auto txn = serviceContext.makeOperationContext();
+    auto opCtx = serviceContext.makeOperationContext();
     QuerySettings querySettings;
 
     PlanCache planCache;
@@ -498,10 +503,10 @@ TEST(IndexFilterCommandsTest, SetFilterAcceptsIndexNames) {
         {IndexEntry(fromjson("{a: 1}"), false, false, false, "a_1", nullptr, BSONObj()),
          collatedIndex});
 
-    addQueryShapeToPlanCache(txn.get(), &planCache, "{a: 2}", "{}", "{}", "{}");
+    addQueryShapeToPlanCache(opCtx.get(), &planCache, "{a: 2}", "{}", "{}", "{}");
     ASSERT_TRUE(planCacheContains(planCache, "{a: 2}", "{}", "{}", "{}"));
 
-    ASSERT_OK(SetFilter::set(txn.get(),
+    ASSERT_OK(SetFilter::set(opCtx.get(),
                              &querySettings,
                              &planCache,
                              nss.ns(),
diff --git a/src/mongo/db/commands/isself.cpp b/src/mongo/db/commands/isself.cpp
index 0db7ba01440..6e8c1509b5f 100644
--- a/src/mongo/db/commands/isself.cpp
+++ b/src/mongo/db/commands/isself.cpp
@@ -54,7 +54,7 @@ public:
     virtual void addRequiredPrivileges(const std::string& dbname,
                                        const BSONObj& cmdObj,
                                        std::vector<Privilege>* out) {}  // No auth required
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int,
diff --git a/src/mongo/db/commands/kill_op.cpp b/src/mongo/db/commands/kill_op.cpp
index f96f3692ecd..1d16113ca93 100644
--- a/src/mongo/db/commands/kill_op.cpp
+++ b/src/mongo/db/commands/kill_op.cpp
@@ -128,7 +128,7 @@ public:
         return Status(ErrorCodes::Unauthorized, "Unauthorized");
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const std::string& db,
              BSONObj& cmdObj,
              int options,
@@ -138,12 +138,12 @@ public:
 
         log() << "going to kill op: " << opId;
         result.append("info", "attempting to kill op");
-        auto swLkAndOp = _findOp(txn->getClient(), opId);
+        auto swLkAndOp = _findOp(opCtx->getClient(), opId);
         if (swLkAndOp.isOK()) {
             stdx::unique_lock<Client> lk;
             OperationContext* opCtx;
             std::tie(lk, opCtx) = std::move(swLkAndOp.getValue());
-            txn->getServiceContext()->killOperation(opCtx);
+            opCtx->getServiceContext()->killOperation(opCtx);
         }
 
         return true;
diff --git a/src/mongo/db/commands/killcursors_cmd.cpp b/src/mongo/db/commands/killcursors_cmd.cpp
index 5831d3b2cc0..e51e4d65f8a 100644
--- a/src/mongo/db/commands/killcursors_cmd.cpp
+++ b/src/mongo/db/commands/killcursors_cmd.cpp
@@ -45,7 +45,9 @@ public:
     KillCursorsCmd() = default;
 
 private:
-    Status _killCursor(OperationContext* txn, const NamespaceString& nss, CursorId cursorId) final {
+    Status _killCursor(OperationContext* opCtx,
+                       const NamespaceString& nss,
+                       CursorId cursorId) final {
         std::unique_ptr<AutoGetCollectionOrViewForRead> ctx;
 
         CursorManager* cursorManager;
@@ -55,22 +57,22 @@ private:
             // data within a collection.
             cursorManager = CursorManager::getGlobalCursorManager();
         } else {
-            ctx = stdx::make_unique<AutoGetCollectionOrViewForRead>(txn, nss);
+            ctx = stdx::make_unique<AutoGetCollectionOrViewForRead>(opCtx, nss);
             Collection* collection = ctx->getCollection();
             ViewDefinition* view = ctx->getView();
             if (view) {
                 Database* db = ctx->getDb();
-                auto resolved = db->getViewCatalog()->resolveView(txn, nss);
+                auto resolved = db->getViewCatalog()->resolveView(opCtx, nss);
                 if (!resolved.isOK()) {
                     return resolved.getStatus();
                 }
                 ctx->releaseLocksForView();
-                Status status = _killCursor(txn, resolved.getValue().getNamespace(), cursorId);
+                Status status = _killCursor(opCtx, resolved.getValue().getNamespace(), cursorId);
                 {
                     // Set the namespace of the curop back to the view namespace so ctx records
                     // stats on this view namespace on destruction.
-                    stdx::lock_guard<Client> lk(*txn->getClient());
-                    CurOp::get(txn)->setNS_inlock(nss.ns());
+                    stdx::lock_guard<Client> lk(*opCtx->getClient());
+                    CurOp::get(opCtx)->setNS_inlock(nss.ns());
                 }
                 return status;
             }
@@ -82,7 +84,7 @@ private:
         }
         invariant(cursorManager);
 
-        return cursorManager->eraseCursor(txn, cursorId, true /*shouldAudit*/);
+        return cursorManager->eraseCursor(opCtx, cursorId, true /*shouldAudit*/);
     }
 } killCursorsCmd;
 
diff --git a/src/mongo/db/commands/killcursors_common.cpp b/src/mongo/db/commands/killcursors_common.cpp
index 194882feee2..570c1e1df0e 100644
--- a/src/mongo/db/commands/killcursors_common.cpp
+++ b/src/mongo/db/commands/killcursors_common.cpp
@@ -63,7 +63,7 @@ Status KillCursorsCmdBase::checkAuthForCommand(Client* client,
     return Status::OK();
 }
 
-bool KillCursorsCmdBase::run(OperationContext* txn,
+bool KillCursorsCmdBase::run(OperationContext* opCtx,
                              const std::string& dbname,
                              BSONObj& cmdObj,
                              int options,
@@ -81,7 +81,7 @@ bool KillCursorsCmdBase::run(OperationContext* txn,
     std::vector<CursorId> cursorsUnknown;
 
     for (CursorId id : killCursorsRequest.cursorIds) {
-        Status status = _killCursor(txn, killCursorsRequest.nss, id);
+        Status status = _killCursor(opCtx, killCursorsRequest.nss, id);
         if (status.isOK()) {
             cursorsKilled.push_back(id);
         } else if (status.code() == ErrorCodes::CursorNotFound) {
@@ -91,7 +91,7 @@ bool KillCursorsCmdBase::run(OperationContext* txn,
         }
 
         audit::logKillCursorsAuthzCheck(
-            txn->getClient(), killCursorsRequest.nss, id, status.code());
+            opCtx->getClient(), killCursorsRequest.nss, id, status.code());
     }
 
     KillCursorsResponse killCursorsResponse(
diff --git a/src/mongo/db/commands/killcursors_common.h b/src/mongo/db/commands/killcursors_common.h
index 3f66f845ef0..c5b6e9db31d 100644
--- a/src/mongo/db/commands/killcursors_common.h
+++ b/src/mongo/db/commands/killcursors_common.h
@@ -70,7 +70,7 @@ public:
                                const std::string& dbname,
                                const BSONObj& cmdObj) final;
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const std::string& dbname,
              BSONObj& cmdObj,
              int options,
@@ -79,12 +79,12 @@ public:
 
 private:
     /**
-     * Kill the cursor with id 'cursorId' in namespace 'nss'. Use 'txn' if necessary.
+     * Kill the cursor with id 'cursorId' in namespace 'nss'. Use 'opCtx' if necessary.
      *
      * Returns Status::OK() if the cursor was killed, or ErrorCodes::CursorNotFound if there is no
      * such cursor, or ErrorCodes::OperationFailed if the cursor cannot be killed.
      */
-    virtual Status _killCursor(OperationContext* txn,
+    virtual Status _killCursor(OperationContext* opCtx,
                                const NamespaceString& nss,
                                CursorId cursorId) = 0;
 };
diff --git a/src/mongo/db/commands/list_collections.cpp b/src/mongo/db/commands/list_collections.cpp
index 0309abe8c7c..68a6337f548 100644
--- a/src/mongo/db/commands/list_collections.cpp
+++ b/src/mongo/db/commands/list_collections.cpp
@@ -111,7 +111,7 @@ boost::optional<vector<StringData>> _getExactNameMatches(const MatchExpression*
  *
  * Does not add any information about the system.namespaces collection, or non-existent collections.
  */
-void _addWorkingSetMember(OperationContext* txn,
+void _addWorkingSetMember(OperationContext* opCtx,
                           const BSONObj& maybe,
                           const MatchExpression* matcher,
                           WorkingSet* ws,
@@ -147,7 +147,7 @@ BSONObj buildViewBson(const ViewDefinition& view) {
     return b.obj();
 }
 
-BSONObj buildCollectionBson(OperationContext* txn, const Collection* collection) {
+BSONObj buildCollectionBson(OperationContext* opCtx, const Collection* collection) {
 
     if (!collection) {
         return {};
@@ -162,13 +162,13 @@ BSONObj buildCollectionBson(OperationContext* txn, const Collection* collection)
     b.append("name", collectionName);
     b.append("type", "collection");
 
-    CollectionOptions options = collection->getCatalogEntry()->getCollectionOptions(txn);
+    CollectionOptions options = collection->getCatalogEntry()->getCollectionOptions(opCtx);
     b.append("options", options.toBSON());
 
     BSONObj info = BSON("readOnly" << storageGlobalParams.readOnly);
     b.append("info", info);
 
-    auto idIndex = collection->getIndexCatalog()->findIdIndex(txn);
+    auto idIndex = collection->getIndexCatalog()->findIdIndex(opCtx);
     if (idIndex) {
         b.append("idIndex", idIndex->infoObj());
     }
@@ -216,7 +216,7 @@ public:
 
     CmdListCollections() : Command("listCollections") {}
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& jsobj,
              int,
@@ -247,29 +247,29 @@ public:
             return appendCommandStatus(result, parseCursorStatus);
         }
 
-        ScopedTransaction scopedXact(txn, MODE_IS);
-        AutoGetDb autoDb(txn, dbname, MODE_S);
+        ScopedTransaction scopedXact(opCtx, MODE_IS);
+        AutoGetDb autoDb(opCtx, dbname, MODE_S);
 
         Database* db = autoDb.getDb();
 
         auto ws = make_unique<WorkingSet>();
-        auto root = make_unique<QueuedDataStage>(txn, ws.get());
+        auto root = make_unique<QueuedDataStage>(opCtx, ws.get());
 
         if (db) {
             if (auto collNames = _getExactNameMatches(matcher.get())) {
                 for (auto&& collName : *collNames) {
                     auto nss = NamespaceString(db->name(), collName);
                     Collection* collection = db->getCollection(nss);
-                    BSONObj collBson = buildCollectionBson(txn, collection);
+                    BSONObj collBson = buildCollectionBson(opCtx, collection);
                     if (!collBson.isEmpty()) {
-                        _addWorkingSetMember(txn, collBson, matcher.get(), ws.get(), root.get());
+                        _addWorkingSetMember(opCtx, collBson, matcher.get(), ws.get(), root.get());
                     }
                 }
             } else {
                 for (auto&& collection : *db) {
-                    BSONObj collBson = buildCollectionBson(txn, collection);
+                    BSONObj collBson = buildCollectionBson(opCtx, collection);
                     if (!collBson.isEmpty()) {
-                        _addWorkingSetMember(txn, collBson, matcher.get(), ws.get(), root.get());
+                        _addWorkingSetMember(opCtx, collBson, matcher.get(), ws.get(), root.get());
                     }
                 }
             }
@@ -279,10 +279,10 @@ public:
                 SimpleBSONObjComparator::kInstance.evaluate(
                     filterElt.Obj() == ListCollectionsFilter::makeTypeCollectionFilter());
             if (!skipViews) {
-                db->getViewCatalog()->iterate(txn, [&](const ViewDefinition& view) {
+                db->getViewCatalog()->iterate(opCtx, [&](const ViewDefinition& view) {
                     BSONObj viewBson = buildViewBson(view);
                     if (!viewBson.isEmpty()) {
-                        _addWorkingSetMember(txn, viewBson, matcher.get(), ws.get(), root.get());
+                        _addWorkingSetMember(opCtx, viewBson, matcher.get(), ws.get(), root.get());
                     }
                 });
             }
@@ -291,7 +291,7 @@ public:
         const NamespaceString cursorNss = NamespaceString::makeListCollectionsNSS(dbname);
 
         auto statusWithPlanExecutor = PlanExecutor::make(
-            txn, std::move(ws), std::move(root), cursorNss.ns(), PlanExecutor::YIELD_MANUAL);
+            opCtx, std::move(ws), std::move(root), cursorNss.ns(), PlanExecutor::YIELD_MANUAL);
         if (!statusWithPlanExecutor.isOK()) {
             return appendCommandStatus(result, statusWithPlanExecutor.getStatus());
         }
@@ -323,7 +323,7 @@ public:
             auto pinnedCursor = CursorManager::getGlobalCursorManager()->registerCursor(
                 {exec.release(),
                  cursorNss.ns(),
-                 txn->recoveryUnit()->isReadingFromMajorityCommittedSnapshot()});
+                 opCtx->recoveryUnit()->isReadingFromMajorityCommittedSnapshot()});
             cursorId = pinnedCursor.getCursor()->cursorid();
         }
 
diff --git a/src/mongo/db/commands/list_databases.cpp b/src/mongo/db/commands/list_databases.cpp
index 08de6f6cd6f..ccc2f82cc49 100644
--- a/src/mongo/db/commands/list_databases.cpp
+++ b/src/mongo/db/commands/list_databases.cpp
@@ -83,7 +83,7 @@ public:
 
     CmdListDatabases() : Command("listDatabases", true) {}
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& jsobj,
              int,
@@ -114,8 +114,8 @@ public:
         vector<string> dbNames;
         StorageEngine* storageEngine = getGlobalServiceContext()->getGlobalStorageEngine();
         {
-            ScopedTransaction transaction(txn, MODE_IS);
-            Lock::GlobalLock lk(txn->lockState(), MODE_IS, UINT_MAX);
+            ScopedTransaction transaction(opCtx, MODE_IS);
+            Lock::GlobalLock lk(opCtx->lockState(), MODE_IS, UINT_MAX);
             storageEngine->listDatabases(&dbNames);
         }
 
@@ -135,17 +135,17 @@ public:
                 if (filterNameOnly && !filter->matchesBSON(b.asTempObj()))
                     continue;
 
-                ScopedTransaction transaction(txn, MODE_IS);
-                Lock::DBLock dbLock(txn->lockState(), dbname, MODE_IS);
+                ScopedTransaction transaction(opCtx, MODE_IS);
+                Lock::DBLock dbLock(opCtx->lockState(), dbname, MODE_IS);
 
-                Database* db = dbHolder().get(txn, dbname);
+                Database* db = dbHolder().get(opCtx, dbname);
                 if (!db)
                     continue;
 
                 const DatabaseCatalogEntry* entry = db->getDatabaseCatalogEntry();
                 invariant(entry);
 
-                size = entry->sizeOnDisk(txn);
+                size = entry->sizeOnDisk(opCtx);
                 b.append("sizeOnDisk", static_cast<double>(size));
 
                 b.appendBool("empty", entry->isEmpty());
diff --git a/src/mongo/db/commands/list_indexes.cpp b/src/mongo/db/commands/list_indexes.cpp
index 59528d8bf11..940edb13eda 100644
--- a/src/mongo/db/commands/list_indexes.cpp
+++ b/src/mongo/db/commands/list_indexes.cpp
@@ -116,7 +116,7 @@ public:
 
     CmdListIndexes() : Command("listIndexes") {}
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int,
@@ -132,7 +132,7 @@ public:
             return appendCommandStatus(result, parseCursorStatus);
         }
 
-        AutoGetCollectionForRead autoColl(txn, ns);
+        AutoGetCollectionForRead autoColl(opCtx, ns);
         if (!autoColl.getDb()) {
             return appendCommandStatus(result,
                                        Status(ErrorCodes::NamespaceNotFound, "no database"));
@@ -150,19 +150,19 @@ public:
         vector<string> indexNames;
         MONGO_WRITE_CONFLICT_RETRY_LOOP_BEGIN {
             indexNames.clear();
-            cce->getAllIndexes(txn, &indexNames);
+            cce->getAllIndexes(opCtx, &indexNames);
         }
-        MONGO_WRITE_CONFLICT_RETRY_LOOP_END(txn, "listIndexes", ns.ns());
+        MONGO_WRITE_CONFLICT_RETRY_LOOP_END(opCtx, "listIndexes", ns.ns());
 
         auto ws = make_unique<WorkingSet>();
-        auto root = make_unique<QueuedDataStage>(txn, ws.get());
+        auto root = make_unique<QueuedDataStage>(opCtx, ws.get());
 
         for (size_t i = 0; i < indexNames.size(); i++) {
             BSONObj indexSpec;
             MONGO_WRITE_CONFLICT_RETRY_LOOP_BEGIN {
-                indexSpec = cce->getIndexSpec(txn, indexNames[i]);
+                indexSpec = cce->getIndexSpec(opCtx, indexNames[i]);
             }
-            MONGO_WRITE_CONFLICT_RETRY_LOOP_END(txn, "listIndexes", ns.ns());
+            MONGO_WRITE_CONFLICT_RETRY_LOOP_END(opCtx, "listIndexes", ns.ns());
 
             if (ns.ns() == FeatureCompatibilityVersion::kCollection &&
                 indexNames[i] == FeatureCompatibilityVersion::k32IncompatibleIndexName) {
@@ -198,7 +198,7 @@ public:
         dassert(ns == cursorNss.getTargetNSForListIndexes());
 
         auto statusWithPlanExecutor = PlanExecutor::make(
-            txn, std::move(ws), std::move(root), cursorNss.ns(), PlanExecutor::YIELD_MANUAL);
+            opCtx, std::move(ws), std::move(root), cursorNss.ns(), PlanExecutor::YIELD_MANUAL);
         if (!statusWithPlanExecutor.isOK()) {
             return appendCommandStatus(result, statusWithPlanExecutor.getStatus());
         }
@@ -230,7 +230,7 @@ public:
             auto pinnedCursor = CursorManager::getGlobalCursorManager()->registerCursor(
                 {exec.release(),
                  cursorNss.ns(),
-                 txn->recoveryUnit()->isReadingFromMajorityCommittedSnapshot()});
+                 opCtx->recoveryUnit()->isReadingFromMajorityCommittedSnapshot()});
             cursorId = pinnedCursor.getCursor()->cursorid();
         }
 
diff --git a/src/mongo/db/commands/lock_info.cpp b/src/mongo/db/commands/lock_info.cpp
index 950533ae333..69dd15a6c0b 100644
--- a/src/mongo/db/commands/lock_info.cpp
+++ b/src/mongo/db/commands/lock_info.cpp
@@ -79,7 +79,7 @@ public:
 
     CmdLockInfo() : Command("lockInfo", true) {}
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& jsobj,
              int,
@@ -87,7 +87,7 @@ public:
              BSONObjBuilder& result) {
         std::map<LockerId, BSONObj> lockToClientMap;
 
-        for (ServiceContext::LockedClientsCursor cursor(txn->getClient()->getServiceContext());
+        for (ServiceContext::LockedClientsCursor cursor(opCtx->getClient()->getServiceContext());
              Client* client = cursor.next();) {
             invariant(client);
 
diff --git a/src/mongo/db/commands/mr.cpp b/src/mongo/db/commands/mr.cpp
index 781c0d1d5af..25e9590a6d9 100644
--- a/src/mongo/db/commands/mr.cpp
+++ b/src/mongo/db/commands/mr.cpp
@@ -372,40 +372,40 @@ Config::Config(const string& _dbname, const BSONObj& cmdObj) {
 void State::dropTempCollections() {
     if (!_config.tempNamespace.isEmpty()) {
         MONGO_WRITE_CONFLICT_RETRY_LOOP_BEGIN {
-            ScopedTransaction scopedXact(_txn, MODE_IX);
-            AutoGetDb autoDb(_txn, _config.tempNamespace.db(), MODE_X);
+            ScopedTransaction scopedXact(_opCtx, MODE_IX);
+            AutoGetDb autoDb(_opCtx, _config.tempNamespace.db(), MODE_X);
             if (auto db = autoDb.getDb()) {
-                WriteUnitOfWork wunit(_txn);
+                WriteUnitOfWork wunit(_opCtx);
                 uassert(ErrorCodes::PrimarySteppedDown,
                         "no longer primary",
                         repl::getGlobalReplicationCoordinator()->canAcceptWritesFor(
-                            _txn, _config.tempNamespace));
-                db->dropCollection(_txn, _config.tempNamespace.ns());
+                            _opCtx, _config.tempNamespace));
+                db->dropCollection(_opCtx, _config.tempNamespace.ns());
                 wunit.commit();
             }
         }
         MONGO_WRITE_CONFLICT_RETRY_LOOP_END(
-            _txn, "M/R dropTempCollections", _config.tempNamespace.ns())
+            _opCtx, "M/R dropTempCollections", _config.tempNamespace.ns())
         // Always forget about temporary namespaces, so we don't cache lots of them
         ShardConnection::forgetNS(_config.tempNamespace.ns());
     }
     if (_useIncremental && !_config.incLong.isEmpty()) {
         // We don't want to log the deletion of incLong as it isn't replicated. While
         // harmless, this would lead to a scary looking warning on the secondaries.
-        bool shouldReplicateWrites = _txn->writesAreReplicated();
-        _txn->setReplicatedWrites(false);
-        ON_BLOCK_EXIT(&OperationContext::setReplicatedWrites, _txn, shouldReplicateWrites);
+        bool shouldReplicateWrites = _opCtx->writesAreReplicated();
+        _opCtx->setReplicatedWrites(false);
+        ON_BLOCK_EXIT(&OperationContext::setReplicatedWrites, _opCtx, shouldReplicateWrites);
 
         MONGO_WRITE_CONFLICT_RETRY_LOOP_BEGIN {
-            ScopedTransaction scopedXact(_txn, MODE_IX);
-            Lock::DBLock lk(_txn->lockState(), _config.incLong.db(), MODE_X);
-            if (Database* db = dbHolder().get(_txn, _config.incLong.ns())) {
-                WriteUnitOfWork wunit(_txn);
-                db->dropCollection(_txn, _config.incLong.ns());
+            ScopedTransaction scopedXact(_opCtx, MODE_IX);
+            Lock::DBLock lk(_opCtx->lockState(), _config.incLong.db(), MODE_X);
+            if (Database* db = dbHolder().get(_opCtx, _config.incLong.ns())) {
+                WriteUnitOfWork wunit(_opCtx);
+                db->dropCollection(_opCtx, _config.incLong.ns());
                 wunit.commit();
             }
         }
-        MONGO_WRITE_CONFLICT_RETRY_LOOP_END(_txn, "M/R dropTempCollections", _config.incLong.ns())
+        MONGO_WRITE_CONFLICT_RETRY_LOOP_END(_opCtx, "M/R dropTempCollections", _config.incLong.ns())
 
         ShardConnection::forgetNS(_config.incLong.ns());
     }
@@ -422,20 +422,20 @@ void State::prepTempCollection() {
     if (_useIncremental) {
         // Create the inc collection and make sure we have index on "0" key.
         // Intentionally not replicating the inc collection to secondaries.
-        bool shouldReplicateWrites = _txn->writesAreReplicated();
-        _txn->setReplicatedWrites(false);
-        ON_BLOCK_EXIT(&OperationContext::setReplicatedWrites, _txn, shouldReplicateWrites);
+        bool shouldReplicateWrites = _opCtx->writesAreReplicated();
+        _opCtx->setReplicatedWrites(false);
+        ON_BLOCK_EXIT(&OperationContext::setReplicatedWrites, _opCtx, shouldReplicateWrites);
 
         MONGO_WRITE_CONFLICT_RETRY_LOOP_BEGIN {
-            OldClientWriteContext incCtx(_txn, _config.incLong.ns());
-            WriteUnitOfWork wuow(_txn);
+            OldClientWriteContext incCtx(_opCtx, _config.incLong.ns());
+            WriteUnitOfWork wuow(_opCtx);
             Collection* incColl = incCtx.getCollection();
             invariant(!incColl);
 
             CollectionOptions options;
             options.setNoIdIndex();
             options.temp = true;
-            incColl = incCtx.db()->createCollection(_txn, _config.incLong.ns(), options);
+            incColl = incCtx.db()->createCollection(_opCtx, _config.incLong.ns(), options);
             invariant(incColl);
 
             // We explicitly create a v=2 index on the "0" field so that it is always possible for a
@@ -448,7 +448,7 @@ void State::prepTempCollection() {
                            << "v"
                            << static_cast<int>(IndexVersion::kV2));
             Status status = incColl->getIndexCatalog()
-                                ->createIndexOnEmptyCollection(_txn, indexSpec)
+                                ->createIndexOnEmptyCollection(_opCtx, indexSpec)
                                 .getStatus();
             if (!status.isOK()) {
                 uasserted(17305,
@@ -459,7 +459,7 @@ void State::prepTempCollection() {
             }
             wuow.commit();
         }
-        MONGO_WRITE_CONFLICT_RETRY_LOOP_END(_txn, "M/R prepTempCollection", _config.incLong.ns());
+        MONGO_WRITE_CONFLICT_RETRY_LOOP_END(_opCtx, "M/R prepTempCollection", _config.incLong.ns());
     }
 
     CollectionOptions finalOptions;
@@ -467,13 +467,13 @@ void State::prepTempCollection() {
 
     {
         // copy indexes and collection options into temporary storage
-        OldClientWriteContext finalCtx(_txn, _config.outputOptions.finalNamespace.ns());
+        OldClientWriteContext finalCtx(_opCtx, _config.outputOptions.finalNamespace.ns());
         Collection* const finalColl = finalCtx.getCollection();
         if (finalColl) {
-            finalOptions = finalColl->getCatalogEntry()->getCollectionOptions(_txn);
+            finalOptions = finalColl->getCatalogEntry()->getCollectionOptions(_opCtx);
 
             IndexCatalog::IndexIterator ii =
-                finalColl->getIndexCatalog()->getIndexIterator(_txn, true);
+                finalColl->getIndexCatalog()->getIndexIterator(_opCtx, true);
             // Iterate over finalColl's indexes.
             while (ii.more()) {
                 IndexDescriptor* currIndex = ii.next();
@@ -495,23 +495,23 @@ void State::prepTempCollection() {
 
     MONGO_WRITE_CONFLICT_RETRY_LOOP_BEGIN {
         // create temp collection and insert the indexes from temporary storage
-        OldClientWriteContext tempCtx(_txn, _config.tempNamespace.ns());
-        WriteUnitOfWork wuow(_txn);
+        OldClientWriteContext tempCtx(_opCtx, _config.tempNamespace.ns());
+        WriteUnitOfWork wuow(_opCtx);
         uassert(ErrorCodes::PrimarySteppedDown,
                 "no longer primary",
-                repl::getGlobalReplicationCoordinator()->canAcceptWritesFor(_txn,
+                repl::getGlobalReplicationCoordinator()->canAcceptWritesFor(_opCtx,
                                                                             _config.tempNamespace));
         Collection* tempColl = tempCtx.getCollection();
         invariant(!tempColl);
 
         CollectionOptions options = finalOptions;
         options.temp = true;
-        tempColl = tempCtx.db()->createCollection(_txn, _config.tempNamespace.ns(), options);
+        tempColl = tempCtx.db()->createCollection(_opCtx, _config.tempNamespace.ns(), options);
 
         for (vector<BSONObj>::iterator it = indexesToInsert.begin(); it != indexesToInsert.end();
              ++it) {
             Status status =
-                tempColl->getIndexCatalog()->createIndexOnEmptyCollection(_txn, *it).getStatus();
+                tempColl->getIndexCatalog()->createIndexOnEmptyCollection(_opCtx, *it).getStatus();
             if (!status.isOK()) {
                 if (status.code() == ErrorCodes::IndexAlreadyExists) {
                     continue;
@@ -520,11 +520,12 @@ void State::prepTempCollection() {
             }
             // Log the createIndex operation.
             string logNs = _config.tempNamespace.db() + ".system.indexes";
-            getGlobalServiceContext()->getOpObserver()->onCreateIndex(_txn, logNs, *it, false);
+            getGlobalServiceContext()->getOpObserver()->onCreateIndex(_opCtx, logNs, *it, false);
         }
         wuow.commit();
     }
-    MONGO_WRITE_CONFLICT_RETRY_LOOP_END(_txn, "M/R prepTempCollection", _config.tempNamespace.ns())
+    MONGO_WRITE_CONFLICT_RETRY_LOOP_END(
+        _opCtx, "M/R prepTempCollection", _config.tempNamespace.ns())
 }
 
 /**
@@ -605,7 +606,7 @@ void State::appendResults(BSONObjBuilder& final) {
  * Does post processing on output collection.
  * This may involve replacing, merging or reducing.
  */
-long long State::postProcessCollection(OperationContext* txn,
+long long State::postProcessCollection(OperationContext* opCtx,
                                        CurOp* curOp,
                                        ProgressMeterHolder& pm) {
     if (_onDisk == false || _config.outputOptions.outType == Config::INMEMORY)
@@ -613,22 +614,22 @@ long long State::postProcessCollection(OperationContext* txn,
 
     bool holdingGlobalLock = false;
     if (_config.outputOptions.outNonAtomic)
-        return postProcessCollectionNonAtomic(txn, curOp, pm, holdingGlobalLock);
+        return postProcessCollectionNonAtomic(opCtx, curOp, pm, holdingGlobalLock);
 
-    invariant(!txn->lockState()->isLocked());
+    invariant(!opCtx->lockState()->isLocked());
 
-    ScopedTransaction transaction(txn, MODE_X);
+    ScopedTransaction transaction(opCtx, MODE_X);
     // This must be global because we may write across different databases.
-    Lock::GlobalWrite lock(txn->lockState());
+    Lock::GlobalWrite lock(opCtx->lockState());
     holdingGlobalLock = true;
-    return postProcessCollectionNonAtomic(txn, curOp, pm, holdingGlobalLock);
+    return postProcessCollectionNonAtomic(opCtx, curOp, pm, holdingGlobalLock);
 }
 
 namespace {
 
 // Runs a count against the namespace specified by 'ns'. If the caller holds the global write lock,
 // then this function does not acquire any additional locks.
-unsigned long long _collectionCount(OperationContext* txn,
+unsigned long long _collectionCount(OperationContext* opCtx,
                                     const NamespaceString& nss,
                                     bool callerHoldsGlobalLock) {
     Collection* coll = nullptr;
@@ -637,32 +638,32 @@ unsigned long long _collectionCount(OperationContext* txn,
     // If the global write lock is held, we must avoid using AutoGetCollectionForRead as it may lead
     // to deadlock when waiting for a majority snapshot to be committed. See SERVER-24596.
     if (callerHoldsGlobalLock) {
-        Database* db = dbHolder().get(txn, nss.ns());
+        Database* db = dbHolder().get(opCtx, nss.ns());
         if (db) {
             coll = db->getCollection(nss);
         }
     } else {
-        ctx.emplace(txn, nss);
+        ctx.emplace(opCtx, nss);
         coll = ctx->getCollection();
     }
 
-    return coll ? coll->numRecords(txn) : 0;
+    return coll ? coll->numRecords(opCtx) : 0;
 }
 
 }  // namespace
 
-long long State::postProcessCollectionNonAtomic(OperationContext* txn,
+long long State::postProcessCollectionNonAtomic(OperationContext* opCtx,
                                                 CurOp* curOp,
                                                 ProgressMeterHolder& pm,
                                                 bool callerHoldsGlobalLock) {
     if (_config.outputOptions.finalNamespace == _config.tempNamespace)
-        return _collectionCount(txn, _config.outputOptions.finalNamespace, callerHoldsGlobalLock);
+        return _collectionCount(opCtx, _config.outputOptions.finalNamespace, callerHoldsGlobalLock);
 
     if (_config.outputOptions.outType == Config::REPLACE ||
-        _collectionCount(txn, _config.outputOptions.finalNamespace, callerHoldsGlobalLock) == 0) {
-        ScopedTransaction transaction(txn, MODE_X);
+        _collectionCount(opCtx, _config.outputOptions.finalNamespace, callerHoldsGlobalLock) == 0) {
+        ScopedTransaction transaction(opCtx, MODE_X);
         // This must be global because we may write across different databases.
-        Lock::GlobalWrite lock(txn->lockState());
+        Lock::GlobalWrite lock(opCtx->lockState());
         // replace: just rename from temp to final collection name, dropping previous collection
         _db.dropCollection(_config.outputOptions.finalNamespace.ns());
         BSONObj info;
@@ -680,17 +681,19 @@ long long State::postProcessCollectionNonAtomic(OperationContext* txn,
     } else if (_config.outputOptions.outType == Config::MERGE) {
         // merge: upsert new docs into old collection
         {
-            const auto count = _collectionCount(txn, _config.tempNamespace, callerHoldsGlobalLock);
-            stdx::lock_guard<Client> lk(*txn->getClient());
+            const auto count =
+                _collectionCount(opCtx, _config.tempNamespace, callerHoldsGlobalLock);
+            stdx::lock_guard<Client> lk(*opCtx->getClient());
             curOp->setMessage_inlock(
                 "m/r: merge post processing", "M/R Merge Post Processing Progress", count);
         }
         unique_ptr<DBClientCursor> cursor = _db.query(_config.tempNamespace.ns(), BSONObj());
         while (cursor->more()) {
-            ScopedTransaction scopedXact(txn, MODE_X);
-            Lock::DBLock lock(txn->lockState(), _config.outputOptions.finalNamespace.db(), MODE_X);
+            ScopedTransaction scopedXact(opCtx, MODE_X);
+            Lock::DBLock lock(
+                opCtx->lockState(), _config.outputOptions.finalNamespace.db(), MODE_X);
             BSONObj o = cursor->nextSafe();
-            Helpers::upsert(txn, _config.outputOptions.finalNamespace.ns(), o);
+            Helpers::upsert(opCtx, _config.outputOptions.finalNamespace.ns(), o);
             pm.hit();
         }
         _db.dropCollection(_config.tempNamespace.ns());
@@ -700,25 +703,26 @@ long long State::postProcessCollectionNonAtomic(OperationContext* txn,
         BSONList values;
 
         {
-            const auto count = _collectionCount(txn, _config.tempNamespace, callerHoldsGlobalLock);
-            stdx::lock_guard<Client> lk(*txn->getClient());
+            const auto count =
+                _collectionCount(opCtx, _config.tempNamespace, callerHoldsGlobalLock);
+            stdx::lock_guard<Client> lk(*opCtx->getClient());
             curOp->setMessage_inlock(
                 "m/r: reduce post processing", "M/R Reduce Post Processing Progress", count);
         }
         unique_ptr<DBClientCursor> cursor = _db.query(_config.tempNamespace.ns(), BSONObj());
         while (cursor->more()) {
-            ScopedTransaction transaction(txn, MODE_X);
+            ScopedTransaction transaction(opCtx, MODE_X);
             // This must be global because we may write across different databases.
-            Lock::GlobalWrite lock(txn->lockState());
+            Lock::GlobalWrite lock(opCtx->lockState());
             BSONObj temp = cursor->nextSafe();
             BSONObj old;
 
             bool found;
             {
-                OldClientContext tx(txn, _config.outputOptions.finalNamespace.ns());
+                OldClientContext tx(opCtx, _config.outputOptions.finalNamespace.ns());
                 Collection* coll =
                     getCollectionOrUassert(tx.db(), _config.outputOptions.finalNamespace);
-                found = Helpers::findOne(txn, coll, temp["_id"].wrap(), old, true);
+                found = Helpers::findOne(opCtx, coll, temp["_id"].wrap(), old, true);
             }
 
             if (found) {
@@ -726,18 +730,18 @@ long long State::postProcessCollectionNonAtomic(OperationContext* txn,
                 values.clear();
                 values.push_back(temp);
                 values.push_back(old);
-                Helpers::upsert(txn,
+                Helpers::upsert(opCtx,
                                 _config.outputOptions.finalNamespace.ns(),
                                 _config.reducer->finalReduce(values, _config.finalizer.get()));
             } else {
-                Helpers::upsert(txn, _config.outputOptions.finalNamespace.ns(), temp);
+                Helpers::upsert(opCtx, _config.outputOptions.finalNamespace.ns(), temp);
             }
             pm.hit();
         }
         pm.finished();
     }
 
-    return _collectionCount(txn, _config.outputOptions.finalNamespace, callerHoldsGlobalLock);
+    return _collectionCount(opCtx, _config.outputOptions.finalNamespace, callerHoldsGlobalLock);
 }
 
 /**
@@ -747,11 +751,11 @@ void State::insert(const NamespaceString& nss, const BSONObj& o) {
     verify(_onDisk);
 
     MONGO_WRITE_CONFLICT_RETRY_LOOP_BEGIN {
-        OldClientWriteContext ctx(_txn, nss.ns());
-        WriteUnitOfWork wuow(_txn);
+        OldClientWriteContext ctx(_opCtx, nss.ns());
+        WriteUnitOfWork wuow(_opCtx);
         uassert(ErrorCodes::PrimarySteppedDown,
                 "no longer primary",
-                repl::getGlobalReplicationCoordinator()->canAcceptWritesFor(_txn, nss));
+                repl::getGlobalReplicationCoordinator()->canAcceptWritesFor(_opCtx, nss));
         Collection* coll = getCollectionOrUassert(ctx.db(), nss);
 
         BSONObjBuilder b;
@@ -761,7 +765,7 @@ void State::insert(const NamespaceString& nss, const BSONObj& o) {
         b.appendElements(o);
         BSONObj bo = b.obj();
 
-        StatusWith<BSONObj> res = fixDocumentForInsert(_txn->getServiceContext(), bo);
+        StatusWith<BSONObj> res = fixDocumentForInsert(_opCtx->getServiceContext(), bo);
         uassertStatusOK(res.getStatus());
         if (!res.getValue().isEmpty()) {
             bo = res.getValue();
@@ -769,10 +773,10 @@ void State::insert(const NamespaceString& nss, const BSONObj& o) {
 
         // TODO: Consider whether to pass OpDebug for stats tracking under SERVER-23261.
         OpDebug* const nullOpDebug = nullptr;
-        uassertStatusOK(coll->insertDocument(_txn, bo, nullOpDebug, true));
+        uassertStatusOK(coll->insertDocument(_opCtx, bo, nullOpDebug, true));
         wuow.commit();
     }
-    MONGO_WRITE_CONFLICT_RETRY_LOOP_END(_txn, "M/R insert", nss.ns());
+    MONGO_WRITE_CONFLICT_RETRY_LOOP_END(_opCtx, "M/R insert", nss.ns());
 }
 
 /**
@@ -782,12 +786,12 @@ void State::_insertToInc(BSONObj& o) {
     verify(_onDisk);
 
     MONGO_WRITE_CONFLICT_RETRY_LOOP_BEGIN {
-        OldClientWriteContext ctx(_txn, _config.incLong.ns());
-        WriteUnitOfWork wuow(_txn);
+        OldClientWriteContext ctx(_opCtx, _config.incLong.ns());
+        WriteUnitOfWork wuow(_opCtx);
         Collection* coll = getCollectionOrUassert(ctx.db(), _config.incLong);
-        bool shouldReplicateWrites = _txn->writesAreReplicated();
-        _txn->setReplicatedWrites(false);
-        ON_BLOCK_EXIT(&OperationContext::setReplicatedWrites, _txn, shouldReplicateWrites);
+        bool shouldReplicateWrites = _opCtx->writesAreReplicated();
+        _opCtx->setReplicatedWrites(false);
+        ON_BLOCK_EXIT(&OperationContext::setReplicatedWrites, _opCtx, shouldReplicateWrites);
 
         // The documents inserted into the incremental collection are of the form
         // {"0": <key>, "1": <value>}, so we cannot call fixDocumentForInsert(o) here because the
@@ -804,14 +808,20 @@ void State::_insertToInc(BSONObj& o) {
 
         // TODO: Consider whether to pass OpDebug for stats tracking under SERVER-23261.
         OpDebug* const nullOpDebug = nullptr;
-        uassertStatusOK(coll->insertDocument(_txn, o, nullOpDebug, true, false));
+        uassertStatusOK(coll->insertDocument(_opCtx, o, nullOpDebug, true, false));
         wuow.commit();
     }
-    MONGO_WRITE_CONFLICT_RETRY_LOOP_END(_txn, "M/R insertToInc", _config.incLong.ns());
+    MONGO_WRITE_CONFLICT_RETRY_LOOP_END(_opCtx, "M/R insertToInc", _config.incLong.ns());
 }
 
-State::State(OperationContext* txn, const Config& c)
-    : _config(c), _db(txn), _useIncremental(true), _txn(txn), _size(0), _dupCount(0), _numEmits(0) {
+State::State(OperationContext* opCtx, const Config& c)
+    : _config(c),
+      _db(opCtx),
+      _useIncremental(true),
+      _opCtx(opCtx),
+      _size(0),
+      _dupCount(0),
+      _numEmits(0) {
     _temp.reset(new InMemory());
     _onDisk = _config.outputOptions.outType != Config::INMEMORY;
 }
@@ -849,9 +859,9 @@ void State::init() {
     const string userToken =
         AuthorizationSession::get(Client::getCurrent())->getAuthenticatedUserNamesToken();
     _scope.reset(getGlobalScriptEngine()->newScopeForCurrentThread());
-    _scope->registerOperation(_txn);
+    _scope->registerOperation(_opCtx);
     _scope->setLocalDB(_config.dbname);
-    _scope->loadStored(_txn, true);
+    _scope->loadStored(_opCtx, true);
 
     if (!_config.scopeSetup.isEmpty())
         _scope->init(&_config.scopeSetup);
@@ -1027,7 +1037,7 @@ BSONObj _nativeToTemp(const BSONObj& args, void* data) {
  * After calling this method, the temp collection will be completed.
  * If inline, the results will be in the in memory map
  */
-void State::finalReduce(OperationContext* txn, CurOp* curOp, ProgressMeterHolder& pm) {
+void State::finalReduce(OperationContext* opCtx, CurOp* curOp, ProgressMeterHolder& pm) {
     if (_jsMode) {
         // apply the reduce within JS
         if (_onDisk) {
@@ -1066,12 +1076,12 @@ void State::finalReduce(OperationContext* txn, CurOp* curOp, ProgressMeterHolder
     BSONObj sortKey = BSON("0" << 1);
 
     MONGO_WRITE_CONFLICT_RETRY_LOOP_BEGIN {
-        OldClientWriteContext incCtx(_txn, _config.incLong.ns());
-        WriteUnitOfWork wuow(_txn);
+        OldClientWriteContext incCtx(_opCtx, _config.incLong.ns());
+        WriteUnitOfWork wuow(_opCtx);
         Collection* incColl = getCollectionOrUassert(incCtx.db(), _config.incLong);
 
         bool foundIndex = false;
-        IndexCatalog::IndexIterator ii = incColl->getIndexCatalog()->getIndexIterator(_txn, true);
+        IndexCatalog::IndexIterator ii = incColl->getIndexCatalog()->getIndexIterator(_opCtx, true);
         // Iterate over incColl's indexes.
         while (ii.more()) {
             IndexDescriptor* currIndex = ii.next();
@@ -1085,28 +1095,28 @@ void State::finalReduce(OperationContext* txn, CurOp* curOp, ProgressMeterHolder
         verify(foundIndex);
         wuow.commit();
     }
-    MONGO_WRITE_CONFLICT_RETRY_LOOP_END(_txn, "finalReduce", _config.incLong.ns());
+    MONGO_WRITE_CONFLICT_RETRY_LOOP_END(_opCtx, "finalReduce", _config.incLong.ns());
 
-    unique_ptr<AutoGetCollectionForRead> ctx(new AutoGetCollectionForRead(_txn, _config.incLong));
+    unique_ptr<AutoGetCollectionForRead> ctx(new AutoGetCollectionForRead(_opCtx, _config.incLong));
 
     BSONObj prev;
     BSONList all;
 
     {
         const auto count = _db.count(_config.incLong.ns(), BSONObj(), QueryOption_SlaveOk);
-        stdx::lock_guard<Client> lk(*_txn->getClient());
+        stdx::lock_guard<Client> lk(*_opCtx->getClient());
         verify(pm ==
                curOp->setMessage_inlock("m/r: (3/3) final reduce to collection",
                                         "M/R: (3/3) Final Reduce Progress",
                                         count));
     }
 
-    const ExtensionsCallbackReal extensionsCallback(_txn, &_config.incLong);
+    const ExtensionsCallbackReal extensionsCallback(_opCtx, &_config.incLong);
 
     auto qr = stdx::make_unique<QueryRequest>(_config.incLong);
     qr->setSort(sortKey);
 
-    auto statusWithCQ = CanonicalQuery::canonicalize(txn, std::move(qr), extensionsCallback);
+    auto statusWithCQ = CanonicalQuery::canonicalize(opCtx, std::move(qr), extensionsCallback);
     verify(statusWithCQ.isOK());
     std::unique_ptr<CanonicalQuery> cq = std::move(statusWithCQ.getValue());
 
@@ -1114,7 +1124,7 @@ void State::finalReduce(OperationContext* txn, CurOp* curOp, ProgressMeterHolder
     invariant(coll);
 
     auto statusWithPlanExecutor = getExecutor(
-        _txn, coll, std::move(cq), PlanExecutor::YIELD_AUTO, QueryPlannerParams::NO_TABLE_SCAN);
+        _opCtx, coll, std::move(cq), PlanExecutor::YIELD_AUTO, QueryPlannerParams::NO_TABLE_SCAN);
     verify(statusWithPlanExecutor.isOK());
 
     unique_ptr<PlanExecutor> exec = std::move(statusWithPlanExecutor.getValue());
@@ -1130,7 +1140,7 @@ void State::finalReduce(OperationContext* txn, CurOp* curOp, ProgressMeterHolder
             // object is same as previous, add to array
             all.push_back(o);
             if (pm->hits() % 100 == 0) {
-                _txn->checkForInterrupt();
+                _opCtx->checkForInterrupt();
             }
             continue;
         }
@@ -1142,7 +1152,7 @@ void State::finalReduce(OperationContext* txn, CurOp* curOp, ProgressMeterHolder
         // reduce a finalize array
         finalReduce(all);
 
-        ctx.reset(new AutoGetCollectionForRead(_txn, _config.incLong));
+        ctx.reset(new AutoGetCollectionForRead(_opCtx, _config.incLong));
 
         all.clear();
         prev = o;
@@ -1152,7 +1162,7 @@ void State::finalReduce(OperationContext* txn, CurOp* curOp, ProgressMeterHolder
             uasserted(34375, "Plan executor killed during mapReduce final reduce");
         }
 
-        _txn->checkForInterrupt();
+        _opCtx->checkForInterrupt();
     }
 
     uassert(34428,
@@ -1162,7 +1172,7 @@ void State::finalReduce(OperationContext* txn, CurOp* curOp, ProgressMeterHolder
     ctx.reset();
     // reduce and finalize last array
     finalReduce(all);
-    ctx.reset(new AutoGetCollectionForRead(_txn, _config.incLong));
+    ctx.reset(new AutoGetCollectionForRead(_opCtx, _config.incLong));
 
     pm.finished();
 }
@@ -1247,7 +1257,7 @@ int State::_add(InMemory* im, const BSONObj& a) {
 void State::reduceAndSpillInMemoryStateIfNeeded() {
     // Make sure no DB locks are held, because this method manages its own locking and
     // write units of work.
-    invariant(!_txn->lockState()->isLocked());
+    invariant(!_opCtx->lockState()->isLocked());
 
     if (_jsMode) {
         // try to reduce if it is beneficial
@@ -1362,7 +1372,7 @@ public:
         addPrivilegesRequiredForMapReduce(this, dbname, cmdObj, out);
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmd,
              int,
@@ -1372,9 +1382,9 @@ public:
 
         boost::optional<DisableDocumentValidation> maybeDisableValidation;
         if (shouldBypassDocumentValidationForCommand(cmd))
-            maybeDisableValidation.emplace(txn);
+            maybeDisableValidation.emplace(opCtx);
 
-        auto client = txn->getClient();
+        auto client = opCtx->getClient();
 
         if (client->isInDirectClient()) {
             return appendCommandStatus(
@@ -1382,7 +1392,7 @@ public:
                 Status(ErrorCodes::IllegalOperation, "Cannot run mapReduce command from eval()"));
         }
 
-        auto curOp = CurOp::get(txn);
+        auto curOp = CurOp::get(opCtx);
 
         const Config config(dbname, cmd);
 
@@ -1404,7 +1414,7 @@ public:
         unique_ptr<RangePreserver> rangePreserver;
         ScopedCollectionMetadata collMetadata;
         {
-            AutoGetCollectionForRead ctx(txn, config.nss);
+            AutoGetCollectionForRead ctx(opCtx, config.nss);
 
             Collection* collection = ctx.getCollection();
             if (collection) {
@@ -1413,19 +1423,19 @@ public:
 
             // Get metadata before we check our version, to make sure it doesn't increment
             // in the meantime.  Need to do this in the same lock scope as the block.
-            if (ShardingState::get(txn)->needCollectionMetadata(txn, config.nss.ns())) {
-                collMetadata = CollectionShardingState::get(txn, config.nss)->getMetadata();
+            if (ShardingState::get(opCtx)->needCollectionMetadata(opCtx, config.nss.ns())) {
+                collMetadata = CollectionShardingState::get(opCtx, config.nss)->getMetadata();
             }
         }
 
         // Ensure that the RangePreserver is freed under the lock. This is necessary since the
         // RangePreserver's destructor unpins a ClientCursor, and access to the CursorManager must
         // be done under the lock.
-        ON_BLOCK_EXIT([txn, &config, &rangePreserver] {
+        ON_BLOCK_EXIT([opCtx, &config, &rangePreserver] {
             if (rangePreserver) {
                 // Be sure not to use AutoGetCollectionForRead here, since that has side-effects
                 // other than lock acquisition.
-                AutoGetCollection ctx(txn, config.nss, MODE_IS);
+                AutoGetCollection ctx(opCtx, config.nss, MODE_IS);
                 rangePreserver.reset();
             }
         });
@@ -1434,7 +1444,7 @@ public:
 
         BSONObjBuilder countsBuilder;
         BSONObjBuilder timingBuilder;
-        State state(txn, config);
+        State state(opCtx, config);
         if (!state.sourceExists()) {
             return appendCommandStatus(
                 result,
@@ -1444,7 +1454,7 @@ public:
         if (state.isOnDisk()) {
             // this means that it will be doing a write operation, make sure we are on Master
             // ideally this check should be in slaveOk(), but at that point config is not known
-            if (!repl::getGlobalReplicationCoordinator()->canAcceptWritesFor_UNSAFE(txn,
+            if (!repl::getGlobalReplicationCoordinator()->canAcceptWritesFor_UNSAFE(opCtx,
                                                                                     config.nss)) {
                 errmsg = "not master";
                 return false;
@@ -1460,7 +1470,7 @@ public:
             bool showTotal = true;
             if (state.config().filter.isEmpty()) {
                 const bool holdingGlobalLock = false;
-                const auto count = _collectionCount(txn, config.nss, holdingGlobalLock);
+                const auto count = _collectionCount(opCtx, config.nss, holdingGlobalLock);
                 progressTotal =
                     (config.limit && (unsigned)config.limit < count) ? config.limit : count;
             } else {
@@ -1469,7 +1479,7 @@ public:
                 progressTotal = 1;
             }
 
-            stdx::unique_lock<Client> lk(*txn->getClient());
+            stdx::unique_lock<Client> lk(*opCtx->getClient());
             ProgressMeter& progress(curOp->setMessage_inlock(
                 "m/r: (1/3) emit phase", "M/R: (1/3) Emit Progress", progressTotal));
             lk.unlock();
@@ -1488,18 +1498,18 @@ public:
                 // useful cursor.
 
                 // Need lock and context to use it
-                unique_ptr<ScopedTransaction> scopedXact(new ScopedTransaction(txn, MODE_IS));
-                unique_ptr<AutoGetDb> scopedAutoDb(new AutoGetDb(txn, config.nss.db(), MODE_S));
+                unique_ptr<ScopedTransaction> scopedXact(new ScopedTransaction(opCtx, MODE_IS));
+                unique_ptr<AutoGetDb> scopedAutoDb(new AutoGetDb(opCtx, config.nss.db(), MODE_S));
 
                 auto qr = stdx::make_unique<QueryRequest>(config.nss);
                 qr->setFilter(config.filter);
                 qr->setSort(config.sort);
                 qr->setCollation(config.collation);
 
-                const ExtensionsCallbackReal extensionsCallback(txn, &config.nss);
+                const ExtensionsCallbackReal extensionsCallback(opCtx, &config.nss);
 
                 auto statusWithCQ =
-                    CanonicalQuery::canonicalize(txn, std::move(qr), extensionsCallback);
+                    CanonicalQuery::canonicalize(opCtx, std::move(qr), extensionsCallback);
                 if (!statusWithCQ.isOK()) {
                     uasserted(17238, "Can't canonicalize query " + config.filter.toString());
                     return 0;
@@ -1513,7 +1523,7 @@ public:
                     invariant(coll);
 
                     auto statusWithPlanExecutor =
-                        getExecutor(txn, coll, std::move(cq), PlanExecutor::YIELD_AUTO);
+                        getExecutor(opCtx, coll, std::move(cq), PlanExecutor::YIELD_AUTO);
                     if (!statusWithPlanExecutor.isOK()) {
                         uasserted(17239,
                                   "Can't get executor for query " + config.filter.toString());
@@ -1524,8 +1534,8 @@ public:
                 }
 
                 {
-                    stdx::lock_guard<Client> lk(*txn->getClient());
-                    CurOp::get(txn)->setPlanSummary_inlock(Explain::getPlanSummary(exec.get()));
+                    stdx::lock_guard<Client> lk(*opCtx->getClient());
+                    CurOp::get(opCtx)->setPlanSummary_inlock(Explain::getPlanSummary(exec.get()));
                 }
 
                 Timer mt;
@@ -1568,8 +1578,8 @@ public:
 
                         state.reduceAndSpillInMemoryStateIfNeeded();
 
-                        scopedXact.reset(new ScopedTransaction(txn, MODE_IS));
-                        scopedAutoDb.reset(new AutoGetDb(txn, config.nss.db(), MODE_S));
+                        scopedXact.reset(new ScopedTransaction(opCtx, MODE_IS));
+                        scopedAutoDb.reset(new AutoGetDb(opCtx, config.nss.db(), MODE_S));
 
                         if (!exec->restoreState()) {
                             return appendCommandStatus(
@@ -1581,7 +1591,7 @@ public:
 
                         reduceTime += t.micros();
 
-                        txn->checkForInterrupt();
+                        opCtx->checkForInterrupt();
                     }
 
                     pm.hit();
@@ -1608,7 +1618,7 @@ public:
 
                 Collection* coll = scopedAutoDb->getDb()->getCollection(config.nss);
                 invariant(coll);  // 'exec' hasn't been killed, so collection must be alive.
-                coll->infoCache()->notifyOfQuery(txn, stats.indexesUsed);
+                coll->infoCache()->notifyOfQuery(opCtx, stats.indexesUsed);
 
                 if (curOp->shouldDBProfile()) {
                     BSONObjBuilder execStatsBob;
@@ -1618,7 +1628,7 @@ public:
             }
             pm.finished();
 
-            txn->checkForInterrupt();
+            opCtx->checkForInterrupt();
 
             // update counters
             countsBuilder.appendNumber("input", numInputs);
@@ -1630,7 +1640,7 @@ public:
             timingBuilder.append("emitLoop", t.millis());
 
             {
-                stdx::lock_guard<Client> lk(*txn->getClient());
+                stdx::lock_guard<Client> lk(*opCtx->getClient());
                 curOp->setMessage_inlock("m/r: (2/3) final reduce in memory",
                                          "M/R: (2/3) Final In-Memory Reduce Progress");
             }
@@ -1641,13 +1651,13 @@ public:
             // if not inline: dump the in memory map to inc collection, all data is on disk
             state.dumpToInc();
             // final reduce
-            state.finalReduce(txn, curOp, pm);
+            state.finalReduce(opCtx, curOp, pm);
             reduceTime += rt.micros();
 
             // Ensure the profile shows the source namespace. If the output was not inline, the
             // active namespace will be the temporary collection we inserted into.
             {
-                stdx::lock_guard<Client> lk(*txn->getClient());
+                stdx::lock_guard<Client> lk(*opCtx->getClient());
                 curOp->setNS_inlock(config.nss.ns());
             }
 
@@ -1655,7 +1665,7 @@ public:
             timingBuilder.appendNumber("reduceTime", reduceTime / 1000);
             timingBuilder.append("mode", state.jsMode() ? "js" : "mixed");
 
-            long long finalCount = state.postProcessCollection(txn, curOp, pm);
+            long long finalCount = state.postProcessCollection(opCtx, curOp, pm);
             state.appendResults(result);
 
             timingBuilder.appendNumber("total", t.millis());
@@ -1718,7 +1728,7 @@ public:
         actions.addAction(ActionType::internal);
         out->push_back(Privilege(ResourcePattern::forClusterResource(), actions));
     }
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int,
@@ -1734,7 +1744,7 @@ public:
 
         boost::optional<DisableDocumentValidation> maybeDisableValidation;
         if (shouldBypassDocumentValidationForCommand(cmdObj))
-            maybeDisableValidation.emplace(txn);
+            maybeDisableValidation.emplace(opCtx);
 
         ShardedConnectionInfo::addHook();
 
@@ -1754,10 +1764,10 @@ public:
             inputNS = NamespaceString(dbname, shardedOutputCollection).ns();
         }
 
-        CurOp* curOp = CurOp::get(txn);
+        CurOp* curOp = CurOp::get(opCtx);
 
         Config config(dbname, cmdObj.firstElement().embeddedObjectUserCheck());
-        State state(txn, config);
+        State state(opCtx, config);
         state.init();
 
         // no need for incremental collection because records are already sorted
@@ -1767,7 +1777,7 @@ public:
         BSONObj shardCounts = cmdObj["shardCounts"].embeddedObjectUserCheck();
         BSONObj counts = cmdObj["counts"].embeddedObjectUserCheck();
 
-        stdx::unique_lock<Client> lk(*txn->getClient());
+        stdx::unique_lock<Client> lk(*opCtx->getClient());
         ProgressMeterHolder pm(curOp->setMessage_inlock("m/r: merge sort and reduce",
                                                         "M/R Merge Sort and Reduce Progress"));
         lk.unlock();
@@ -1781,7 +1791,7 @@ public:
                 std::string server = e.fieldName();
                 servers.insert(server);
 
-                uassertStatusOK(Grid::get(txn)->shardRegistry()->getShard(txn, server));
+                uassertStatusOK(Grid::get(opCtx)->shardRegistry()->getShard(opCtx, server));
             }
         }
 
@@ -1801,7 +1811,7 @@ public:
                 result.append("result", config.outputOptions.collectionName);
         }
 
-        auto scopedDbStatus = ScopedShardDatabase::getExisting(txn, dbname);
+        auto scopedDbStatus = ScopedShardDatabase::getExisting(opCtx, dbname);
         if (!scopedDbStatus.isOK()) {
             return appendCommandStatus(result, scopedDbStatus.getStatus());
         }
@@ -1812,11 +1822,11 @@ public:
 
         if (confOut->isSharded(config.outputOptions.finalNamespace.ns())) {
             shared_ptr<ChunkManager> cm =
-                confOut->getChunkManager(txn, config.outputOptions.finalNamespace.ns());
+                confOut->getChunkManager(opCtx, config.outputOptions.finalNamespace.ns());
 
             // Fetch result from other shards 1 chunk at a time. It would be better to do just one
             // big $or query, but then the sorting would not be efficient.
-            const string shardName = ShardingState::get(txn)->getShardName();
+            const string shardName = ShardingState::get(opCtx)->getShardName();
             const ChunkMap& chunkMap = cm->getChunkMap();
 
             for (ChunkMap::const_iterator it = chunkMap.begin(); it != chunkMap.end(); ++it) {
@@ -1846,7 +1856,7 @@ public:
             BSONObj sortKey = BSON("_id" << 1);
             ParallelSortClusteredCursor cursor(
                 servers, inputNS, Query(query).sort(sortKey), QueryOption_NoCursorTimeout);
-            cursor.init(txn);
+            cursor.init(opCtx);
             int chunkSize = 0;
 
             while (cursor.more() || !values.empty()) {
@@ -1890,7 +1900,7 @@ public:
 
         result.append("chunkSizes", chunkSizes.arr());
 
-        long long outputCount = state.postProcessCollection(txn, curOp, pm);
+        long long outputCount = state.postProcessCollection(opCtx, curOp, pm);
         state.appendResults(result);
 
         BSONObjBuilder countsB(32);
diff --git a/src/mongo/db/commands/mr.h b/src/mongo/db/commands/mr.h
index aa729f49e7f..15baf5e8fb9 100644
--- a/src/mongo/db/commands/mr.h
+++ b/src/mongo/db/commands/mr.h
@@ -260,9 +260,9 @@ public:
 class State {
 public:
     /**
-     * txn must outlive this State.
+     * opCtx must outlive this State.
      */
-    State(OperationContext* txn, const Config& c);
+    State(OperationContext* opCtx, const Config& c);
     ~State();
 
     void init();
@@ -305,7 +305,7 @@ public:
 
     void finalReduce(BSONList& values);
 
-    void finalReduce(OperationContext* txn, CurOp* op, ProgressMeterHolder& pm);
+    void finalReduce(OperationContext* opCtx, CurOp* op, ProgressMeterHolder& pm);
 
     // ------- cleanup/data positioning ----------
 
@@ -317,8 +317,8 @@ public:
     /**
        @return number objects in collection
      */
-    long long postProcessCollection(OperationContext* txn, CurOp* op, ProgressMeterHolder& pm);
-    long long postProcessCollectionNonAtomic(OperationContext* txn,
+    long long postProcessCollection(OperationContext* opCtx, CurOp* op, ProgressMeterHolder& pm);
+    long long postProcessCollectionNonAtomic(OperationContext* opCtx,
                                              CurOp* op,
                                              ProgressMeterHolder& pm,
                                              bool callerHoldsGlobalLock);
@@ -388,7 +388,7 @@ protected:
      */
     int _add(InMemory* im, const BSONObj& a);
 
-    OperationContext* _txn;
+    OperationContext* _opCtx;
     std::unique_ptr<Scope> _scope;
     bool _onDisk;  // if the end result of this map reduce is disk or not
 
diff --git a/src/mongo/db/commands/oplog_note.cpp b/src/mongo/db/commands/oplog_note.cpp
index 35062313941..39d3d175ff0 100644
--- a/src/mongo/db/commands/oplog_note.cpp
+++ b/src/mongo/db/commands/oplog_note.cpp
@@ -69,7 +69,7 @@ public:
         }
         return Status::OK();
     }
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const string& dbname,
                      BSONObj& cmdObj,
                      int,
@@ -87,11 +87,11 @@ public:
             return appendCommandStatus(result, status);
         }
 
-        ScopedTransaction scopedXact(txn, MODE_X);
-        Lock::GlobalWrite globalWrite(txn->lockState());
+        ScopedTransaction scopedXact(opCtx, MODE_X);
+        Lock::GlobalWrite globalWrite(opCtx->lockState());
 
-        WriteUnitOfWork wuow(txn);
-        getGlobalServiceContext()->getOpObserver()->onOpMessage(txn, dataElement.Obj());
+        WriteUnitOfWork wuow(opCtx);
+        getGlobalServiceContext()->getOpObserver()->onOpMessage(opCtx, dataElement.Obj());
         wuow.commit();
         return true;
     }
diff --git a/src/mongo/db/commands/parallel_collection_scan.cpp b/src/mongo/db/commands/parallel_collection_scan.cpp
index 41689016961..df783b46062 100644
--- a/src/mongo/db/commands/parallel_collection_scan.cpp
+++ b/src/mongo/db/commands/parallel_collection_scan.cpp
@@ -85,7 +85,7 @@ public:
         return Status(ErrorCodes::Unauthorized, "Unauthorized");
     }
 
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const string& dbname,
                      BSONObj& cmdObj,
                      int options,
@@ -93,7 +93,7 @@ public:
                      BSONObjBuilder& result) {
         const NamespaceString ns(parseNsCollectionRequired(dbname, cmdObj));
 
-        AutoGetCollectionForRead ctx(txn, ns);
+        AutoGetCollectionForRead ctx(opCtx, ns);
 
         Collection* collection = ctx.getCollection();
         if (!collection)
@@ -111,7 +111,7 @@ public:
                                                   << " was: "
                                                   << numCursors));
 
-        auto iterators = collection->getManyCursors(txn);
+        auto iterators = collection->getManyCursors(opCtx);
         if (iterators.size() < numCursors) {
             numCursors = iterators.size();
         }
@@ -120,11 +120,11 @@ public:
         for (size_t i = 0; i < numCursors; i++) {
             unique_ptr<WorkingSet> ws = make_unique<WorkingSet>();
             unique_ptr<MultiIteratorStage> mis =
-                make_unique<MultiIteratorStage>(txn, ws.get(), collection);
+                make_unique<MultiIteratorStage>(opCtx, ws.get(), collection);
 
             // Takes ownership of 'ws' and 'mis'.
             auto statusWithPlanExecutor = PlanExecutor::make(
-                txn, std::move(ws), std::move(mis), collection, PlanExecutor::YIELD_AUTO);
+                opCtx, std::move(ws), std::move(mis), collection, PlanExecutor::YIELD_AUTO);
             invariant(statusWithPlanExecutor.isOK());
             execs.push_back(std::move(statusWithPlanExecutor.getValue()));
         }
@@ -152,9 +152,9 @@ public:
                 auto pinnedCursor = collection->getCursorManager()->registerCursor(
                     {exec.release(),
                      ns.ns(),
-                     txn->recoveryUnit()->isReadingFromMajorityCommittedSnapshot()});
+                     opCtx->recoveryUnit()->isReadingFromMajorityCommittedSnapshot()});
                 pinnedCursor.getCursor()->setLeftoverMaxTimeMicros(
-                    txn->getRemainingMaxTimeMicros());
+                    opCtx->getRemainingMaxTimeMicros());
 
                 BSONObjBuilder threadResult;
                 appendCursorResponseObject(
diff --git a/src/mongo/db/commands/parameters.cpp b/src/mongo/db/commands/parameters.cpp
index a3c252d050a..f2e10dac2b5 100644
--- a/src/mongo/db/commands/parameters.cpp
+++ b/src/mongo/db/commands/parameters.cpp
@@ -88,7 +88,7 @@ public:
         appendParameterNames(help);
         help << "{ getParameter:'*' } to get everything\n";
     }
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int,
@@ -101,7 +101,7 @@ public:
         const ServerParameter::Map& m = ServerParameterSet::getGlobal()->getMap();
         for (ServerParameter::Map::const_iterator i = m.begin(); i != m.end(); ++i) {
             if (all || cmdObj.hasElement(i->first.c_str())) {
-                i->second->append(txn, result, i->second->name());
+                i->second->append(opCtx, result, i->second->name());
             }
         }
 
@@ -137,7 +137,7 @@ public:
         help << "{ setParameter:1, <param>:<value> }\n";
         appendParameterNames(help);
     }
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int,
@@ -213,7 +213,7 @@ public:
             }
 
             if (numSet == 0) {
-                foundParameter->second->append(txn, result, "was");
+                foundParameter->second->append(opCtx, result, "was");
             }
 
             Status status = foundParameter->second->set(parameter);
@@ -247,7 +247,7 @@ class LogLevelSetting : public ServerParameter {
 public:
     LogLevelSetting() : ServerParameter(ServerParameterSet::getGlobal(), "logLevel") {}
 
-    virtual void append(OperationContext* txn, BSONObjBuilder& b, const std::string& name) {
+    virtual void append(OperationContext* opCtx, BSONObjBuilder& b, const std::string& name) {
         b << name << globalLogDomain()->getMinimumLogSeverity().toInt();
     }
 
@@ -290,7 +290,7 @@ public:
     LogComponentVerbositySetting()
         : ServerParameter(ServerParameterSet::getGlobal(), "logComponentVerbosity") {}
 
-    virtual void append(OperationContext* txn, BSONObjBuilder& b, const std::string& name) {
+    virtual void append(OperationContext* opCtx, BSONObjBuilder& b, const std::string& name) {
         BSONObj currentSettings;
         _get(&currentSettings);
         b << name << currentSettings;
@@ -459,7 +459,7 @@ public:
         }
     }
 
-    virtual void append(OperationContext* txn, BSONObjBuilder& b, const std::string& name) {
+    virtual void append(OperationContext* opCtx, BSONObjBuilder& b, const std::string& name) {
         b << name << sslModeStr();
     }
 
@@ -530,7 +530,7 @@ public:
         }
     }
 
-    virtual void append(OperationContext* txn, BSONObjBuilder& b, const std::string& name) {
+    virtual void append(OperationContext* opCtx, BSONObjBuilder& b, const std::string& name) {
         b << name << clusterAuthModeStr();
     }
 
@@ -607,7 +607,7 @@ public:
     AutomationServiceDescriptor()
         : ServerParameter(ServerParameterSet::getGlobal(), kName.toString(), true, true) {}
 
-    virtual void append(OperationContext* txn,
+    virtual void append(OperationContext* opCtx,
                         BSONObjBuilder& builder,
                         const std::string& name) override {
         const stdx::lock_guard<stdx::mutex> lock(_mutex);
diff --git a/src/mongo/db/commands/pipeline_command.cpp b/src/mongo/db/commands/pipeline_command.cpp
index 0f07e38c830..4fcfb97f574 100644
--- a/src/mongo/db/commands/pipeline_command.cpp
+++ b/src/mongo/db/commands/pipeline_command.cpp
@@ -88,7 +88,7 @@ namespace {
  * namespace used in the returned cursor. In the case of views, this can be different from that
  * in 'request'.
  */
-bool handleCursorCommand(OperationContext* txn,
+bool handleCursorCommand(OperationContext* opCtx,
                          const string& nsForCursor,
                          ClientCursor* cursor,
                          PlanExecutor* exec,
@@ -150,16 +150,16 @@ bool handleCursorCommand(OperationContext* txn,
     if (cursor) {
         // If a time limit was set on the pipeline, remaining time is "rolled over" to the
         // cursor (for use by future getmore ops).
-        cursor->setLeftoverMaxTimeMicros(txn->getRemainingMaxTimeMicros());
+        cursor->setLeftoverMaxTimeMicros(opCtx->getRemainingMaxTimeMicros());
 
-        CurOp::get(txn)->debug().cursorid = cursor->cursorid();
+        CurOp::get(opCtx)->debug().cursorid = cursor->cursorid();
 
         // Cursor needs to be in a saved state while we yield locks for getmore. State
         // will be restored in getMore().
         exec->saveState();
         exec->detachFromOperationContext();
     } else {
-        CurOp::get(txn)->debug().cursorExhausted = true;
+        CurOp::get(opCtx)->debug().cursorExhausted = true;
     }
 
     const long long cursorId = cursor ? cursor->cursorid() : 0LL;
@@ -169,12 +169,12 @@ bool handleCursorCommand(OperationContext* txn,
 }
 
 StatusWith<StringMap<ExpressionContext::ResolvedNamespace>> resolveInvolvedNamespaces(
-    OperationContext* txn, const AggregationRequest& request) {
+    OperationContext* opCtx, const AggregationRequest& request) {
     // We intentionally do not drop and reacquire our DB lock after resolving the view definition in
     // order to prevent the definition for any view namespaces we've already resolved from changing.
     // This is necessary to prevent a cycle from being formed among the view definitions cached in
     // 'resolvedNamespaces' because we won't re-resolve a view namespace we've already encountered.
-    AutoGetDb autoDb(txn, request.getNamespaceString().db(), MODE_IS);
+    AutoGetDb autoDb(opCtx, request.getNamespaceString().db(), MODE_IS);
     Database* const db = autoDb.getDb();
     ViewCatalog* viewCatalog = db ? db->getViewCatalog() : nullptr;
 
@@ -199,9 +199,9 @@ StatusWith<StringMap<ExpressionContext::ResolvedNamespace>> resolveInvolvedNames
             // pipeline because 'involvedNs' doesn't refer to a view namespace in our consistent
             // snapshot of the view catalog.
             resolvedNamespaces[involvedNs.coll()] = {involvedNs, std::vector<BSONObj>{}};
-        } else if (viewCatalog->lookup(txn, involvedNs.ns())) {
+        } else if (viewCatalog->lookup(opCtx, involvedNs.ns())) {
             // If 'involvedNs' refers to a view namespace, then we resolve its definition.
-            auto resolvedView = viewCatalog->resolveView(txn, involvedNs);
+            auto resolvedView = viewCatalog->resolveView(opCtx, involvedNs);
             if (!resolvedView.isOK()) {
                 return {ErrorCodes::FailedToParse,
                         str::stream() << "Failed to resolve view '" << involvedNs.ns() << "': "
@@ -265,7 +265,7 @@ boost::intrusive_ptr<Pipeline> reparsePipeline(
  * Returns Status::OK if each view namespace in 'pipeline' has a default collator equivalent to
  * 'collator'. Otherwise, returns ErrorCodes::OptionNotSupportedOnView.
  */
-Status collatorCompatibleWithPipeline(OperationContext* txn,
+Status collatorCompatibleWithPipeline(OperationContext* opCtx,
                                       Database* db,
                                       const CollatorInterface* collator,
                                       const intrusive_ptr<Pipeline> pipeline) {
@@ -277,7 +277,7 @@ Status collatorCompatibleWithPipeline(OperationContext* txn,
             continue;
         }
 
-        auto view = db->getViewCatalog()->lookup(txn, potentialViewNs.ns());
+        auto view = db->getViewCatalog()->lookup(opCtx, potentialViewNs.ns());
         if (!view) {
             continue;
         }
@@ -339,7 +339,7 @@ public:
         return AuthorizationSession::get(client)->checkAuthForAggregate(nss, cmdObj);
     }
 
-    bool runParsed(OperationContext* txn,
+    bool runParsed(OperationContext* opCtx,
                    const NamespaceString& origNss,
                    const AggregationRequest& request,
                    BSONObj& cmdObj,
@@ -351,14 +351,14 @@ public:
         // Parse the user-specified collation, if any.
         std::unique_ptr<CollatorInterface> userSpecifiedCollator = request.getCollation().isEmpty()
             ? nullptr
-            : uassertStatusOK(CollatorFactoryInterface::get(txn->getServiceContext())
+            : uassertStatusOK(CollatorFactoryInterface::get(opCtx->getServiceContext())
                                   ->makeFromBSON(request.getCollation()));
 
         boost::optional<ClientCursorPin> pin;  // either this OR the exec will be non-null
         unique_ptr<PlanExecutor> exec;
         boost::intrusive_ptr<ExpressionContext> expCtx;
         boost::intrusive_ptr<Pipeline> pipeline;
-        auto curOp = CurOp::get(txn);
+        auto curOp = CurOp::get(opCtx);
         {
             // This will throw if the sharding version for this connection is out of date. If the
             // namespace is a view, the lock will be released before re-running the aggregation.
@@ -367,7 +367,7 @@ public:
             // same sharding version that we synchronize on here. This is also why we always need to
             // create a ClientCursor even when we aren't outputting to a cursor. See the comment on
             // ShardFilterStage for more details.
-            AutoGetCollectionOrViewForRead ctx(txn, nss);
+            AutoGetCollectionOrViewForRead ctx(opCtx, nss);
             Collection* collection = ctx.getCollection();
 
             // If this is a view, resolve it by finding the underlying collection and stitching view
@@ -390,7 +390,7 @@ public:
                 }
 
                 auto viewDefinition =
-                    ViewShardingCheck::getResolvedViewIfSharded(txn, ctx.getDb(), ctx.getView());
+                    ViewShardingCheck::getResolvedViewIfSharded(opCtx, ctx.getDb(), ctx.getView());
                 if (!viewDefinition.isOK()) {
                     return appendCommandStatus(result, viewDefinition.getStatus());
                 }
@@ -400,7 +400,7 @@ public:
                     return false;
                 }
 
-                auto resolvedView = ctx.getDb()->getViewCatalog()->resolveView(txn, nss);
+                auto resolvedView = ctx.getDb()->getViewCatalog()->resolveView(opCtx, nss);
                 if (!resolvedView.isOK()) {
                     return appendCommandStatus(result, resolvedView.getStatus());
                 }
@@ -425,11 +425,11 @@ public:
                 newRequest.getValue().setCollation(collationSpec);
 
                 bool status = runParsed(
-                    txn, origNss, newRequest.getValue(), newCmd.getValue(), errmsg, result);
+                    opCtx, origNss, newRequest.getValue(), newCmd.getValue(), errmsg, result);
                 {
                     // Set the namespace of the curop back to the view namespace so ctx records
                     // stats on this view namespace on destruction.
-                    stdx::lock_guard<Client> lk(*txn->getClient());
+                    stdx::lock_guard<Client> lk(*opCtx->getClient());
                     curOp->setNS_inlock(nss.ns());
                 }
                 return status;
@@ -449,10 +449,10 @@ public:
             }
 
             expCtx.reset(
-                new ExpressionContext(txn,
+                new ExpressionContext(opCtx,
                                       request,
                                       std::move(collatorToUse),
-                                      uassertStatusOK(resolveInvolvedNamespaces(txn, request))));
+                                      uassertStatusOK(resolveInvolvedNamespaces(opCtx, request))));
             expCtx->tempDir = storageGlobalParams.dbpath + "/_tmp";
 
             // Parse the pipeline.
@@ -465,7 +465,7 @@ public:
             // Check that the view's collation matches the collation of any views involved
             // in the pipeline.
             auto pipelineCollationStatus =
-                collatorCompatibleWithPipeline(txn, ctx.getDb(), expCtx->getCollator(), pipeline);
+                collatorCompatibleWithPipeline(opCtx, ctx.getDb(), expCtx->getCollator(), pipeline);
             if (!pipelineCollationStatus.isOK()) {
                 return appendCommandStatus(result, pipelineCollationStatus);
             }
@@ -488,19 +488,22 @@ public:
             // ('ws') and the PipelineProxyStage ('proxy') will be owned by the created
             // PlanExecutor.
             auto ws = make_unique<WorkingSet>();
-            auto proxy = make_unique<PipelineProxyStage>(txn, pipeline, ws.get());
+            auto proxy = make_unique<PipelineProxyStage>(opCtx, pipeline, ws.get());
 
             auto statusWithPlanExecutor = (NULL == collection)
                 ? PlanExecutor::make(
-                      txn, std::move(ws), std::move(proxy), nss.ns(), PlanExecutor::YIELD_MANUAL)
-                : PlanExecutor::make(
-                      txn, std::move(ws), std::move(proxy), collection, PlanExecutor::YIELD_MANUAL);
+                      opCtx, std::move(ws), std::move(proxy), nss.ns(), PlanExecutor::YIELD_MANUAL)
+                : PlanExecutor::make(opCtx,
+                                     std::move(ws),
+                                     std::move(proxy),
+                                     collection,
+                                     PlanExecutor::YIELD_MANUAL);
             invariant(statusWithPlanExecutor.isOK());
             exec = std::move(statusWithPlanExecutor.getValue());
 
             {
                 auto planSummary = Explain::getPlanSummary(exec.get());
-                stdx::lock_guard<Client> lk(*txn->getClient());
+                stdx::lock_guard<Client> lk(*opCtx->getClient());
                 curOp->setPlanSummary_inlock(std::move(planSummary));
             }
 
@@ -509,7 +512,7 @@ public:
                 pin.emplace(collection->getCursorManager()->registerCursor(
                     {exec.release(),
                      nss.ns(),
-                     txn->recoveryUnit()->isReadingFromMajorityCommittedSnapshot(),
+                     opCtx->recoveryUnit()->isReadingFromMajorityCommittedSnapshot(),
                      0,
                      cmdObj.getOwned(),
                      isAggCursor}));
@@ -533,7 +536,7 @@ public:
                 result << "stages" << Value(pipeline->writeExplainOps());
             } else {
                 // Cursor must be specified, if explain is not.
-                keepCursor = handleCursorCommand(txn,
+                keepCursor = handleCursorCommand(opCtx,
                                                  origNss.ns(),
                                                  pin ? pin->getCursor() : nullptr,
                                                  pin ? pin->getCursor()->getExecutor() : exec.get(),
@@ -556,8 +559,8 @@ public:
                 // AutoGetCollectionForRead.  AutoGetCollectionForRead will throw if the
                 // sharding version is out of date, and we don't care if the sharding version
                 // has changed.
-                Lock::DBLock dbLock(txn->lockState(), nss.db(), MODE_IS);
-                Lock::CollectionLock collLock(txn->lockState(), nss.ns(), MODE_IS);
+                Lock::DBLock dbLock(opCtx->lockState(), nss.db(), MODE_IS);
+                Lock::CollectionLock collLock(opCtx->lockState(), nss.ns(), MODE_IS);
                 if (keepCursor) {
                     pin->release();
                 } else {
@@ -567,8 +570,8 @@ public:
         } catch (...) {
             // On our way out of scope, we clean up our ClientCursorPin if needed.
             if (pin) {
-                Lock::DBLock dbLock(txn->lockState(), nss.db(), MODE_IS);
-                Lock::CollectionLock collLock(txn->lockState(), nss.ns(), MODE_IS);
+                Lock::DBLock dbLock(opCtx->lockState(), nss.db(), MODE_IS);
+                Lock::CollectionLock collLock(opCtx->lockState(), nss.ns(), MODE_IS);
                 pin->deleteUnderlying();
             }
             throw;
@@ -577,7 +580,7 @@ public:
         return appendCommandStatus(result, Status::OK());
     }
 
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const string& db,
                      BSONObj& cmdObj,
                      int options,
@@ -607,7 +610,7 @@ public:
                        "http://dochub.mongodb.org/core/3.4-feature-compatibility."));
         }
 
-        return runParsed(txn, nss, request.getValue(), cmdObj, errmsg, result);
+        return runParsed(opCtx, nss, request.getValue(), cmdObj, errmsg, result);
     }
 };
 
diff --git a/src/mongo/db/commands/plan_cache_commands.cpp b/src/mongo/db/commands/plan_cache_commands.cpp
index 67b244d6bb3..4cd4ca26992 100644
--- a/src/mongo/db/commands/plan_cache_commands.cpp
+++ b/src/mongo/db/commands/plan_cache_commands.cpp
@@ -58,7 +58,7 @@ using namespace mongo;
 /**
  * Retrieves a collection's plan cache from the database.
  */
-static Status getPlanCache(OperationContext* txn,
+static Status getPlanCache(OperationContext* opCtx,
                            Collection* collection,
                            const string& ns,
                            PlanCache** planCacheOut) {
@@ -110,14 +110,14 @@ PlanCacheCommand::PlanCacheCommand(const string& name,
                                    ActionType actionType)
     : Command(name), helpText(helpText), actionType(actionType) {}
 
-bool PlanCacheCommand::run(OperationContext* txn,
+bool PlanCacheCommand::run(OperationContext* opCtx,
                            const string& dbname,
                            BSONObj& cmdObj,
                            int options,
                            string& errmsg,
                            BSONObjBuilder& result) {
     const NamespaceString nss(parseNsCollectionRequired(dbname, cmdObj));
-    Status status = runPlanCacheCommand(txn, nss.ns(), cmdObj, &result);
+    Status status = runPlanCacheCommand(opCtx, nss.ns(), cmdObj, &result);
     return appendCommandStatus(result, status);
 }
 
@@ -152,7 +152,7 @@ Status PlanCacheCommand::checkAuthForCommand(Client* client,
 }
 
 // static
-StatusWith<unique_ptr<CanonicalQuery>> PlanCacheCommand::canonicalize(OperationContext* txn,
+StatusWith<unique_ptr<CanonicalQuery>> PlanCacheCommand::canonicalize(OperationContext* opCtx,
                                                                       const string& ns,
                                                                       const BSONObj& cmdObj) {
     // query - required
@@ -208,8 +208,8 @@ StatusWith<unique_ptr<CanonicalQuery>> PlanCacheCommand::canonicalize(OperationC
     qr->setSort(sortObj);
     qr->setProj(projObj);
     qr->setCollation(collationObj);
-    const ExtensionsCallbackReal extensionsCallback(txn, &nss);
-    auto statusWithCQ = CanonicalQuery::canonicalize(txn, std::move(qr), extensionsCallback);
+    const ExtensionsCallbackReal extensionsCallback(opCtx, &nss);
+    auto statusWithCQ = CanonicalQuery::canonicalize(opCtx, std::move(qr), extensionsCallback);
     if (!statusWithCQ.isOK()) {
         return statusWithCQ.getStatus();
     }
@@ -222,15 +222,15 @@ PlanCacheListQueryShapes::PlanCacheListQueryShapes()
                        "Displays all query shapes in a collection.",
                        ActionType::planCacheRead) {}
 
-Status PlanCacheListQueryShapes::runPlanCacheCommand(OperationContext* txn,
+Status PlanCacheListQueryShapes::runPlanCacheCommand(OperationContext* opCtx,
                                                      const string& ns,
                                                      BSONObj& cmdObj,
                                                      BSONObjBuilder* bob) {
     // This is a read lock. The query cache is owned by the collection.
-    AutoGetCollectionForRead ctx(txn, NamespaceString(ns));
+    AutoGetCollectionForRead ctx(opCtx, NamespaceString(ns));
 
     PlanCache* planCache;
-    Status status = getPlanCache(txn, ctx.getCollection(), ns, &planCache);
+    Status status = getPlanCache(opCtx, ctx.getCollection(), ns, &planCache);
     if (!status.isOK()) {
         // No collection - return results with empty shapes array.
         BSONArrayBuilder arrayBuilder(bob->subarrayStart("shapes"));
@@ -274,24 +274,24 @@ PlanCacheClear::PlanCacheClear()
                        "Drops one or all cached queries in a collection.",
                        ActionType::planCacheWrite) {}
 
-Status PlanCacheClear::runPlanCacheCommand(OperationContext* txn,
+Status PlanCacheClear::runPlanCacheCommand(OperationContext* opCtx,
                                            const std::string& ns,
                                            BSONObj& cmdObj,
                                            BSONObjBuilder* bob) {
     // This is a read lock. The query cache is owned by the collection.
-    AutoGetCollectionForRead ctx(txn, NamespaceString(ns));
+    AutoGetCollectionForRead ctx(opCtx, NamespaceString(ns));
 
     PlanCache* planCache;
-    Status status = getPlanCache(txn, ctx.getCollection(), ns, &planCache);
+    Status status = getPlanCache(opCtx, ctx.getCollection(), ns, &planCache);
     if (!status.isOK()) {
         // No collection - nothing to do. Return OK status.
         return Status::OK();
     }
-    return clear(txn, planCache, ns, cmdObj);
+    return clear(opCtx, planCache, ns, cmdObj);
 }
 
 // static
-Status PlanCacheClear::clear(OperationContext* txn,
+Status PlanCacheClear::clear(OperationContext* opCtx,
                              PlanCache* planCache,
                              const string& ns,
                              const BSONObj& cmdObj) {
@@ -302,7 +302,7 @@ Status PlanCacheClear::clear(OperationContext* txn,
     // - clear plans for single query shape when a query shape is described in the
     //   command arguments.
     if (cmdObj.hasField("query")) {
-        auto statusWithCQ = PlanCacheCommand::canonicalize(txn, ns, cmdObj);
+        auto statusWithCQ = PlanCacheCommand::canonicalize(opCtx, ns, cmdObj);
         if (!statusWithCQ.isOK()) {
             return statusWithCQ.getStatus();
         }
@@ -351,30 +351,30 @@ PlanCacheListPlans::PlanCacheListPlans()
                        "Displays the cached plans for a query shape.",
                        ActionType::planCacheRead) {}
 
-Status PlanCacheListPlans::runPlanCacheCommand(OperationContext* txn,
+Status PlanCacheListPlans::runPlanCacheCommand(OperationContext* opCtx,
                                                const std::string& ns,
                                                BSONObj& cmdObj,
                                                BSONObjBuilder* bob) {
-    AutoGetCollectionForRead ctx(txn, NamespaceString(ns));
+    AutoGetCollectionForRead ctx(opCtx, NamespaceString(ns));
 
     PlanCache* planCache;
-    Status status = getPlanCache(txn, ctx.getCollection(), ns, &planCache);
+    Status status = getPlanCache(opCtx, ctx.getCollection(), ns, &planCache);
     if (!status.isOK()) {
         // No collection - return empty plans array.
         BSONArrayBuilder plansBuilder(bob->subarrayStart("plans"));
         plansBuilder.doneFast();
         return Status::OK();
     }
-    return list(txn, *planCache, ns, cmdObj, bob);
+    return list(opCtx, *planCache, ns, cmdObj, bob);
 }
 
 // static
-Status PlanCacheListPlans::list(OperationContext* txn,
+Status PlanCacheListPlans::list(OperationContext* opCtx,
                                 const PlanCache& planCache,
                                 const std::string& ns,
                                 const BSONObj& cmdObj,
                                 BSONObjBuilder* bob) {
-    auto statusWithCQ = canonicalize(txn, ns, cmdObj);
+    auto statusWithCQ = canonicalize(opCtx, ns, cmdObj);
     if (!statusWithCQ.isOK()) {
         return statusWithCQ.getStatus();
     }
diff --git a/src/mongo/db/commands/plan_cache_commands.h b/src/mongo/db/commands/plan_cache_commands.h
index 1b6afaf2171..881bf475433 100644
--- a/src/mongo/db/commands/plan_cache_commands.h
+++ b/src/mongo/db/commands/plan_cache_commands.h
@@ -57,7 +57,7 @@ public:
      * implement plan cache command functionality.
      */
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const std::string& dbname,
              BSONObj& cmdObj,
              int options,
@@ -86,7 +86,7 @@ public:
      * Should contain just enough logic to invoke run*Command() function
      * in plan_cache.h
      */
-    virtual Status runPlanCacheCommand(OperationContext* txn,
+    virtual Status runPlanCacheCommand(OperationContext* opCtx,
                                        const std::string& ns,
                                        BSONObj& cmdObj,
                                        BSONObjBuilder* bob) = 0;
@@ -94,7 +94,7 @@ public:
     /**
      * Validatess query shape from command object and returns canonical query.
      */
-    static StatusWith<std::unique_ptr<CanonicalQuery>> canonicalize(OperationContext* txn,
+    static StatusWith<std::unique_ptr<CanonicalQuery>> canonicalize(OperationContext* opCtx,
                                                                     const std::string& ns,
                                                                     const BSONObj& cmdObj);
 
@@ -112,7 +112,7 @@ private:
 class PlanCacheListQueryShapes : public PlanCacheCommand {
 public:
     PlanCacheListQueryShapes();
-    virtual Status runPlanCacheCommand(OperationContext* txn,
+    virtual Status runPlanCacheCommand(OperationContext* opCtx,
                                        const std::string& ns,
                                        BSONObj& cmdObj,
                                        BSONObjBuilder* bob);
@@ -138,7 +138,7 @@ public:
 class PlanCacheClear : public PlanCacheCommand {
 public:
     PlanCacheClear();
-    virtual Status runPlanCacheCommand(OperationContext* txn,
+    virtual Status runPlanCacheCommand(OperationContext* opCtx,
                                        const std::string& ns,
                                        BSONObj& cmdObj,
                                        BSONObjBuilder* bob);
@@ -147,7 +147,7 @@ public:
      * Clears collection's plan cache.
      * If query shape is provided, clears plans for that single query shape only.
      */
-    static Status clear(OperationContext* txn,
+    static Status clear(OperationContext* opCtx,
                         PlanCache* planCache,
                         const std::string& ns,
                         const BSONObj& cmdObj);
@@ -167,7 +167,7 @@ public:
 class PlanCacheListPlans : public PlanCacheCommand {
 public:
     PlanCacheListPlans();
-    virtual Status runPlanCacheCommand(OperationContext* txn,
+    virtual Status runPlanCacheCommand(OperationContext* opCtx,
                                        const std::string& ns,
                                        BSONObj& cmdObj,
                                        BSONObjBuilder* bob);
@@ -175,7 +175,7 @@ public:
     /**
      * Displays the cached plans for a query shape.
      */
-    static Status list(OperationContext* txn,
+    static Status list(OperationContext* opCtx,
                        const PlanCache& planCache,
                        const std::string& ns,
                        const BSONObj& cmdObj,
diff --git a/src/mongo/db/commands/plan_cache_commands_test.cpp b/src/mongo/db/commands/plan_cache_commands_test.cpp
index 4975a557443..1ec3611ccdf 100644
--- a/src/mongo/db/commands/plan_cache_commands_test.cpp
+++ b/src/mongo/db/commands/plan_cache_commands_test.cpp
@@ -133,7 +133,7 @@ TEST(PlanCacheCommandsTest, planCacheListQueryShapesEmpty) {
 
 TEST(PlanCacheCommandsTest, planCacheListQueryShapesOneKey) {
     QueryTestServiceContext serviceContext;
-    auto txn = serviceContext.makeOperationContext();
+    auto opCtx = serviceContext.makeOperationContext();
 
     // Create a canonical query
     auto qr = stdx::make_unique<QueryRequest>(nss);
@@ -142,7 +142,7 @@ TEST(PlanCacheCommandsTest, planCacheListQueryShapesOneKey) {
     qr->setProj(fromjson("{_id: 0}"));
     qr->setCollation(fromjson("{locale: 'mock_reverse_string'}"));
     auto statusWithCQ = CanonicalQuery::canonicalize(
-        txn.get(), std::move(qr), ExtensionsCallbackDisallowExtensions());
+        opCtx.get(), std::move(qr), ExtensionsCallbackDisallowExtensions());
     ASSERT_OK(statusWithCQ.getStatus());
     unique_ptr<CanonicalQuery> cq = std::move(statusWithCQ.getValue());
 
@@ -168,13 +168,13 @@ TEST(PlanCacheCommandsTest, planCacheListQueryShapesOneKey) {
 
 TEST(PlanCacheCommandsTest, planCacheClearAllShapes) {
     QueryTestServiceContext serviceContext;
-    auto txn = serviceContext.makeOperationContext();
+    auto opCtx = serviceContext.makeOperationContext();
 
     // Create a canonical query
     auto qr = stdx::make_unique<QueryRequest>(nss);
     qr->setFilter(fromjson("{a: 1}"));
     auto statusWithCQ = CanonicalQuery::canonicalize(
-        txn.get(), std::move(qr), ExtensionsCallbackDisallowExtensions());
+        opCtx.get(), std::move(qr), ExtensionsCallbackDisallowExtensions());
     ASSERT_OK(statusWithCQ.getStatus());
     unique_ptr<CanonicalQuery> cq = std::move(statusWithCQ.getValue());
 
@@ -189,7 +189,7 @@ TEST(PlanCacheCommandsTest, planCacheClearAllShapes) {
     ASSERT_EQUALS(getShapes(planCache).size(), 1U);
 
     // Clear cache and confirm number of keys afterwards.
-    ASSERT_OK(PlanCacheClear::clear(txn.get(), &planCache, nss.ns(), BSONObj()));
+    ASSERT_OK(PlanCacheClear::clear(opCtx.get(), &planCache, nss.ns(), BSONObj()));
     ASSERT_EQUALS(getShapes(planCache).size(), 0U);
 }
 
@@ -202,68 +202,69 @@ TEST(PlanCacheCommandsTest, Canonicalize) {
     // Invalid parameters
     PlanCache planCache;
     QueryTestServiceContext serviceContext;
-    auto txn = serviceContext.makeOperationContext();
+    auto opCtx = serviceContext.makeOperationContext();
 
     // Missing query field
-    ASSERT_NOT_OK(PlanCacheCommand::canonicalize(txn.get(), nss.ns(), fromjson("{}")).getStatus());
+    ASSERT_NOT_OK(
+        PlanCacheCommand::canonicalize(opCtx.get(), nss.ns(), fromjson("{}")).getStatus());
     // Query needs to be an object
     ASSERT_NOT_OK(
-        PlanCacheCommand::canonicalize(txn.get(), nss.ns(), fromjson("{query: 1}")).getStatus());
+        PlanCacheCommand::canonicalize(opCtx.get(), nss.ns(), fromjson("{query: 1}")).getStatus());
     // Sort needs to be an object
     ASSERT_NOT_OK(
-        PlanCacheCommand::canonicalize(txn.get(), nss.ns(), fromjson("{query: {}, sort: 1}"))
+        PlanCacheCommand::canonicalize(opCtx.get(), nss.ns(), fromjson("{query: {}, sort: 1}"))
             .getStatus());
     // Projection needs to be an object.
-    ASSERT_NOT_OK(
-        PlanCacheCommand::canonicalize(txn.get(), nss.ns(), fromjson("{query: {}, projection: 1}"))
-            .getStatus());
+    ASSERT_NOT_OK(PlanCacheCommand::canonicalize(
+                      opCtx.get(), nss.ns(), fromjson("{query: {}, projection: 1}"))
+                      .getStatus());
     // Collation needs to be an object.
     ASSERT_NOT_OK(
-        PlanCacheCommand::canonicalize(txn.get(), nss.ns(), fromjson("{query: {}, collation: 1}"))
+        PlanCacheCommand::canonicalize(opCtx.get(), nss.ns(), fromjson("{query: {}, collation: 1}"))
             .getStatus());
     // Bad query (invalid sort order)
     ASSERT_NOT_OK(
-        PlanCacheCommand::canonicalize(txn.get(), nss.ns(), fromjson("{query: {}, sort: {a: 0}}"))
+        PlanCacheCommand::canonicalize(opCtx.get(), nss.ns(), fromjson("{query: {}, sort: {a: 0}}"))
             .getStatus());
 
     // Valid parameters
     auto statusWithCQ =
-        PlanCacheCommand::canonicalize(txn.get(), nss.ns(), fromjson("{query: {a: 1, b: 1}}"));
+        PlanCacheCommand::canonicalize(opCtx.get(), nss.ns(), fromjson("{query: {a: 1, b: 1}}"));
     ASSERT_OK(statusWithCQ.getStatus());
     unique_ptr<CanonicalQuery> query = std::move(statusWithCQ.getValue());
 
 
     // Equivalent query should generate same key.
     statusWithCQ =
-        PlanCacheCommand::canonicalize(txn.get(), nss.ns(), fromjson("{query: {b: 1, a: 1}}"));
+        PlanCacheCommand::canonicalize(opCtx.get(), nss.ns(), fromjson("{query: {b: 1, a: 1}}"));
     ASSERT_OK(statusWithCQ.getStatus());
     unique_ptr<CanonicalQuery> equivQuery = std::move(statusWithCQ.getValue());
     ASSERT_EQUALS(planCache.computeKey(*query), planCache.computeKey(*equivQuery));
 
     // Sort query should generate different key from unsorted query.
     statusWithCQ = PlanCacheCommand::canonicalize(
-        txn.get(), nss.ns(), fromjson("{query: {a: 1, b: 1}, sort: {a: 1, b: 1}}"));
+        opCtx.get(), nss.ns(), fromjson("{query: {a: 1, b: 1}, sort: {a: 1, b: 1}}"));
     ASSERT_OK(statusWithCQ.getStatus());
     unique_ptr<CanonicalQuery> sortQuery1 = std::move(statusWithCQ.getValue());
     ASSERT_NOT_EQUALS(planCache.computeKey(*query), planCache.computeKey(*sortQuery1));
 
     // Confirm sort arguments are properly delimited (SERVER-17158)
     statusWithCQ = PlanCacheCommand::canonicalize(
-        txn.get(), nss.ns(), fromjson("{query: {a: 1, b: 1}, sort: {aab: 1}}"));
+        opCtx.get(), nss.ns(), fromjson("{query: {a: 1, b: 1}, sort: {aab: 1}}"));
     ASSERT_OK(statusWithCQ.getStatus());
     unique_ptr<CanonicalQuery> sortQuery2 = std::move(statusWithCQ.getValue());
     ASSERT_NOT_EQUALS(planCache.computeKey(*sortQuery1), planCache.computeKey(*sortQuery2));
 
     // Changing order and/or value of predicates should not change key
     statusWithCQ = PlanCacheCommand::canonicalize(
-        txn.get(), nss.ns(), fromjson("{query: {b: 3, a: 3}, sort: {a: 1, b: 1}}"));
+        opCtx.get(), nss.ns(), fromjson("{query: {b: 3, a: 3}, sort: {a: 1, b: 1}}"));
     ASSERT_OK(statusWithCQ.getStatus());
     unique_ptr<CanonicalQuery> sortQuery3 = std::move(statusWithCQ.getValue());
     ASSERT_EQUALS(planCache.computeKey(*sortQuery1), planCache.computeKey(*sortQuery3));
 
     // Projected query should generate different key from unprojected query.
     statusWithCQ = PlanCacheCommand::canonicalize(
-        txn.get(), nss.ns(), fromjson("{query: {a: 1, b: 1}, projection: {_id: 0, a: 1}}"));
+        opCtx.get(), nss.ns(), fromjson("{query: {a: 1, b: 1}, projection: {_id: 0, a: 1}}"));
     ASSERT_OK(statusWithCQ.getStatus());
     unique_ptr<CanonicalQuery> projectionQuery = std::move(statusWithCQ.getValue());
     ASSERT_NOT_EQUALS(planCache.computeKey(*query), planCache.computeKey(*projectionQuery));
@@ -275,47 +276,47 @@ TEST(PlanCacheCommandsTest, Canonicalize) {
 
 TEST(PlanCacheCommandsTest, planCacheClearInvalidParameter) {
     PlanCache planCache;
-    OperationContextNoop txn;
+    OperationContextNoop opCtx;
 
     // Query field type must be BSON object.
-    ASSERT_NOT_OK(PlanCacheClear::clear(&txn, &planCache, nss.ns(), fromjson("{query: 12345}")));
+    ASSERT_NOT_OK(PlanCacheClear::clear(&opCtx, &planCache, nss.ns(), fromjson("{query: 12345}")));
     ASSERT_NOT_OK(
-        PlanCacheClear::clear(&txn, &planCache, nss.ns(), fromjson("{query: /keyisnotregex/}")));
+        PlanCacheClear::clear(&opCtx, &planCache, nss.ns(), fromjson("{query: /keyisnotregex/}")));
     // Query must pass canonicalization.
     ASSERT_NOT_OK(PlanCacheClear::clear(
-        &txn, &planCache, nss.ns(), fromjson("{query: {a: {$no_such_op: 1}}}")));
+        &opCtx, &planCache, nss.ns(), fromjson("{query: {a: {$no_such_op: 1}}}")));
     // Sort present without query is an error.
-    ASSERT_NOT_OK(PlanCacheClear::clear(&txn, &planCache, nss.ns(), fromjson("{sort: {a: 1}}")));
+    ASSERT_NOT_OK(PlanCacheClear::clear(&opCtx, &planCache, nss.ns(), fromjson("{sort: {a: 1}}")));
     // Projection present without query is an error.
     ASSERT_NOT_OK(PlanCacheClear::clear(
-        &txn, &planCache, nss.ns(), fromjson("{projection: {_id: 0, a: 1}}")));
+        &opCtx, &planCache, nss.ns(), fromjson("{projection: {_id: 0, a: 1}}")));
     // Collation present without query is an error.
     ASSERT_NOT_OK(PlanCacheClear::clear(
-        &txn, &planCache, nss.ns(), fromjson("{collation: {locale: 'en_US'}}")));
+        &opCtx, &planCache, nss.ns(), fromjson("{collation: {locale: 'en_US'}}")));
 }
 
 TEST(PlanCacheCommandsTest, planCacheClearUnknownKey) {
     PlanCache planCache;
-    OperationContextNoop txn;
+    OperationContextNoop opCtx;
 
-    ASSERT_OK(PlanCacheClear::clear(&txn, &planCache, nss.ns(), fromjson("{query: {a: 1}}")));
+    ASSERT_OK(PlanCacheClear::clear(&opCtx, &planCache, nss.ns(), fromjson("{query: {a: 1}}")));
 }
 
 TEST(PlanCacheCommandsTest, planCacheClearOneKey) {
     QueryTestServiceContext serviceContext;
-    auto txn = serviceContext.makeOperationContext();
+    auto opCtx = serviceContext.makeOperationContext();
 
     // Create 2 canonical queries.
     auto qrA = stdx::make_unique<QueryRequest>(nss);
     qrA->setFilter(fromjson("{a: 1}"));
     auto statusWithCQA = CanonicalQuery::canonicalize(
-        txn.get(), std::move(qrA), ExtensionsCallbackDisallowExtensions());
+        opCtx.get(), std::move(qrA), ExtensionsCallbackDisallowExtensions());
     ASSERT_OK(statusWithCQA.getStatus());
     auto qrB = stdx::make_unique<QueryRequest>(nss);
     qrB->setFilter(fromjson("{b: 1}"));
     unique_ptr<CanonicalQuery> cqA = std::move(statusWithCQA.getValue());
     auto statusWithCQB = CanonicalQuery::canonicalize(
-        txn.get(), std::move(qrB), ExtensionsCallbackDisallowExtensions());
+        opCtx.get(), std::move(qrB), ExtensionsCallbackDisallowExtensions());
     ASSERT_OK(statusWithCQB.getStatus());
     unique_ptr<CanonicalQuery> cqB = std::move(statusWithCQB.getValue());
 
@@ -350,7 +351,7 @@ TEST(PlanCacheCommandsTest, planCacheClearOneKey) {
     BSONObjBuilder bob;
 
     ASSERT_OK(PlanCacheClear::clear(
-        txn.get(), &planCache, nss.ns(), BSON("query" << cqB->getQueryObj())));
+        opCtx.get(), &planCache, nss.ns(), BSON("query" << cqB->getQueryObj())));
     vector<BSONObj> shapesAfter = getShapes(planCache);
     ASSERT_EQUALS(shapesAfter.size(), 1U);
     ASSERT_BSONOBJ_EQ(shapesAfter[0], shapeA);
@@ -358,20 +359,20 @@ TEST(PlanCacheCommandsTest, planCacheClearOneKey) {
 
 TEST(PlanCacheCommandsTest, planCacheClearOneKeyCollation) {
     QueryTestServiceContext serviceContext;
-    auto txn = serviceContext.makeOperationContext();
+    auto opCtx = serviceContext.makeOperationContext();
 
     // Create 2 canonical queries, one with collation.
     auto qr = stdx::make_unique<QueryRequest>(nss);
     qr->setFilter(fromjson("{a: 'foo'}"));
     auto statusWithCQ = CanonicalQuery::canonicalize(
-        txn.get(), std::move(qr), ExtensionsCallbackDisallowExtensions());
+        opCtx.get(), std::move(qr), ExtensionsCallbackDisallowExtensions());
     ASSERT_OK(statusWithCQ.getStatus());
     unique_ptr<CanonicalQuery> cq = std::move(statusWithCQ.getValue());
     auto qrCollation = stdx::make_unique<QueryRequest>(nss);
     qrCollation->setFilter(fromjson("{a: 'foo'}"));
     qrCollation->setCollation(fromjson("{locale: 'mock_reverse_string'}"));
     auto statusWithCQCollation = CanonicalQuery::canonicalize(
-        txn.get(), std::move(qrCollation), ExtensionsCallbackDisallowExtensions());
+        opCtx.get(), std::move(qrCollation), ExtensionsCallbackDisallowExtensions());
     ASSERT_OK(statusWithCQCollation.getStatus());
     unique_ptr<CanonicalQuery> cqCollation = std::move(statusWithCQCollation.getValue());
 
@@ -412,7 +413,7 @@ TEST(PlanCacheCommandsTest, planCacheClearOneKeyCollation) {
     // Drop query with collation from cache. Make other query is still in cache afterwards.
     BSONObjBuilder bob;
 
-    ASSERT_OK(PlanCacheClear::clear(txn.get(), &planCache, nss.ns(), shapeWithCollation));
+    ASSERT_OK(PlanCacheClear::clear(opCtx.get(), &planCache, nss.ns(), shapeWithCollation));
     vector<BSONObj> shapesAfter = getShapes(planCache);
     ASSERT_EQUALS(shapesAfter.size(), 1U);
     ASSERT_BSONOBJ_EQ(shapesAfter[0], shape);
@@ -464,7 +465,7 @@ vector<BSONObj> getPlans(const PlanCache& planCache,
                          const BSONObj& projection,
                          const BSONObj& collation) {
     QueryTestServiceContext serviceContext;
-    auto txn = serviceContext.makeOperationContext();
+    auto opCtx = serviceContext.makeOperationContext();
 
     BSONObjBuilder bob;
     BSONObjBuilder cmdObjBuilder;
@@ -475,7 +476,7 @@ vector<BSONObj> getPlans(const PlanCache& planCache,
         cmdObjBuilder.append("collation", collation);
     }
     BSONObj cmdObj = cmdObjBuilder.obj();
-    ASSERT_OK(PlanCacheListPlans::list(txn.get(), planCache, nss.ns(), cmdObj, &bob));
+    ASSERT_OK(PlanCacheListPlans::list(opCtx.get(), planCache, nss.ns(), cmdObj, &bob));
     BSONObj resultObj = bob.obj();
     BSONElement plansElt = resultObj.getField("plans");
     ASSERT_EQUALS(plansElt.type(), mongo::Array);
@@ -489,36 +490,36 @@ vector<BSONObj> getPlans(const PlanCache& planCache,
 TEST(PlanCacheCommandsTest, planCacheListPlansInvalidParameter) {
     PlanCache planCache;
     BSONObjBuilder ignored;
-    OperationContextNoop txn;
+    OperationContextNoop opCtx;
 
     // Missing query field is not ok.
-    ASSERT_NOT_OK(PlanCacheListPlans::list(&txn, planCache, nss.ns(), BSONObj(), &ignored));
+    ASSERT_NOT_OK(PlanCacheListPlans::list(&opCtx, planCache, nss.ns(), BSONObj(), &ignored));
     // Query field type must be BSON object.
-    ASSERT_NOT_OK(
-        PlanCacheListPlans::list(&txn, planCache, nss.ns(), fromjson("{query: 12345}"), &ignored));
     ASSERT_NOT_OK(PlanCacheListPlans::list(
-        &txn, planCache, nss.ns(), fromjson("{query: /keyisnotregex/}"), &ignored));
+        &opCtx, planCache, nss.ns(), fromjson("{query: 12345}"), &ignored));
+    ASSERT_NOT_OK(PlanCacheListPlans::list(
+        &opCtx, planCache, nss.ns(), fromjson("{query: /keyisnotregex/}"), &ignored));
 }
 
 TEST(PlanCacheCommandsTest, planCacheListPlansUnknownKey) {
     // Leave the plan cache empty.
     PlanCache planCache;
-    OperationContextNoop txn;
+    OperationContextNoop opCtx;
 
     BSONObjBuilder ignored;
-    ASSERT_OK(
-        PlanCacheListPlans::list(&txn, planCache, nss.ns(), fromjson("{query: {a: 1}}"), &ignored));
+    ASSERT_OK(PlanCacheListPlans::list(
+        &opCtx, planCache, nss.ns(), fromjson("{query: {a: 1}}"), &ignored));
 }
 
 TEST(PlanCacheCommandsTest, planCacheListPlansOnlyOneSolutionTrue) {
     QueryTestServiceContext serviceContext;
-    auto txn = serviceContext.makeOperationContext();
+    auto opCtx = serviceContext.makeOperationContext();
 
     // Create a canonical query
     auto qr = stdx::make_unique<QueryRequest>(nss);
     qr->setFilter(fromjson("{a: 1}"));
     auto statusWithCQ = CanonicalQuery::canonicalize(
-        txn.get(), std::move(qr), ExtensionsCallbackDisallowExtensions());
+        opCtx.get(), std::move(qr), ExtensionsCallbackDisallowExtensions());
     ASSERT_OK(statusWithCQ.getStatus());
     unique_ptr<CanonicalQuery> cq = std::move(statusWithCQ.getValue());
 
@@ -540,13 +541,13 @@ TEST(PlanCacheCommandsTest, planCacheListPlansOnlyOneSolutionTrue) {
 
 TEST(PlanCacheCommandsTest, planCacheListPlansOnlyOneSolutionFalse) {
     QueryTestServiceContext serviceContext;
-    auto txn = serviceContext.makeOperationContext();
+    auto opCtx = serviceContext.makeOperationContext();
 
     // Create a canonical query
     auto qr = stdx::make_unique<QueryRequest>(nss);
     qr->setFilter(fromjson("{a: 1}"));
     auto statusWithCQ = CanonicalQuery::canonicalize(
-        txn.get(), std::move(qr), ExtensionsCallbackDisallowExtensions());
+        opCtx.get(), std::move(qr), ExtensionsCallbackDisallowExtensions());
     ASSERT_OK(statusWithCQ.getStatus());
     unique_ptr<CanonicalQuery> cq = std::move(statusWithCQ.getValue());
 
@@ -571,20 +572,20 @@ TEST(PlanCacheCommandsTest, planCacheListPlansOnlyOneSolutionFalse) {
 
 TEST(PlanCacheCommandsTest, planCacheListPlansCollation) {
     QueryTestServiceContext serviceContext;
-    auto txn = serviceContext.makeOperationContext();
+    auto opCtx = serviceContext.makeOperationContext();
 
     // Create 2 canonical queries, one with collation.
     auto qr = stdx::make_unique<QueryRequest>(nss);
     qr->setFilter(fromjson("{a: 'foo'}"));
     auto statusWithCQ = CanonicalQuery::canonicalize(
-        txn.get(), std::move(qr), ExtensionsCallbackDisallowExtensions());
+        opCtx.get(), std::move(qr), ExtensionsCallbackDisallowExtensions());
     ASSERT_OK(statusWithCQ.getStatus());
     unique_ptr<CanonicalQuery> cq = std::move(statusWithCQ.getValue());
     auto qrCollation = stdx::make_unique<QueryRequest>(nss);
     qrCollation->setFilter(fromjson("{a: 'foo'}"));
     qrCollation->setCollation(fromjson("{locale: 'mock_reverse_string'}"));
     auto statusWithCQCollation = CanonicalQuery::canonicalize(
-        txn.get(), std::move(qrCollation), ExtensionsCallbackDisallowExtensions());
+        opCtx.get(), std::move(qrCollation), ExtensionsCallbackDisallowExtensions());
     ASSERT_OK(statusWithCQCollation.getStatus());
     unique_ptr<CanonicalQuery> cqCollation = std::move(statusWithCQCollation.getValue());
 
diff --git a/src/mongo/db/commands/rename_collection_cmd.cpp b/src/mongo/db/commands/rename_collection_cmd.cpp
index 99f5617cf94..6aaa3b5f744 100644
--- a/src/mongo/db/commands/rename_collection_cmd.cpp
+++ b/src/mongo/db/commands/rename_collection_cmd.cpp
@@ -77,15 +77,15 @@ public:
         help << " example: { renameCollection: foo.a, to: bar.b }";
     }
 
-    static void dropCollection(OperationContext* txn, Database* db, StringData collName) {
-        WriteUnitOfWork wunit(txn);
-        if (db->dropCollection(txn, collName).isOK()) {
+    static void dropCollection(OperationContext* opCtx, Database* db, StringData collName) {
+        WriteUnitOfWork wunit(opCtx);
+        if (db->dropCollection(opCtx, collName).isOK()) {
             // ignoring failure case
             wunit.commit();
         }
     }
 
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const string& dbname,
                      BSONObj& cmdObj,
                      int,
@@ -146,7 +146,7 @@ public:
         }
 
         return appendCommandStatus(result,
-                                   renameCollection(txn,
+                                   renameCollection(opCtx,
                                                     source,
                                                     target,
                                                     cmdObj["dropTarget"].trueValue(),
diff --git a/src/mongo/db/commands/repair_cursor.cpp b/src/mongo/db/commands/repair_cursor.cpp
index 4e34e0bbb0f..b5d7c2fde6f 100644
--- a/src/mongo/db/commands/repair_cursor.cpp
+++ b/src/mongo/db/commands/repair_cursor.cpp
@@ -67,7 +67,7 @@ public:
         return Status(ErrorCodes::Unauthorized, "Unauthorized");
     }
 
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const string& dbname,
                      BSONObj& cmdObj,
                      int options,
@@ -75,7 +75,7 @@ public:
                      BSONObjBuilder& result) {
         NamespaceString ns(parseNs(dbname, cmdObj));
 
-        AutoGetCollectionForRead ctx(txn, ns);
+        AutoGetCollectionForRead ctx(opCtx, ns);
 
         Collection* collection = ctx.getCollection();
         if (!collection) {
@@ -83,7 +83,7 @@ public:
                 result, Status(ErrorCodes::NamespaceNotFound, "ns does not exist: " + ns.ns()));
         }
 
-        auto cursor = collection->getRecordStore()->getCursorForRepair(txn);
+        auto cursor = collection->getRecordStore()->getCursorForRepair(opCtx);
         if (!cursor) {
             return appendCommandStatus(
                 result, Status(ErrorCodes::CommandNotSupported, "repair iterator not supported"));
@@ -91,11 +91,11 @@ public:
 
         std::unique_ptr<WorkingSet> ws(new WorkingSet());
         std::unique_ptr<MultiIteratorStage> stage(
-            new MultiIteratorStage(txn, ws.get(), collection));
+            new MultiIteratorStage(opCtx, ws.get(), collection));
         stage->addIterator(std::move(cursor));
 
         auto statusWithPlanExecutor = PlanExecutor::make(
-            txn, std::move(ws), std::move(stage), collection, PlanExecutor::YIELD_AUTO);
+            opCtx, std::move(ws), std::move(stage), collection, PlanExecutor::YIELD_AUTO);
         invariant(statusWithPlanExecutor.isOK());
         std::unique_ptr<PlanExecutor> exec = std::move(statusWithPlanExecutor.getValue());
 
@@ -109,7 +109,7 @@ public:
         auto pinnedCursor = collection->getCursorManager()->registerCursor(
             {exec.release(),
              ns.ns(),
-             txn->recoveryUnit()->isReadingFromMajorityCommittedSnapshot()});
+             opCtx->recoveryUnit()->isReadingFromMajorityCommittedSnapshot()});
 
         appendCursorResponseObject(
             pinnedCursor.getCursor()->cursorid(), ns.ns(), BSONArray(), &result);
diff --git a/src/mongo/db/commands/server_status.cpp b/src/mongo/db/commands/server_status.cpp
index 67716cf7a14..fd429ed21b1 100644
--- a/src/mongo/db/commands/server_status.cpp
+++ b/src/mongo/db/commands/server_status.cpp
@@ -85,7 +85,7 @@ public:
         actions.addAction(ActionType::serverStatus);
         out->push_back(Privilege(ResourcePattern::forClusterResource(), actions));
     }
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int,
@@ -93,7 +93,7 @@ public:
              BSONObjBuilder& result) {
         _runCalled = true;
 
-        const auto service = txn->getServiceContext();
+        const auto service = opCtx->getServiceContext();
         const auto clock = service->getFastClockSource();
         const auto runStart = clock->now();
         BSONObjBuilder timeBuilder(256);
@@ -135,7 +135,7 @@ public:
                 continue;
             }
 
-            section->appendSection(txn, elem, &result);
+            section->appendSection(opCtx, elem, &result);
             timeBuilder.appendNumber(
                 static_cast<string>(str::stream() << "after " << section->getSectionName()),
                 durationCount<Milliseconds>(clock->now() - runStart));
@@ -201,7 +201,7 @@ OpCounterServerStatusSection::OpCounterServerStatusSection(const string& section
                                                            OpCounters* counters)
     : ServerStatusSection(sectionName), _counters(counters) {}
 
-BSONObj OpCounterServerStatusSection::generateSection(OperationContext* txn,
+BSONObj OpCounterServerStatusSection::generateSection(OperationContext* opCtx,
                                                       const BSONElement& configElement) const {
     return _counters->getObj();
 }
@@ -220,9 +220,9 @@ public:
         return true;
     }
 
-    BSONObj generateSection(OperationContext* txn, const BSONElement& configElement) const {
+    BSONObj generateSection(OperationContext* opCtx, const BSONElement& configElement) const {
         BSONObjBuilder bb;
-        auto stats = txn->getServiceContext()->getTransportLayer()->sessionStats();
+        auto stats = opCtx->getServiceContext()->getTransportLayer()->sessionStats();
         bb.append("current", static_cast<int>(stats.numOpenSessions));
         bb.append("available", static_cast<int>(stats.numAvailableSessions));
         bb.append("totalCreated", static_cast<int>(stats.numCreatedSessions));
@@ -238,7 +238,7 @@ public:
         return true;
     }
 
-    BSONObj generateSection(OperationContext* txn, const BSONElement& configElement) const {
+    BSONObj generateSection(OperationContext* opCtx, const BSONElement& configElement) const {
         BSONObjBuilder bb;
 
         bb.append("note", "fields vary by platform");
@@ -258,7 +258,7 @@ public:
         return true;
     }
 
-    BSONObj generateSection(OperationContext* txn, const BSONElement& configElement) const {
+    BSONObj generateSection(OperationContext* opCtx, const BSONElement& configElement) const {
         BSONObjBuilder asserts;
         asserts.append("regular", assertionCount.regular);
         asserts.append("warning", assertionCount.warning);
@@ -278,7 +278,7 @@ public:
         return true;
     }
 
-    BSONObj generateSection(OperationContext* txn, const BSONElement& configElement) const {
+    BSONObj generateSection(OperationContext* opCtx, const BSONElement& configElement) const {
         BSONObjBuilder b;
         networkCounter.append(b);
         appendMessageCompressionStats(&b);
@@ -295,7 +295,7 @@ public:
         return true;
     }
 
-    BSONObj generateSection(OperationContext* txn, const BSONElement& configElement) const {
+    BSONObj generateSection(OperationContext* opCtx, const BSONElement& configElement) const {
         BSONObj result;
         if (getSSLManager()) {
             result = getSSLManager()->getSSLConfiguration().getServerStatusBSON();
@@ -334,7 +334,7 @@ public:
         return false;
     }
 
-    void appendSection(OperationContext* txn,
+    void appendSection(OperationContext* opCtx,
                        const BSONElement& configElement,
                        BSONObjBuilder* out) const override {
         out->append(
diff --git a/src/mongo/db/commands/server_status.h b/src/mongo/db/commands/server_status.h
index b017688acf2..506c1428629 100644
--- a/src/mongo/db/commands/server_status.h
+++ b/src/mongo/db/commands/server_status.h
@@ -80,7 +80,8 @@ public:
      * @param configElement the element from the actual command related to this section
      *                      so if the section is 'foo', this is cmdObj['foo']
      */
-    virtual BSONObj generateSection(OperationContext* txn, const BSONElement& configElement) const {
+    virtual BSONObj generateSection(OperationContext* opCtx,
+                                    const BSONElement& configElement) const {
         return BSONObj{};
     };
 
@@ -94,10 +95,10 @@ public:
      * If you are doing something a bit more complicated, you can implement this and have
      * full control over what gets included in the command result.
      */
-    virtual void appendSection(OperationContext* txn,
+    virtual void appendSection(OperationContext* opCtx,
                                const BSONElement& configElement,
                                BSONObjBuilder* result) const {
-        const auto ret = generateSection(txn, configElement);
+        const auto ret = generateSection(opCtx, configElement);
         if (ret.isEmpty())
             return;
         result->append(getSectionName(), ret);
@@ -114,7 +115,8 @@ public:
         return true;
     }
 
-    virtual BSONObj generateSection(OperationContext* txn, const BSONElement& configElement) const;
+    virtual BSONObj generateSection(OperationContext* opCtx,
+                                    const BSONElement& configElement) const;
 
 private:
     const OpCounters* _counters;
diff --git a/src/mongo/db/commands/set_feature_compatibility_version_command.cpp b/src/mongo/db/commands/set_feature_compatibility_version_command.cpp
index 4d6c7f9867d..6e173143efc 100644
--- a/src/mongo/db/commands/set_feature_compatibility_version_command.cpp
+++ b/src/mongo/db/commands/set_feature_compatibility_version_command.cpp
@@ -81,7 +81,7 @@ public:
         return Status::OK();
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const std::string& dbname,
              BSONObj& cmdObj,
              int options,
@@ -90,7 +90,7 @@ public:
         const auto version = uassertStatusOK(
             FeatureCompatibilityVersionCommandParser::extractVersionFromCommand(getName(), cmdObj));
 
-        FeatureCompatibilityVersion::set(txn, version);
+        FeatureCompatibilityVersion::set(opCtx, version);
 
         return true;
     }
diff --git a/src/mongo/db/commands/snapshot_management.cpp b/src/mongo/db/commands/snapshot_management.cpp
index 5c215c4c6f4..8ab963eb71e 100644
--- a/src/mongo/db/commands/snapshot_management.cpp
+++ b/src/mongo/db/commands/snapshot_management.cpp
@@ -63,7 +63,7 @@ public:
         h << "Creates a new named snapshot";
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const std::string& dbname,
              BSONObj& cmdObj,
              int,
@@ -75,14 +75,15 @@ public:
             return appendCommandStatus(result, {ErrorCodes::CommandNotSupported, ""});
         }
 
-        ScopedTransaction st(txn, MODE_IX);
-        Lock::GlobalLock lk(txn->lockState(), MODE_IX, UINT_MAX);
+        ScopedTransaction st(opCtx, MODE_IX);
+        Lock::GlobalLock lk(opCtx->lockState(), MODE_IX, UINT_MAX);
 
-        auto status = snapshotManager->prepareForCreateSnapshot(txn);
+        auto status = snapshotManager->prepareForCreateSnapshot(opCtx);
         if (status.isOK()) {
-            const auto name = repl::ReplicationCoordinator::get(txn)->reserveSnapshotName(nullptr);
+            const auto name =
+                repl::ReplicationCoordinator::get(opCtx)->reserveSnapshotName(nullptr);
             result.append("name", static_cast<long long>(name.asU64()));
-            status = snapshotManager->createSnapshot(txn, name);
+            status = snapshotManager->createSnapshot(opCtx, name);
         }
         return appendCommandStatus(result, status);
     }
@@ -113,7 +114,7 @@ public:
         h << "Sets the snapshot for {readConcern: {level: 'majority'}}";
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const std::string& dbname,
              BSONObj& cmdObj,
              int,
@@ -125,8 +126,8 @@ public:
             return appendCommandStatus(result, {ErrorCodes::CommandNotSupported, ""});
         }
 
-        ScopedTransaction st(txn, MODE_IX);
-        Lock::GlobalLock lk(txn->lockState(), MODE_IX, UINT_MAX);
+        ScopedTransaction st(opCtx, MODE_IX);
+        Lock::GlobalLock lk(opCtx->lockState(), MODE_IX, UINT_MAX);
         auto name = SnapshotName(cmdObj.firstElement().Long());
         snapshotManager->setCommittedSnapshot(name);
         return true;
diff --git a/src/mongo/db/commands/test_commands.cpp b/src/mongo/db/commands/test_commands.cpp
index 560e6496688..34bc757d554 100644
--- a/src/mongo/db/commands/test_commands.cpp
+++ b/src/mongo/db/commands/test_commands.cpp
@@ -75,7 +75,7 @@ public:
     virtual void help(stringstream& help) const {
         help << "internal. for testing only.";
     }
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const string& dbname,
                      BSONObj& cmdObj,
                      int,
@@ -85,23 +85,23 @@ public:
         log() << "test only command godinsert invoked coll:" << nss.coll();
         BSONObj obj = cmdObj["obj"].embeddedObjectUserCheck();
 
-        ScopedTransaction transaction(txn, MODE_IX);
-        Lock::DBLock lk(txn->lockState(), dbname, MODE_X);
-        OldClientContext ctx(txn, nss.ns());
+        ScopedTransaction transaction(opCtx, MODE_IX);
+        Lock::DBLock lk(opCtx->lockState(), dbname, MODE_X);
+        OldClientContext ctx(opCtx, nss.ns());
         Database* db = ctx.db();
 
-        WriteUnitOfWork wunit(txn);
-        UnreplicatedWritesBlock unreplicatedWritesBlock(txn);
+        WriteUnitOfWork wunit(opCtx);
+        UnreplicatedWritesBlock unreplicatedWritesBlock(opCtx);
         Collection* collection = db->getCollection(nss);
         if (!collection) {
-            collection = db->createCollection(txn, nss.ns());
+            collection = db->createCollection(opCtx, nss.ns());
             if (!collection) {
                 errmsg = "could not create collection";
                 return false;
             }
         }
         OpDebug* const nullOpDebug = nullptr;
-        Status status = collection->insertDocument(txn, obj, nullOpDebug, false);
+        Status status = collection->insertDocument(opCtx, obj, nullOpDebug, false);
         if (status.isOK()) {
             wunit.commit();
         }
@@ -140,20 +140,20 @@ public:
                                        const BSONObj& cmdObj,
                                        std::vector<Privilege>* out) {}
 
-    void _sleepInReadLock(mongo::OperationContext* txn, long long millis) {
-        ScopedTransaction transaction(txn, MODE_S);
-        Lock::GlobalRead lk(txn->lockState());
+    void _sleepInReadLock(mongo::OperationContext* opCtx, long long millis) {
+        ScopedTransaction transaction(opCtx, MODE_S);
+        Lock::GlobalRead lk(opCtx->lockState());
         sleepmillis(millis);
     }
 
-    void _sleepInWriteLock(mongo::OperationContext* txn, long long millis) {
-        ScopedTransaction transaction(txn, MODE_X);
-        Lock::GlobalWrite lk(txn->lockState());
+    void _sleepInWriteLock(mongo::OperationContext* opCtx, long long millis) {
+        ScopedTransaction transaction(opCtx, MODE_X);
+        Lock::GlobalWrite lk(opCtx->lockState());
         sleepmillis(millis);
     }
 
     CmdSleep() : Command("sleep") {}
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& ns,
              BSONObj& cmdObj,
              int,
@@ -178,9 +178,9 @@ public:
         if (!cmdObj["lock"]) {
             // Legacy implementation
             if (cmdObj.getBoolField("w")) {
-                _sleepInWriteLock(txn, millis);
+                _sleepInWriteLock(opCtx, millis);
             } else {
-                _sleepInReadLock(txn, millis);
+                _sleepInReadLock(opCtx, millis);
             }
         } else {
             uassert(34346, "Only one of 'w' and 'lock' may be set.", !cmdObj["w"]);
@@ -189,15 +189,15 @@ public:
             if (lock == "none") {
                 sleepmillis(millis);
             } else if (lock == "w") {
-                _sleepInWriteLock(txn, millis);
+                _sleepInWriteLock(opCtx, millis);
             } else {
                 uassert(34347, "'lock' must be one of 'r', 'w', 'none'.", lock == "r");
-                _sleepInReadLock(txn, millis);
+                _sleepInReadLock(opCtx, millis);
             }
         }
 
         // Interrupt point for testing (e.g. maxTimeMS).
-        txn->checkForInterrupt();
+        opCtx->checkForInterrupt();
 
         return true;
     }
@@ -217,7 +217,7 @@ public:
     virtual void addRequiredPrivileges(const std::string& dbname,
                                        const BSONObj& cmdObj,
                                        std::vector<Privilege>* out) {}
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const string& dbname,
                      BSONObj& cmdObj,
                      int,
@@ -232,11 +232,11 @@ public:
                                        {ErrorCodes::BadValue, "n must be a positive integer"});
         }
 
-        OldClientWriteContext ctx(txn, fullNs.ns());
+        OldClientWriteContext ctx(opCtx, fullNs.ns());
         Collection* collection = ctx.getCollection();
 
         if (!collection) {
-            if (ctx.db()->getViewCatalog()->lookup(txn, fullNs.ns())) {
+            if (ctx.db()->getViewCatalog()->lookup(opCtx, fullNs.ns())) {
                 return appendCommandStatus(
                     result,
                     {ErrorCodes::CommandNotSupportedOnView,
@@ -259,7 +259,7 @@ public:
             // We will remove 'n' documents, so start truncating from the (n + 1)th document to the
             // end.
             std::unique_ptr<PlanExecutor> exec(
-                InternalPlanner::collectionScan(txn,
+                InternalPlanner::collectionScan(opCtx,
                                                 fullNs.ns(),
                                                 collection,
                                                 PlanExecutor::YIELD_MANUAL,
@@ -277,7 +277,7 @@ public:
             }
         }
 
-        collection->cappedTruncateAfter(txn, end, inc);
+        collection->cappedTruncateAfter(opCtx, end, inc);
 
         return true;
     }
@@ -298,7 +298,7 @@ public:
                                        const BSONObj& cmdObj,
                                        std::vector<Privilege>* out) {}
 
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const string& dbname,
                      BSONObj& cmdObj,
                      int,
@@ -306,7 +306,7 @@ public:
                      BSONObjBuilder& result) {
         const NamespaceString nss = parseNsCollectionRequired(dbname, cmdObj);
 
-        return appendCommandStatus(result, emptyCapped(txn, nss));
+        return appendCommandStatus(result, emptyCapped(opCtx, nss));
     }
 };
 
diff --git a/src/mongo/db/commands/top_command.cpp b/src/mongo/db/commands/top_command.cpp
index 6f236de90da..80ef9171efd 100644
--- a/src/mongo/db/commands/top_command.cpp
+++ b/src/mongo/db/commands/top_command.cpp
@@ -65,7 +65,7 @@ public:
         actions.addAction(ActionType::top);
         out->push_back(Privilege(ResourcePattern::forClusterResource(), actions));
     }
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const std::string& db,
                      BSONObj& cmdObj,
                      int options,
@@ -74,7 +74,7 @@ public:
         {
             BSONObjBuilder b(result.subobjStart("totals"));
             b.append("note", "all times in microseconds");
-            Top::get(txn->getClient()->getServiceContext()).append(b);
+            Top::get(opCtx->getClient()->getServiceContext()).append(b);
             b.done();
         }
         return true;
diff --git a/src/mongo/db/commands/touch.cpp b/src/mongo/db/commands/touch.cpp
index a1fe53e84d8..1f28da9e3fc 100644
--- a/src/mongo/db/commands/touch.cpp
+++ b/src/mongo/db/commands/touch.cpp
@@ -82,7 +82,7 @@ public:
     }
     TouchCmd() : Command("touch") {}
 
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const string& dbname,
                      BSONObj& cmdObj,
                      int,
@@ -102,7 +102,7 @@ public:
             return false;
         }
 
-        AutoGetCollectionForRead context(txn, nss);
+        AutoGetCollectionForRead context(opCtx, nss);
 
         Collection* collection = context.getCollection();
         if (!collection) {
@@ -111,7 +111,7 @@ public:
         }
 
         return appendCommandStatus(result,
-                                   collection->touch(txn, touch_data, touch_indexes, &result));
+                                   collection->touch(opCtx, touch_data, touch_indexes, &result));
     }
 };
 static TouchCmd touchCmd;
diff --git a/src/mongo/db/commands/user_management_commands.cpp b/src/mongo/db/commands/user_management_commands.cpp
index 7d14e2f1416..b6a55727c80 100644
--- a/src/mongo/db/commands/user_management_commands.cpp
+++ b/src/mongo/db/commands/user_management_commands.cpp
@@ -135,13 +135,13 @@ Status privilegeVectorToBSONArray(const PrivilegeVector& privileges, BSONArray*
 /**
  * Used to get all current roles of the user identified by 'userName'.
  */
-Status getCurrentUserRoles(OperationContext* txn,
+Status getCurrentUserRoles(OperationContext* opCtx,
                            AuthorizationManager* authzManager,
                            const UserName& userName,
                            unordered_set<RoleName>* roles) {
     User* user;
     authzManager->invalidateUserByName(userName);  // Need to make sure cache entry is up to date
-    Status status = authzManager->acquireUser(txn, userName, &user);
+    Status status = authzManager->acquireUser(opCtx, userName, &user);
     if (!status.isOK()) {
         return status;
     }
@@ -159,7 +159,7 @@ Status getCurrentUserRoles(OperationContext* txn,
  * same database as the role it is being added to (or that the role being added to is from the
  * "admin" database.
  */
-Status checkOkayToGrantRolesToRole(OperationContext* txn,
+Status checkOkayToGrantRolesToRole(OperationContext* opCtx,
                                    const RoleName& role,
                                    const std::vector<RoleName> rolesToAdd,
                                    AuthorizationManager* authzManager) {
@@ -180,8 +180,8 @@ Status checkOkayToGrantRolesToRole(OperationContext* txn,
         }
 
         BSONObj roleToAddDoc;
-        Status status =
-            authzManager->getRoleDescription(txn, roleToAdd, PrivilegeFormat::kOmit, &roleToAddDoc);
+        Status status = authzManager->getRoleDescription(
+            opCtx, roleToAdd, PrivilegeFormat::kOmit, &roleToAddDoc);
         if (status == ErrorCodes::RoleNotFound) {
             return Status(ErrorCodes::RoleNotFound,
                           "Cannot grant nonexistent role " + roleToAdd.toString());
@@ -242,13 +242,13 @@ void appendBSONObjToBSONArrayBuilder(BSONArrayBuilder* array, const BSONObj& obj
  * Should only be called on collections with authorization documents in them
  * (ie admin.system.users and admin.system.roles).
  */
-Status queryAuthzDocument(OperationContext* txn,
+Status queryAuthzDocument(OperationContext* opCtx,
                           const NamespaceString& collectionName,
                           const BSONObj& query,
                           const BSONObj& projection,
                           const stdx::function<void(const BSONObj&)>& resultProcessor) {
     try {
-        DBDirectClient client(txn);
+        DBDirectClient client(opCtx);
         client.query(resultProcessor, collectionName.ns(), query, &projection);
         return Status::OK();
     } catch (const DBException& e) {
@@ -263,11 +263,11 @@ Status queryAuthzDocument(OperationContext* txn,
  * Should only be called on collections with authorization documents in them
  * (ie admin.system.users and admin.system.roles).
  */
-Status insertAuthzDocument(OperationContext* txn,
+Status insertAuthzDocument(OperationContext* opCtx,
                            const NamespaceString& collectionName,
                            const BSONObj& document) {
     try {
-        DBDirectClient client(txn);
+        DBDirectClient client(opCtx);
 
         BatchedInsertRequest req;
         req.setNS(collectionName);
@@ -293,7 +293,7 @@ Status insertAuthzDocument(OperationContext* txn,
  * Should only be called on collections with authorization documents in them
  * (ie admin.system.users and admin.system.roles).
  */
-Status updateAuthzDocuments(OperationContext* txn,
+Status updateAuthzDocuments(OperationContext* opCtx,
                             const NamespaceString& collectionName,
                             const BSONObj& query,
                             const BSONObj& updatePattern,
@@ -301,7 +301,7 @@ Status updateAuthzDocuments(OperationContext* txn,
                             bool multi,
                             long long* nMatched) {
     try {
-        DBDirectClient client(txn);
+        DBDirectClient client(opCtx);
 
         auto doc = stdx::make_unique<BatchedUpdateDocument>();
         doc->setQuery(query);
@@ -342,14 +342,14 @@ Status updateAuthzDocuments(OperationContext* txn,
  * Should only be called on collections with authorization documents in them
  * (ie admin.system.users and admin.system.roles).
  */
-Status updateOneAuthzDocument(OperationContext* txn,
+Status updateOneAuthzDocument(OperationContext* opCtx,
                               const NamespaceString& collectionName,
                               const BSONObj& query,
                               const BSONObj& updatePattern,
                               bool upsert) {
     long long nMatched;
     Status status =
-        updateAuthzDocuments(txn, collectionName, query, updatePattern, upsert, false, &nMatched);
+        updateAuthzDocuments(opCtx, collectionName, query, updatePattern, upsert, false, &nMatched);
     if (!status.isOK()) {
         return status;
     }
@@ -366,12 +366,12 @@ Status updateOneAuthzDocument(OperationContext* txn,
  * Should only be called on collections with authorization documents in them
  * (ie admin.system.users and admin.system.roles).
  */
-Status removeAuthzDocuments(OperationContext* txn,
+Status removeAuthzDocuments(OperationContext* opCtx,
                             const NamespaceString& collectionName,
                             const BSONObj& query,
                             long long* numRemoved) {
     try {
-        DBDirectClient client(txn);
+        DBDirectClient client(opCtx);
 
         auto doc = stdx::make_unique<BatchedDeleteDocument>();
         doc->setQuery(query);
@@ -401,9 +401,9 @@ Status removeAuthzDocuments(OperationContext* txn,
 /**
  * Creates the given role object in the given database.
  */
-Status insertRoleDocument(OperationContext* txn, const BSONObj& roleObj) {
+Status insertRoleDocument(OperationContext* opCtx, const BSONObj& roleObj) {
     Status status =
-        insertAuthzDocument(txn, AuthorizationManager::rolesCollectionNamespace, roleObj);
+        insertAuthzDocument(opCtx, AuthorizationManager::rolesCollectionNamespace, roleObj);
     if (status.isOK()) {
         return status;
     }
@@ -422,8 +422,8 @@ Status insertRoleDocument(OperationContext* txn, const BSONObj& roleObj) {
 /**
  * Updates the given role object with the given update modifier.
  */
-Status updateRoleDocument(OperationContext* txn, const RoleName& role, const BSONObj& updateObj) {
-    Status status = updateOneAuthzDocument(txn,
+Status updateRoleDocument(OperationContext* opCtx, const RoleName& role, const BSONObj& updateObj) {
+    Status status = updateOneAuthzDocument(opCtx,
                                            AuthorizationManager::rolesCollectionNamespace,
                                            BSON(AuthorizationManager::ROLE_NAME_FIELD_NAME
                                                 << role.getRole()
@@ -448,9 +448,9 @@ Status updateRoleDocument(OperationContext* txn, const RoleName& role, const BSO
  * Removes roles matching the given query.
  * Writes into *numRemoved the number of role documents that were modified.
  */
-Status removeRoleDocuments(OperationContext* txn, const BSONObj& query, long long* numRemoved) {
+Status removeRoleDocuments(OperationContext* opCtx, const BSONObj& query, long long* numRemoved) {
     Status status = removeAuthzDocuments(
-        txn, AuthorizationManager::rolesCollectionNamespace, query, numRemoved);
+        opCtx, AuthorizationManager::rolesCollectionNamespace, query, numRemoved);
     if (status.code() == ErrorCodes::UnknownError) {
         return Status(ErrorCodes::RoleModificationFailed, status.reason());
     }
@@ -460,9 +460,9 @@ Status removeRoleDocuments(OperationContext* txn, const BSONObj& query, long lon
 /**
  * Creates the given user object in the given database.
  */
-Status insertPrivilegeDocument(OperationContext* txn, const BSONObj& userObj) {
+Status insertPrivilegeDocument(OperationContext* opCtx, const BSONObj& userObj) {
     Status status =
-        insertAuthzDocument(txn, AuthorizationManager::usersCollectionNamespace, userObj);
+        insertAuthzDocument(opCtx, AuthorizationManager::usersCollectionNamespace, userObj);
     if (status.isOK()) {
         return status;
     }
@@ -481,10 +481,10 @@ Status insertPrivilegeDocument(OperationContext* txn, const BSONObj& userObj) {
 /**
  * Updates the given user object with the given update modifier.
  */
-Status updatePrivilegeDocument(OperationContext* txn,
+Status updatePrivilegeDocument(OperationContext* opCtx,
                                const UserName& user,
                                const BSONObj& updateObj) {
-    Status status = updateOneAuthzDocument(txn,
+    Status status = updateOneAuthzDocument(opCtx,
                                            AuthorizationManager::usersCollectionNamespace,
                                            BSON(AuthorizationManager::USER_NAME_FIELD_NAME
                                                 << user.getUser()
@@ -509,11 +509,11 @@ Status updatePrivilegeDocument(OperationContext* txn,
  * Removes users for the given database matching the given query.
  * Writes into *numRemoved the number of user documents that were modified.
  */
-Status removePrivilegeDocuments(OperationContext* txn,
+Status removePrivilegeDocuments(OperationContext* opCtx,
                                 const BSONObj& query,
                                 long long* numRemoved) {
     Status status = removeAuthzDocuments(
-        txn, AuthorizationManager::usersCollectionNamespace, query, numRemoved);
+        opCtx, AuthorizationManager::usersCollectionNamespace, query, numRemoved);
     if (status.code() == ErrorCodes::UnknownError) {
         return Status(ErrorCodes::UserModificationFailed, status.reason());
     }
@@ -524,11 +524,11 @@ Status removePrivilegeDocuments(OperationContext* txn,
  * Updates the auth schema version document to reflect the current state of the system.
  * 'foundSchemaVersion' is the authSchemaVersion to update with.
  */
-Status writeAuthSchemaVersionIfNeeded(OperationContext* txn,
+Status writeAuthSchemaVersionIfNeeded(OperationContext* opCtx,
                                       AuthorizationManager* authzManager,
                                       int foundSchemaVersion) {
     Status status = updateOneAuthzDocument(
-        txn,
+        opCtx,
         AuthorizationManager::versionCollectionNamespace,
         AuthorizationManager::versionDocumentQuery,
         BSON("$set" << BSON(AuthorizationManager::schemaVersionFieldName << foundSchemaVersion)),
@@ -546,9 +546,10 @@ Status writeAuthSchemaVersionIfNeeded(OperationContext* txn,
  * for the MongoDB 2.6 and 3.0 MongoDB-CR/SCRAM mixed auth mode.
  * Returns an error otherwise.
  */
-Status requireAuthSchemaVersion26Final(OperationContext* txn, AuthorizationManager* authzManager) {
+Status requireAuthSchemaVersion26Final(OperationContext* opCtx,
+                                       AuthorizationManager* authzManager) {
     int foundSchemaVersion;
-    Status status = authzManager->getAuthorizationVersion(txn, &foundSchemaVersion);
+    Status status = authzManager->getAuthorizationVersion(opCtx, &foundSchemaVersion);
     if (!status.isOK()) {
         return status;
     }
@@ -562,7 +563,7 @@ Status requireAuthSchemaVersion26Final(OperationContext* txn, AuthorizationManag
                           << " but found "
                           << foundSchemaVersion);
     }
-    return writeAuthSchemaVersionIfNeeded(txn, authzManager, foundSchemaVersion);
+    return writeAuthSchemaVersionIfNeeded(opCtx, authzManager, foundSchemaVersion);
 }
 
 /**
@@ -570,10 +571,10 @@ Status requireAuthSchemaVersion26Final(OperationContext* txn, AuthorizationManag
  * for MongoDB 2.6 during the upgrade process.
  * Returns an error otherwise.
  */
-Status requireAuthSchemaVersion26UpgradeOrFinal(OperationContext* txn,
+Status requireAuthSchemaVersion26UpgradeOrFinal(OperationContext* opCtx,
                                                 AuthorizationManager* authzManager) {
     int foundSchemaVersion;
-    Status status = authzManager->getAuthorizationVersion(txn, &foundSchemaVersion);
+    Status status = authzManager->getAuthorizationVersion(opCtx, &foundSchemaVersion);
     if (!status.isOK()) {
         return status;
     }
@@ -614,7 +615,7 @@ public:
         return auth::checkAuthForCreateUserCommand(client, dbname, cmdObj);
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int options,
@@ -670,10 +671,10 @@ public:
         userObjBuilder.append(AuthorizationManager::USER_NAME_FIELD_NAME, args.userName.getUser());
         userObjBuilder.append(AuthorizationManager::USER_DB_FIELD_NAME, args.userName.getDB());
 
-        ServiceContext* serviceContext = txn->getClient()->getServiceContext();
+        ServiceContext* serviceContext = opCtx->getClient()->getServiceContext();
         AuthorizationManager* authzManager = AuthorizationManager::get(serviceContext);
         int authzVersion;
-        status = authzManager->getAuthorizationVersion(txn, &authzVersion);
+        status = authzManager->getAuthorizationVersion(opCtx, &authzVersion);
         if (!status.isOK()) {
             return appendCommandStatus(result, status);
         }
@@ -708,7 +709,7 @@ public:
 
         stdx::lock_guard<stdx::mutex> lk(getAuthzDataMutex(serviceContext));
 
-        status = requireAuthSchemaVersion26Final(txn, authzManager);
+        status = requireAuthSchemaVersion26Final(opCtx, authzManager);
         if (!status.isOK()) {
             return appendCommandStatus(result, status);
         }
@@ -717,7 +718,7 @@ public:
         for (size_t i = 0; i < args.roles.size(); ++i) {
             BSONObj ignored;
             status = authzManager->getRoleDescription(
-                txn, args.roles[i], PrivilegeFormat::kOmit, &ignored);
+                opCtx, args.roles[i], PrivilegeFormat::kOmit, &ignored);
             if (!status.isOK()) {
                 return appendCommandStatus(result, status);
             }
@@ -728,7 +729,7 @@ public:
                              args.hasHashedPassword,
                              args.hasCustomData ? &args.customData : NULL,
                              args.roles);
-        status = insertPrivilegeDocument(txn, userObj);
+        status = insertPrivilegeDocument(opCtx, userObj);
         return appendCommandStatus(result, status);
     }
 
@@ -760,7 +761,7 @@ public:
         return auth::checkAuthForUpdateUserCommand(client, dbname, cmdObj);
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int options,
@@ -793,7 +794,7 @@ public:
 
             AuthorizationManager* authzManager = getGlobalAuthorizationManager();
             int authzVersion;
-            Status status = authzManager->getAuthorizationVersion(txn, &authzVersion);
+            Status status = authzManager->getAuthorizationVersion(opCtx, &authzVersion);
             if (!status.isOK()) {
                 return appendCommandStatus(result, status);
             }
@@ -815,11 +816,11 @@ public:
             updateSetBuilder.append("roles", rolesVectorToBSONArray(args.roles));
         }
 
-        ServiceContext* serviceContext = txn->getClient()->getServiceContext();
+        ServiceContext* serviceContext = opCtx->getClient()->getServiceContext();
         stdx::lock_guard<stdx::mutex> lk(getAuthzDataMutex(serviceContext));
 
         AuthorizationManager* authzManager = AuthorizationManager::get(serviceContext);
-        status = requireAuthSchemaVersion26Final(txn, authzManager);
+        status = requireAuthSchemaVersion26Final(opCtx, authzManager);
         if (!status.isOK()) {
             return appendCommandStatus(result, status);
         }
@@ -830,7 +831,7 @@ public:
             for (size_t i = 0; i < args.roles.size(); ++i) {
                 BSONObj ignored;
                 status = authzManager->getRoleDescription(
-                    txn, args.roles[i], PrivilegeFormat::kOmit, &ignored);
+                    opCtx, args.roles[i], PrivilegeFormat::kOmit, &ignored);
                 if (!status.isOK()) {
                     return appendCommandStatus(result, status);
                 }
@@ -844,7 +845,7 @@ public:
                              args.hasRoles ? &args.roles : NULL);
 
         status =
-            updatePrivilegeDocument(txn, args.userName, BSON("$set" << updateSetBuilder.done()));
+            updatePrivilegeDocument(opCtx, args.userName, BSON("$set" << updateSetBuilder.done()));
         // Must invalidate even on bad status - what if the write succeeded but the GLE failed?
         authzManager->invalidateUserByName(args.userName);
         return appendCommandStatus(result, status);
@@ -878,7 +879,7 @@ public:
         return auth::checkAuthForDropUserCommand(client, dbname, cmdObj);
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int options,
@@ -890,10 +891,10 @@ public:
             return appendCommandStatus(result, status);
         }
 
-        ServiceContext* serviceContext = txn->getClient()->getServiceContext();
+        ServiceContext* serviceContext = opCtx->getClient()->getServiceContext();
         stdx::lock_guard<stdx::mutex> lk(getAuthzDataMutex(serviceContext));
         AuthorizationManager* authzManager = AuthorizationManager::get(serviceContext);
-        status = requireAuthSchemaVersion26Final(txn, authzManager);
+        status = requireAuthSchemaVersion26Final(opCtx, authzManager);
         if (!status.isOK()) {
             return appendCommandStatus(result, status);
         }
@@ -901,7 +902,7 @@ public:
         audit::logDropUser(Client::getCurrent(), userName);
 
         long long nMatched;
-        status = removePrivilegeDocuments(txn,
+        status = removePrivilegeDocuments(opCtx,
                                           BSON(AuthorizationManager::USER_NAME_FIELD_NAME
                                                << userName.getUser()
                                                << AuthorizationManager::USER_DB_FIELD_NAME
@@ -947,7 +948,7 @@ public:
         return auth::checkAuthForDropAllUsersFromDatabaseCommand(client, dbname);
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int options,
@@ -957,11 +958,11 @@ public:
         if (!status.isOK()) {
             return appendCommandStatus(result, status);
         }
-        ServiceContext* serviceContext = txn->getClient()->getServiceContext();
+        ServiceContext* serviceContext = opCtx->getClient()->getServiceContext();
         stdx::lock_guard<stdx::mutex> lk(getAuthzDataMutex(serviceContext));
 
         AuthorizationManager* authzManager = AuthorizationManager::get(serviceContext);
-        status = requireAuthSchemaVersion26Final(txn, authzManager);
+        status = requireAuthSchemaVersion26Final(opCtx, authzManager);
         if (!status.isOK()) {
             return appendCommandStatus(result, status);
         }
@@ -970,7 +971,7 @@ public:
 
         long long numRemoved;
         status = removePrivilegeDocuments(
-            txn, BSON(AuthorizationManager::USER_DB_FIELD_NAME << dbname), &numRemoved);
+            opCtx, BSON(AuthorizationManager::USER_DB_FIELD_NAME << dbname), &numRemoved);
         // Must invalidate even on bad status - what if the write succeeded but the GLE failed?
         authzManager->invalidateUsersFromDB(dbname);
         if (!status.isOK()) {
@@ -1005,7 +1006,7 @@ public:
         return auth::checkAuthForGrantRolesToUserCommand(client, dbname, cmdObj);
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int options,
@@ -1019,18 +1020,18 @@ public:
             return appendCommandStatus(result, status);
         }
 
-        ServiceContext* serviceContext = txn->getClient()->getServiceContext();
+        ServiceContext* serviceContext = opCtx->getClient()->getServiceContext();
         stdx::lock_guard<stdx::mutex> lk(getAuthzDataMutex(serviceContext));
 
         AuthorizationManager* authzManager = AuthorizationManager::get(serviceContext);
-        status = requireAuthSchemaVersion26Final(txn, authzManager);
+        status = requireAuthSchemaVersion26Final(opCtx, authzManager);
         if (!status.isOK()) {
             return appendCommandStatus(result, status);
         }
 
         UserName userName(userNameString, dbname);
         unordered_set<RoleName> userRoles;
-        status = getCurrentUserRoles(txn, authzManager, userName, &userRoles);
+        status = getCurrentUserRoles(opCtx, authzManager, userName, &userRoles);
         if (!status.isOK()) {
             return appendCommandStatus(result, status);
         }
@@ -1039,7 +1040,7 @@ public:
             RoleName& roleName = *it;
             BSONObj roleDoc;
             status =
-                authzManager->getRoleDescription(txn, roleName, PrivilegeFormat::kOmit, &roleDoc);
+                authzManager->getRoleDescription(opCtx, roleName, PrivilegeFormat::kOmit, &roleDoc);
             if (!status.isOK()) {
                 return appendCommandStatus(result, status);
             }
@@ -1050,7 +1051,7 @@ public:
         audit::logGrantRolesToUser(Client::getCurrent(), userName, roles);
         BSONArray newRolesBSONArray = roleSetToBSONArray(userRoles);
         status = updatePrivilegeDocument(
-            txn, userName, BSON("$set" << BSON("roles" << newRolesBSONArray)));
+            opCtx, userName, BSON("$set" << BSON("roles" << newRolesBSONArray)));
         // Must invalidate even on bad status - what if the write succeeded but the GLE failed?
         authzManager->invalidateUserByName(userName);
         return appendCommandStatus(result, status);
@@ -1080,7 +1081,7 @@ public:
         return auth::checkAuthForRevokeRolesFromUserCommand(client, dbname, cmdObj);
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int options,
@@ -1094,18 +1095,18 @@ public:
             return appendCommandStatus(result, status);
         }
 
-        ServiceContext* serviceContext = txn->getClient()->getServiceContext();
+        ServiceContext* serviceContext = opCtx->getClient()->getServiceContext();
         stdx::lock_guard<stdx::mutex> lk(getAuthzDataMutex(serviceContext));
 
         AuthorizationManager* authzManager = AuthorizationManager::get(serviceContext);
-        status = requireAuthSchemaVersion26Final(txn, authzManager);
+        status = requireAuthSchemaVersion26Final(opCtx, authzManager);
         if (!status.isOK()) {
             return appendCommandStatus(result, status);
         }
 
         UserName userName(userNameString, dbname);
         unordered_set<RoleName> userRoles;
-        status = getCurrentUserRoles(txn, authzManager, userName, &userRoles);
+        status = getCurrentUserRoles(opCtx, authzManager, userName, &userRoles);
         if (!status.isOK()) {
             return appendCommandStatus(result, status);
         }
@@ -1114,7 +1115,7 @@ public:
             RoleName& roleName = *it;
             BSONObj roleDoc;
             status =
-                authzManager->getRoleDescription(txn, roleName, PrivilegeFormat::kOmit, &roleDoc);
+                authzManager->getRoleDescription(opCtx, roleName, PrivilegeFormat::kOmit, &roleDoc);
             if (!status.isOK()) {
                 return appendCommandStatus(result, status);
             }
@@ -1125,7 +1126,7 @@ public:
         audit::logRevokeRolesFromUser(Client::getCurrent(), userName, roles);
         BSONArray newRolesBSONArray = roleSetToBSONArray(userRoles);
         status = updatePrivilegeDocument(
-            txn, userName, BSON("$set" << BSON("roles" << newRolesBSONArray)));
+            opCtx, userName, BSON("$set" << BSON("roles" << newRolesBSONArray)));
         // Must invalidate even on bad status - what if the write succeeded but the GLE failed?
         authzManager->invalidateUserByName(userName);
         return appendCommandStatus(result, status);
@@ -1159,7 +1160,7 @@ public:
         return auth::checkAuthForUsersInfoCommand(client, dbname, cmdObj);
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int options,
@@ -1171,7 +1172,7 @@ public:
             return appendCommandStatus(result, status);
         }
 
-        status = requireAuthSchemaVersion26UpgradeOrFinal(txn, getGlobalAuthorizationManager());
+        status = requireAuthSchemaVersion26UpgradeOrFinal(opCtx, getGlobalAuthorizationManager());
         if (!status.isOK()) {
             return appendCommandStatus(result, status);
         }
@@ -1190,7 +1191,7 @@ public:
             for (size_t i = 0; i < args.userNames.size(); ++i) {
                 BSONObj userDetails;
                 status = getGlobalAuthorizationManager()->getUserDescription(
-                    txn, args.userNames[i], &userDetails);
+                    opCtx, args.userNames[i], &userDetails);
                 if (status.code() == ErrorCodes::UserNotFound) {
                     continue;
                 }
@@ -1236,7 +1237,7 @@ public:
             }
             const stdx::function<void(const BSONObj&)> function = stdx::bind(
                 appendBSONObjToBSONArrayBuilder, &usersArrayBuilder, stdx::placeholders::_1);
-            queryAuthzDocument(txn,
+            queryAuthzDocument(opCtx,
                                AuthorizationManager::usersCollectionNamespace,
                                queryBuilder.done(),
                                projection,
@@ -1270,7 +1271,7 @@ public:
         return auth::checkAuthForCreateRoleCommand(client, dbname, cmdObj);
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int options,
@@ -1334,17 +1335,17 @@ public:
 
         roleObjBuilder.append("roles", rolesVectorToBSONArray(args.roles));
 
-        ServiceContext* serviceContext = txn->getClient()->getServiceContext();
+        ServiceContext* serviceContext = opCtx->getClient()->getServiceContext();
         stdx::lock_guard<stdx::mutex> lk(getAuthzDataMutex(serviceContext));
 
         AuthorizationManager* authzManager = AuthorizationManager::get(serviceContext);
-        status = requireAuthSchemaVersion26Final(txn, authzManager);
+        status = requireAuthSchemaVersion26Final(opCtx, authzManager);
         if (!status.isOK()) {
             return appendCommandStatus(result, status);
         }
 
         // Role existence has to be checked after acquiring the update lock
-        status = checkOkayToGrantRolesToRole(txn, args.roleName, args.roles, authzManager);
+        status = checkOkayToGrantRolesToRole(opCtx, args.roleName, args.roles, authzManager);
         if (!status.isOK()) {
             return appendCommandStatus(result, status);
         }
@@ -1356,7 +1357,7 @@ public:
 
         audit::logCreateRole(Client::getCurrent(), args.roleName, args.roles, args.privileges);
 
-        status = insertRoleDocument(txn, roleObjBuilder.done());
+        status = insertRoleDocument(opCtx, roleObjBuilder.done());
         return appendCommandStatus(result, status);
     }
 
@@ -1384,7 +1385,7 @@ public:
         return auth::checkAuthForUpdateRoleCommand(client, dbname, cmdObj);
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int options,
@@ -1418,25 +1419,25 @@ public:
             updateSetBuilder.append("roles", rolesVectorToBSONArray(args.roles));
         }
 
-        ServiceContext* serviceContext = txn->getClient()->getServiceContext();
+        ServiceContext* serviceContext = opCtx->getClient()->getServiceContext();
         stdx::lock_guard<stdx::mutex> lk(getAuthzDataMutex(serviceContext));
 
         AuthorizationManager* authzManager = AuthorizationManager::get(serviceContext);
-        status = requireAuthSchemaVersion26Final(txn, authzManager);
+        status = requireAuthSchemaVersion26Final(opCtx, authzManager);
         if (!status.isOK()) {
             return appendCommandStatus(result, status);
         }
 
         // Role existence has to be checked after acquiring the update lock
         BSONObj ignored;
-        status =
-            authzManager->getRoleDescription(txn, args.roleName, PrivilegeFormat::kOmit, &ignored);
+        status = authzManager->getRoleDescription(
+            opCtx, args.roleName, PrivilegeFormat::kOmit, &ignored);
         if (!status.isOK()) {
             return appendCommandStatus(result, status);
         }
 
         if (args.hasRoles) {
-            status = checkOkayToGrantRolesToRole(txn, args.roleName, args.roles, authzManager);
+            status = checkOkayToGrantRolesToRole(opCtx, args.roleName, args.roles, authzManager);
             if (!status.isOK()) {
                 return appendCommandStatus(result, status);
             }
@@ -1454,7 +1455,7 @@ public:
                              args.hasRoles ? &args.roles : NULL,
                              args.hasPrivileges ? &args.privileges : NULL);
 
-        status = updateRoleDocument(txn, args.roleName, BSON("$set" << updateSetBuilder.done()));
+        status = updateRoleDocument(opCtx, args.roleName, BSON("$set" << updateSetBuilder.done()));
         // Must invalidate even on bad status - what if the write succeeded but the GLE failed?
         authzManager->invalidateUserCache();
         return appendCommandStatus(result, status);
@@ -1483,7 +1484,7 @@ public:
         return auth::checkAuthForGrantPrivilegesToRoleCommand(client, dbname, cmdObj);
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int options,
@@ -1498,11 +1499,11 @@ public:
             return appendCommandStatus(result, status);
         }
 
-        ServiceContext* serviceContext = txn->getClient()->getServiceContext();
+        ServiceContext* serviceContext = opCtx->getClient()->getServiceContext();
         stdx::lock_guard<stdx::mutex> lk(getAuthzDataMutex(serviceContext));
 
         AuthorizationManager* authzManager = AuthorizationManager::get(serviceContext);
-        status = requireAuthSchemaVersion26Final(txn, authzManager);
+        status = requireAuthSchemaVersion26Final(opCtx, authzManager);
         if (!status.isOK()) {
             return appendCommandStatus(result, status);
         }
@@ -1522,7 +1523,7 @@ public:
 
         BSONObj roleDoc;
         status = authzManager->getRoleDescription(
-            txn, roleName, PrivilegeFormat::kShowSeparate, &roleDoc);
+            opCtx, roleName, PrivilegeFormat::kShowSeparate, &roleDoc);
         if (!status.isOK()) {
             return appendCommandStatus(result, status);
         }
@@ -1562,7 +1563,7 @@ public:
 
         audit::logGrantPrivilegesToRole(Client::getCurrent(), roleName, privilegesToAdd);
 
-        status = updateRoleDocument(txn, roleName, updateBSONBuilder.done());
+        status = updateRoleDocument(opCtx, roleName, updateBSONBuilder.done());
         // Must invalidate even on bad status - what if the write succeeded but the GLE failed?
         authzManager->invalidateUserCache();
         return appendCommandStatus(result, status);
@@ -1592,7 +1593,7 @@ public:
         return auth::checkAuthForRevokePrivilegesFromRoleCommand(client, dbname, cmdObj);
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int options,
@@ -1606,11 +1607,11 @@ public:
             return appendCommandStatus(result, status);
         }
 
-        ServiceContext* serviceContext = txn->getClient()->getServiceContext();
+        ServiceContext* serviceContext = opCtx->getClient()->getServiceContext();
         stdx::lock_guard<stdx::mutex> lk(getAuthzDataMutex(serviceContext));
 
         AuthorizationManager* authzManager = AuthorizationManager::get(serviceContext);
-        status = requireAuthSchemaVersion26Final(txn, authzManager);
+        status = requireAuthSchemaVersion26Final(opCtx, authzManager);
         if (!status.isOK()) {
             return appendCommandStatus(result, status);
         }
@@ -1625,7 +1626,7 @@ public:
 
         BSONObj roleDoc;
         status = authzManager->getRoleDescription(
-            txn, roleName, PrivilegeFormat::kShowSeparate, &roleDoc);
+            opCtx, roleName, PrivilegeFormat::kShowSeparate, &roleDoc);
         if (!status.isOK()) {
             return appendCommandStatus(result, status);
         }
@@ -1673,7 +1674,7 @@ public:
 
         BSONObjBuilder updateBSONBuilder;
         updateObj.writeTo(&updateBSONBuilder);
-        status = updateRoleDocument(txn, roleName, updateBSONBuilder.done());
+        status = updateRoleDocument(opCtx, roleName, updateBSONBuilder.done());
         // Must invalidate even on bad status - what if the write succeeded but the GLE failed?
         authzManager->invalidateUserCache();
         return appendCommandStatus(result, status);
@@ -1703,7 +1704,7 @@ public:
         return auth::checkAuthForGrantRolesToRoleCommand(client, dbname, cmdObj);
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int options,
@@ -1726,24 +1727,25 @@ public:
                                      << " is a built-in role and cannot be modified."));
         }
 
-        ServiceContext* serviceContext = txn->getClient()->getServiceContext();
+        ServiceContext* serviceContext = opCtx->getClient()->getServiceContext();
         stdx::lock_guard<stdx::mutex> lk(getAuthzDataMutex(serviceContext));
 
         AuthorizationManager* authzManager = AuthorizationManager::get(serviceContext);
-        status = requireAuthSchemaVersion26Final(txn, authzManager);
+        status = requireAuthSchemaVersion26Final(opCtx, authzManager);
         if (!status.isOK()) {
             return appendCommandStatus(result, status);
         }
 
         // Role existence has to be checked after acquiring the update lock
         BSONObj roleDoc;
-        status = authzManager->getRoleDescription(txn, roleName, PrivilegeFormat::kOmit, &roleDoc);
+        status =
+            authzManager->getRoleDescription(opCtx, roleName, PrivilegeFormat::kOmit, &roleDoc);
         if (!status.isOK()) {
             return appendCommandStatus(result, status);
         }
 
         // Check for cycles
-        status = checkOkayToGrantRolesToRole(txn, roleName, rolesToAdd, authzManager);
+        status = checkOkayToGrantRolesToRole(opCtx, roleName, rolesToAdd, authzManager);
         if (!status.isOK()) {
             return appendCommandStatus(result, status);
         }
@@ -1764,7 +1766,7 @@ public:
         audit::logGrantRolesToRole(Client::getCurrent(), roleName, rolesToAdd);
 
         status = updateRoleDocument(
-            txn, roleName, BSON("$set" << BSON("roles" << rolesVectorToBSONArray(directRoles))));
+            opCtx, roleName, BSON("$set" << BSON("roles" << rolesVectorToBSONArray(directRoles))));
         // Must invalidate even on bad status - what if the write succeeded but the GLE failed?
         authzManager->invalidateUserCache();
         return appendCommandStatus(result, status);
@@ -1794,7 +1796,7 @@ public:
         return auth::checkAuthForRevokeRolesFromRoleCommand(client, dbname, cmdObj);
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int options,
@@ -1808,11 +1810,11 @@ public:
             return appendCommandStatus(result, status);
         }
 
-        ServiceContext* serviceContext = txn->getClient()->getServiceContext();
+        ServiceContext* serviceContext = opCtx->getClient()->getServiceContext();
         stdx::lock_guard<stdx::mutex> lk(getAuthzDataMutex(serviceContext));
 
         AuthorizationManager* authzManager = AuthorizationManager::get(serviceContext);
-        status = requireAuthSchemaVersion26Final(txn, authzManager);
+        status = requireAuthSchemaVersion26Final(opCtx, authzManager);
         if (!status.isOK()) {
             return appendCommandStatus(result, status);
         }
@@ -1827,7 +1829,8 @@ public:
         }
 
         BSONObj roleDoc;
-        status = authzManager->getRoleDescription(txn, roleName, PrivilegeFormat::kOmit, &roleDoc);
+        status =
+            authzManager->getRoleDescription(opCtx, roleName, PrivilegeFormat::kOmit, &roleDoc);
         if (!status.isOK()) {
             return appendCommandStatus(result, status);
         }
@@ -1850,7 +1853,7 @@ public:
         audit::logRevokeRolesFromRole(Client::getCurrent(), roleName, rolesToRemove);
 
         status = updateRoleDocument(
-            txn, roleName, BSON("$set" << BSON("roles" << rolesVectorToBSONArray(roles))));
+            opCtx, roleName, BSON("$set" << BSON("roles" << rolesVectorToBSONArray(roles))));
         // Must invalidate even on bad status - what if the write succeeded but the GLE failed?
         authzManager->invalidateUserCache();
         return appendCommandStatus(result, status);
@@ -1884,7 +1887,7 @@ public:
         return auth::checkAuthForDropRoleCommand(client, dbname, cmdObj);
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int options,
@@ -1896,11 +1899,11 @@ public:
             return appendCommandStatus(result, status);
         }
 
-        ServiceContext* serviceContext = txn->getClient()->getServiceContext();
+        ServiceContext* serviceContext = opCtx->getClient()->getServiceContext();
         stdx::lock_guard<stdx::mutex> lk(getAuthzDataMutex(serviceContext));
 
         AuthorizationManager* authzManager = AuthorizationManager::get(serviceContext);
-        status = requireAuthSchemaVersion26Final(txn, authzManager);
+        status = requireAuthSchemaVersion26Final(opCtx, authzManager);
         if (!status.isOK()) {
             return appendCommandStatus(result, status);
         }
@@ -1914,7 +1917,8 @@ public:
         }
 
         BSONObj roleDoc;
-        status = authzManager->getRoleDescription(txn, roleName, PrivilegeFormat::kOmit, &roleDoc);
+        status =
+            authzManager->getRoleDescription(opCtx, roleName, PrivilegeFormat::kOmit, &roleDoc);
         if (!status.isOK()) {
             return appendCommandStatus(result, status);
         }
@@ -1922,7 +1926,7 @@ public:
         // Remove this role from all users
         long long nMatched;
         status = updateAuthzDocuments(
-            txn,
+            opCtx,
             AuthorizationManager::usersCollectionNamespace,
             BSON("roles" << BSON("$elemMatch" << BSON(AuthorizationManager::ROLE_NAME_FIELD_NAME
                                                       << roleName.getRole()
@@ -1951,7 +1955,7 @@ public:
 
         // Remove this role from all other roles
         status = updateAuthzDocuments(
-            txn,
+            opCtx,
             AuthorizationManager::rolesCollectionNamespace,
             BSON("roles" << BSON("$elemMatch" << BSON(AuthorizationManager::ROLE_NAME_FIELD_NAME
                                                       << roleName.getRole()
@@ -1980,7 +1984,7 @@ public:
 
         audit::logDropRole(Client::getCurrent(), roleName);
         // Finally, remove the actual role document
-        status = removeRoleDocuments(txn,
+        status = removeRoleDocuments(opCtx,
                                      BSON(AuthorizationManager::ROLE_NAME_FIELD_NAME
                                           << roleName.getRole()
                                           << AuthorizationManager::ROLE_DB_FIELD_NAME
@@ -2038,7 +2042,7 @@ public:
         return auth::checkAuthForDropAllRolesFromDatabaseCommand(client, dbname);
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int options,
@@ -2049,11 +2053,11 @@ public:
             return appendCommandStatus(result, status);
         }
 
-        ServiceContext* serviceContext = txn->getClient()->getServiceContext();
+        ServiceContext* serviceContext = opCtx->getClient()->getServiceContext();
         stdx::lock_guard<stdx::mutex> lk(getAuthzDataMutex(serviceContext));
 
         AuthorizationManager* authzManager = AuthorizationManager::get(serviceContext);
-        status = requireAuthSchemaVersion26Final(txn, authzManager);
+        status = requireAuthSchemaVersion26Final(opCtx, authzManager);
         if (!status.isOK()) {
             return appendCommandStatus(result, status);
         }
@@ -2061,7 +2065,7 @@ public:
         // Remove these roles from all users
         long long nMatched;
         status = updateAuthzDocuments(
-            txn,
+            opCtx,
             AuthorizationManager::usersCollectionNamespace,
             BSON("roles" << BSON(AuthorizationManager::ROLE_DB_FIELD_NAME << dbname)),
             BSON("$pull" << BSON("roles"
@@ -2087,7 +2091,7 @@ public:
         std::string sourceFieldName = str::stream() << "roles."
                                                     << AuthorizationManager::ROLE_DB_FIELD_NAME;
         status = updateAuthzDocuments(
-            txn,
+            opCtx,
             AuthorizationManager::rolesCollectionNamespace,
             BSON(sourceFieldName << dbname),
             BSON("$pull" << BSON("roles"
@@ -2112,7 +2116,7 @@ public:
         audit::logDropAllRolesFromDatabase(Client::getCurrent(), dbname);
         // Finally, remove the actual role documents
         status = removeRoleDocuments(
-            txn, BSON(AuthorizationManager::ROLE_DB_FIELD_NAME << dbname), &nMatched);
+            opCtx, BSON(AuthorizationManager::ROLE_DB_FIELD_NAME << dbname), &nMatched);
         // Must invalidate even on bad status - what if the write succeeded but the GLE failed?
         authzManager->invalidateUserCache();
         if (!status.isOK()) {
@@ -2182,7 +2186,7 @@ public:
         return auth::checkAuthForRolesInfoCommand(client, dbname, cmdObj);
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int options,
@@ -2194,7 +2198,7 @@ public:
             return appendCommandStatus(result, status);
         }
 
-        status = requireAuthSchemaVersion26UpgradeOrFinal(txn, getGlobalAuthorizationManager());
+        status = requireAuthSchemaVersion26UpgradeOrFinal(opCtx, getGlobalAuthorizationManager());
         if (!status.isOK()) {
             return appendCommandStatus(result, status);
         }
@@ -2202,7 +2206,7 @@ public:
         if (args.allForDB) {
             std::vector<BSONObj> rolesDocs;
             status = getGlobalAuthorizationManager()->getRoleDescriptionsForDB(
-                txn, dbname, args.privilegeFormat, args.showBuiltinRoles, &rolesDocs);
+                opCtx, dbname, args.privilegeFormat, args.showBuiltinRoles, &rolesDocs);
             if (!status.isOK()) {
                 return appendCommandStatus(result, status);
             }
@@ -2221,7 +2225,7 @@ public:
         } else {
             BSONObj roleDetails;
             status = getGlobalAuthorizationManager()->getRolesDescription(
-                txn, args.roleNames, args.privilegeFormat, &roleDetails);
+                opCtx, args.roleNames, args.privilegeFormat, &roleDetails);
             if (!status.isOK()) {
                 return appendCommandStatus(result, status);
             }
@@ -2264,7 +2268,7 @@ public:
         return auth::checkAuthForInvalidateUserCacheCommand(client);
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int options,
@@ -2303,7 +2307,7 @@ public:
         return auth::checkAuthForGetUserCacheGenerationCommand(client);
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int options,
@@ -2451,7 +2455,7 @@ public:
      * admin.system.users collection.
      * Also removes any users it encounters from the usersToDrop set.
      */
-    static void addUser(OperationContext* txn,
+    static void addUser(OperationContext* opCtx,
                         AuthorizationManager* authzManager,
                         StringData db,
                         bool update,
@@ -2464,7 +2468,7 @@ public:
 
         if (update && usersToDrop->count(userName)) {
             auditCreateOrUpdateUser(userObj, false);
-            Status status = updatePrivilegeDocument(txn, userName, userObj);
+            Status status = updatePrivilegeDocument(opCtx, userName, userObj);
             if (!status.isOK()) {
                 // Match the behavior of mongorestore to continue on failure
                 warning() << "Could not update user " << userName
@@ -2472,7 +2476,7 @@ public:
             }
         } else {
             auditCreateOrUpdateUser(userObj, true);
-            Status status = insertPrivilegeDocument(txn, userObj);
+            Status status = insertPrivilegeDocument(opCtx, userObj);
             if (!status.isOK()) {
                 // Match the behavior of mongorestore to continue on failure
                 warning() << "Could not insert user " << userName
@@ -2489,7 +2493,7 @@ public:
      * admin.system.roles collection.
      * Also removes any roles it encounters from the rolesToDrop set.
      */
-    static void addRole(OperationContext* txn,
+    static void addRole(OperationContext* opCtx,
                         AuthorizationManager* authzManager,
                         StringData db,
                         bool update,
@@ -2502,7 +2506,7 @@ public:
 
         if (update && rolesToDrop->count(roleName)) {
             auditCreateOrUpdateRole(roleObj, false);
-            Status status = updateRoleDocument(txn, roleName, roleObj);
+            Status status = updateRoleDocument(opCtx, roleName, roleObj);
             if (!status.isOK()) {
                 // Match the behavior of mongorestore to continue on failure
                 warning() << "Could not update role " << roleName
@@ -2510,7 +2514,7 @@ public:
             }
         } else {
             auditCreateOrUpdateRole(roleObj, true);
-            Status status = insertRoleDocument(txn, roleObj);
+            Status status = insertRoleDocument(opCtx, roleObj);
             if (!status.isOK()) {
                 // Match the behavior of mongorestore to continue on failure
                 warning() << "Could not insert role " << roleName
@@ -2524,7 +2528,7 @@ public:
      * Moves all user objects from usersCollName into admin.system.users.  If drop is true,
      * removes any users that were in admin.system.users but not in usersCollName.
      */
-    Status processUsers(OperationContext* txn,
+    Status processUsers(OperationContext* opCtx,
                         AuthorizationManager* authzManager,
                         StringData usersCollName,
                         StringData db,
@@ -2550,7 +2554,7 @@ public:
                                   << 1);
 
             Status status =
-                queryAuthzDocument(txn,
+                queryAuthzDocument(opCtx,
                                    AuthorizationManager::usersCollectionNamespace,
                                    query,
                                    fields,
@@ -2563,12 +2567,12 @@ public:
         }
 
         Status status = queryAuthzDocument(
-            txn,
+            opCtx,
             NamespaceString(usersCollName),
             db.empty() ? BSONObj() : BSON(AuthorizationManager::USER_DB_FIELD_NAME << db),
             BSONObj(),
             stdx::bind(&CmdMergeAuthzCollections::addUser,
-                       txn,
+                       opCtx,
                        authzManager,
                        db,
                        drop,
@@ -2585,7 +2589,7 @@ public:
                  ++it) {
                 const UserName& userName = *it;
                 audit::logDropUser(Client::getCurrent(), userName);
-                status = removePrivilegeDocuments(txn,
+                status = removePrivilegeDocuments(opCtx,
                                                   BSON(AuthorizationManager::USER_NAME_FIELD_NAME
                                                        << userName.getUser().toString()
                                                        << AuthorizationManager::USER_DB_FIELD_NAME
@@ -2605,7 +2609,7 @@ public:
      * Moves all user objects from usersCollName into admin.system.users.  If drop is true,
      * removes any users that were in admin.system.users but not in usersCollName.
      */
-    Status processRoles(OperationContext* txn,
+    Status processRoles(OperationContext* opCtx,
                         AuthorizationManager* authzManager,
                         StringData rolesCollName,
                         StringData db,
@@ -2630,7 +2634,7 @@ public:
                                   << 1);
 
             Status status =
-                queryAuthzDocument(txn,
+                queryAuthzDocument(opCtx,
                                    AuthorizationManager::rolesCollectionNamespace,
                                    query,
                                    fields,
@@ -2643,12 +2647,12 @@ public:
         }
 
         Status status = queryAuthzDocument(
-            txn,
+            opCtx,
             NamespaceString(rolesCollName),
             db.empty() ? BSONObj() : BSON(AuthorizationManager::ROLE_DB_FIELD_NAME << db),
             BSONObj(),
             stdx::bind(&CmdMergeAuthzCollections::addRole,
-                       txn,
+                       opCtx,
                        authzManager,
                        db,
                        drop,
@@ -2665,7 +2669,7 @@ public:
                  ++it) {
                 const RoleName& roleName = *it;
                 audit::logDropRole(Client::getCurrent(), roleName);
-                status = removeRoleDocuments(txn,
+                status = removeRoleDocuments(opCtx,
                                              BSON(AuthorizationManager::ROLE_NAME_FIELD_NAME
                                                   << roleName.getRole().toString()
                                                   << AuthorizationManager::ROLE_DB_FIELD_NAME
@@ -2681,7 +2685,7 @@ public:
         return Status::OK();
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int options,
@@ -2701,24 +2705,26 @@ public:
                        "\"tempRolescollection\""));
         }
 
-        ServiceContext* serviceContext = txn->getClient()->getServiceContext();
+        ServiceContext* serviceContext = opCtx->getClient()->getServiceContext();
         stdx::lock_guard<stdx::mutex> lk(getAuthzDataMutex(serviceContext));
 
         AuthorizationManager* authzManager = AuthorizationManager::get(serviceContext);
-        status = requireAuthSchemaVersion26Final(txn, authzManager);
+        status = requireAuthSchemaVersion26Final(opCtx, authzManager);
         if (!status.isOK()) {
             return appendCommandStatus(result, status);
         }
 
         if (!args.usersCollName.empty()) {
-            Status status = processUsers(txn, authzManager, args.usersCollName, args.db, args.drop);
+            Status status =
+                processUsers(opCtx, authzManager, args.usersCollName, args.db, args.drop);
             if (!status.isOK()) {
                 return appendCommandStatus(result, status);
             }
         }
 
         if (!args.rolesCollName.empty()) {
-            Status status = processRoles(txn, authzManager, args.rolesCollName, args.db, args.drop);
+            Status status =
+                processRoles(opCtx, authzManager, args.rolesCollName, args.db, args.drop);
             if (!status.isOK()) {
                 return appendCommandStatus(result, status);
             }
@@ -2742,7 +2748,7 @@ Status logUpgradeFailed(const Status& status) {
  *
  * Throws a DBException on errors.
  */
-void updateUserCredentials(OperationContext* txn,
+void updateUserCredentials(OperationContext* opCtx,
                            const StringData& sourceDB,
                            const BSONObj& userDoc) {
     // Skip users in $external, SERVER-18475
@@ -2789,7 +2795,7 @@ void updateUserCredentials(OperationContext* txn,
     }
 
     uassertStatusOK(updateOneAuthzDocument(
-        txn, NamespaceString("admin", "system.users"), query, updateBuilder.obj(), true));
+        opCtx, NamespaceString("admin", "system.users"), query, updateBuilder.obj(), true));
 }
 
 /** Loop through all the user documents in the admin.system.users collection.
@@ -2798,20 +2804,20 @@ void updateUserCredentials(OperationContext* txn,
  *   2. Remove the MONGODB-CR hash
  *   3. Add SCRAM credentials to the user document credentials section
  */
-Status updateCredentials(OperationContext* txn) {
+Status updateCredentials(OperationContext* opCtx) {
     // Loop through and update the user documents in admin.system.users.
-    Status status =
-        queryAuthzDocument(txn,
-                           NamespaceString("admin", "system.users"),
-                           BSONObj(),
-                           BSONObj(),
-                           stdx::bind(updateUserCredentials, txn, "admin", stdx::placeholders::_1));
+    Status status = queryAuthzDocument(
+        opCtx,
+        NamespaceString("admin", "system.users"),
+        BSONObj(),
+        BSONObj(),
+        stdx::bind(updateUserCredentials, opCtx, "admin", stdx::placeholders::_1));
     if (!status.isOK())
         return logUpgradeFailed(status);
 
     // Update the schema version document.
     status =
-        updateOneAuthzDocument(txn,
+        updateOneAuthzDocument(opCtx,
                                AuthorizationManager::versionCollectionNamespace,
                                AuthorizationManager::versionDocumentQuery,
                                BSON("$set" << BSON(AuthorizationManager::schemaVersionFieldName
@@ -2836,11 +2842,11 @@ Status updateCredentials(OperationContext* txn) {
  * On failure, returns a status other than Status::OK().  In this case, is is typically safe
  * to try again.
  */
-Status upgradeAuthSchemaStep(OperationContext* txn,
+Status upgradeAuthSchemaStep(OperationContext* opCtx,
                              AuthorizationManager* authzManager,
                              bool* isDone) {
     int authzVersion;
-    Status status = authzManager->getAuthorizationVersion(txn, &authzVersion);
+    Status status = authzManager->getAuthorizationVersion(opCtx, &authzVersion);
     if (!status.isOK()) {
         return status;
     }
@@ -2848,7 +2854,7 @@ Status upgradeAuthSchemaStep(OperationContext* txn,
     switch (authzVersion) {
         case AuthorizationManager::schemaVersion26Final:
         case AuthorizationManager::schemaVersion28SCRAM: {
-            Status status = updateCredentials(txn);
+            Status status = updateCredentials(opCtx);
             if (status.isOK())
                 *isDone = true;
             return status;
@@ -2874,7 +2880,9 @@ Status upgradeAuthSchemaStep(OperationContext* txn,
  * progress performing the upgrade, and the specific code and message in the returned status
  * may provide additional information.
  */
-Status upgradeAuthSchema(OperationContext* txn, AuthorizationManager* authzManager, int maxSteps) {
+Status upgradeAuthSchema(OperationContext* opCtx,
+                         AuthorizationManager* authzManager,
+                         int maxSteps) {
     if (maxSteps < 1) {
         return Status(ErrorCodes::BadValue,
                       "Minimum value for maxSteps parameter to upgradeAuthSchema is 1");
@@ -2882,7 +2890,7 @@ Status upgradeAuthSchema(OperationContext* txn, AuthorizationManager* authzManag
     authzManager->invalidateUserCache();
     for (int i = 0; i < maxSteps; ++i) {
         bool isDone;
-        Status status = upgradeAuthSchemaStep(txn, authzManager, &isDone);
+        Status status = upgradeAuthSchemaStep(opCtx, authzManager, &isDone);
         authzManager->invalidateUserCache();
         if (!status.isOK() || isDone) {
             return status;
@@ -2919,7 +2927,7 @@ public:
         return auth::checkAuthForAuthSchemaUpgradeCommand(client);
     }
 
-    virtual bool run(OperationContext* txn,
+    virtual bool run(OperationContext* opCtx,
                      const string& dbname,
                      BSONObj& cmdObj,
                      int options,
@@ -2931,12 +2939,12 @@ public:
             return appendCommandStatus(result, status);
         }
 
-        ServiceContext* serviceContext = txn->getClient()->getServiceContext();
+        ServiceContext* serviceContext = opCtx->getClient()->getServiceContext();
         AuthorizationManager* authzManager = AuthorizationManager::get(serviceContext);
 
         stdx::lock_guard<stdx::mutex> lk(getAuthzDataMutex(serviceContext));
 
-        status = upgradeAuthSchema(txn, authzManager, parsedArgs.maxSteps);
+        status = upgradeAuthSchema(opCtx, authzManager, parsedArgs.maxSteps);
         if (status.isOK())
             result.append("done", true);
         return appendCommandStatus(result, status);
diff --git a/src/mongo/db/commands/validate.cpp b/src/mongo/db/commands/validate.cpp
index 02c577da9c8..2fc05974986 100644
--- a/src/mongo/db/commands/validate.cpp
+++ b/src/mongo/db/commands/validate.cpp
@@ -75,7 +75,7 @@ public:
     }
     //{ validate: "collectionnamewithoutthedbpart" [, scandata: <bool>] [, full: <bool> } */
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const string& dbname,
              BSONObj& cmdObj,
              int,
@@ -109,11 +109,11 @@ public:
             LOG(0) << "CMD: validate " << nss.ns();
         }
 
-        AutoGetDb ctx(txn, nss.db(), MODE_IX);
-        Lock::CollectionLock collLk(txn->lockState(), nss.ns(), MODE_X);
+        AutoGetDb ctx(opCtx, nss.db(), MODE_IX);
+        Lock::CollectionLock collLk(opCtx->lockState(), nss.ns(), MODE_X);
         Collection* collection = ctx.getDb() ? ctx.getDb()->getCollection(nss) : NULL;
         if (!collection) {
-            if (ctx.getDb() && ctx.getDb()->getViewCatalog()->lookup(txn, nss.ns())) {
+            if (ctx.getDb() && ctx.getDb()->getViewCatalog()->lookup(opCtx, nss.ns())) {
                 errmsg = "Cannot validate a view";
                 return appendCommandStatus(result, {ErrorCodes::CommandNotSupportedOnView, errmsg});
             }
@@ -125,7 +125,7 @@ public:
         result.append("ns", nss.ns());
 
         ValidateResults results;
-        Status status = collection->validate(txn, level, &results, &result);
+        Status status = collection->validate(opCtx, level, &results, &result);
         if (!status.isOK())
             return appendCommandStatus(result, status);
 
diff --git a/src/mongo/db/commands/write_commands/write_commands.cpp b/src/mongo/db/commands/write_commands/write_commands.cpp
index 506709096b8..4093bcf083e 100644
--- a/src/mongo/db/commands/write_commands/write_commands.cpp
+++ b/src/mongo/db/commands/write_commands/write_commands.cpp
@@ -87,21 +87,21 @@ Status checkAuthForWriteCommand(Client* client,
     return status;
 }
 
-bool shouldSkipOutput(OperationContext* txn) {
-    const WriteConcernOptions& writeConcern = txn->getWriteConcern();
+bool shouldSkipOutput(OperationContext* opCtx) {
+    const WriteConcernOptions& writeConcern = opCtx->getWriteConcern();
     return writeConcern.wMode.empty() && writeConcern.wNumNodes == 0 &&
         (writeConcern.syncMode == WriteConcernOptions::SyncMode::NONE ||
          writeConcern.syncMode == WriteConcernOptions::SyncMode::UNSET);
 }
 
 enum class ReplyStyle { kUpdate, kNotUpdate };  // update has extra fields.
-void serializeReply(OperationContext* txn,
+void serializeReply(OperationContext* opCtx,
                     ReplyStyle replyStyle,
                     bool continueOnError,
                     size_t opsInBatch,
                     const WriteResult& result,
                     BSONObjBuilder* out) {
-    if (shouldSkipOutput(txn))
+    if (shouldSkipOutput(opCtx))
         return;
 
     long long n = 0;
@@ -170,10 +170,10 @@ void serializeReply(OperationContext* txn,
 
     {
         // Undocumented repl fields that mongos depends on.
-        auto* replCoord = repl::ReplicationCoordinator::get(txn->getServiceContext());
+        auto* replCoord = repl::ReplicationCoordinator::get(opCtx->getServiceContext());
         const auto replMode = replCoord->getReplicationMode();
         if (replMode != repl::ReplicationCoordinator::modeNone) {
-            const auto lastOp = repl::ReplClientInfo::forClient(txn->getClient()).getLastOp();
+            const auto lastOp = repl::ReplClientInfo::forClient(opCtx->getClient()).getLastOp();
             if (lastOp.getTerm() == repl::OpTime::kUninitializedTerm) {
                 out->append("opTime", lastOp.getTimestamp());
             } else {
@@ -207,22 +207,22 @@ public:
         return ReadWriteType::kWrite;
     }
 
-    bool run(OperationContext* txn,
+    bool run(OperationContext* opCtx,
              const std::string& dbname,
              BSONObj& cmdObj,
              int options,
              std::string& errmsg,
              BSONObjBuilder& result) final {
         try {
-            runImpl(txn, dbname, cmdObj, result);
+            runImpl(opCtx, dbname, cmdObj, result);
             return true;
         } catch (const DBException& ex) {
-            LastError::get(txn->getClient()).setLastError(ex.getCode(), ex.getInfo().msg);
+            LastError::get(opCtx->getClient()).setLastError(ex.getCode(), ex.getInfo().msg);
             throw;
         }
     }
 
-    virtual void runImpl(OperationContext* txn,
+    virtual void runImpl(OperationContext* opCtx,
                          const std::string& dbname,
                          const BSONObj& cmdObj,
                          BSONObjBuilder& result) = 0;
@@ -251,13 +251,13 @@ public:
                                         cmdObj);
     }
 
-    void runImpl(OperationContext* txn,
+    void runImpl(OperationContext* opCtx,
                  const std::string& dbname,
                  const BSONObj& cmdObj,
                  BSONObjBuilder& result) final {
         const auto batch = parseInsertCommand(dbname, cmdObj);
-        const auto reply = performInserts(txn, batch);
-        serializeReply(txn,
+        const auto reply = performInserts(opCtx, batch);
+        serializeReply(opCtx,
                        ReplyStyle::kNotUpdate,
                        batch.continueOnError,
                        batch.documents.size(),
@@ -287,17 +287,21 @@ public:
                                         cmdObj);
     }
 
-    void runImpl(OperationContext* txn,
+    void runImpl(OperationContext* opCtx,
                  const std::string& dbname,
                  const BSONObj& cmdObj,
                  BSONObjBuilder& result) final {
         const auto batch = parseUpdateCommand(dbname, cmdObj);
-        const auto reply = performUpdates(txn, batch);
-        serializeReply(
-            txn, ReplyStyle::kUpdate, batch.continueOnError, batch.updates.size(), reply, &result);
+        const auto reply = performUpdates(opCtx, batch);
+        serializeReply(opCtx,
+                       ReplyStyle::kUpdate,
+                       batch.continueOnError,
+                       batch.updates.size(),
+                       reply,
+                       &result);
     }
 
-    Status explain(OperationContext* txn,
+    Status explain(OperationContext* opCtx,
                    const std::string& dbname,
                    const BSONObj& cmdObj,
                    ExplainCommon::Verbosity verbosity,
@@ -319,16 +323,16 @@ public:
         updateRequest.setYieldPolicy(PlanExecutor::YIELD_AUTO);
         updateRequest.setExplain();
 
-        ParsedUpdate parsedUpdate(txn, &updateRequest);
+        ParsedUpdate parsedUpdate(opCtx, &updateRequest);
         uassertStatusOK(parsedUpdate.parseRequest());
 
         // Explains of write commands are read-only, but we take write locks so that timing
         // info is more accurate.
-        ScopedTransaction scopedXact(txn, MODE_IX);
-        AutoGetCollection collection(txn, batch.ns, MODE_IX);
+        ScopedTransaction scopedXact(opCtx, MODE_IX);
+        AutoGetCollection collection(opCtx, batch.ns, MODE_IX);
 
         auto exec = uassertStatusOK(getExecutorUpdate(
-            txn, &CurOp::get(txn)->debug(), collection.getCollection(), &parsedUpdate));
+            opCtx, &CurOp::get(opCtx)->debug(), collection.getCollection(), &parsedUpdate));
         Explain::explainStages(exec.get(), collection.getCollection(), verbosity, out);
         return Status::OK();
     }
@@ -355,13 +359,13 @@ public:
                                         cmdObj);
     }
 
-    void runImpl(OperationContext* txn,
+    void runImpl(OperationContext* opCtx,
                  const std::string& dbname,
                  const BSONObj& cmdObj,
                  BSONObjBuilder& result) final {
         const auto batch = parseDeleteCommand(dbname, cmdObj);
-        const auto reply = performDeletes(txn, batch);
-        serializeReply(txn,
+        const auto reply = performDeletes(opCtx, batch);
+        serializeReply(opCtx,
                        ReplyStyle::kNotUpdate,
                        batch.continueOnError,
                        batch.deletes.size(),
@@ -369,7 +373,7 @@ public:
                        &result);
     }
 
-    Status explain(OperationContext* txn,
+    Status explain(OperationContext* opCtx,
                    const std::string& dbname,
                    const BSONObj& cmdObj,
                    ExplainCommon::Verbosity verbosity,
@@ -387,17 +391,17 @@ public:
         deleteRequest.setYieldPolicy(PlanExecutor::YIELD_AUTO);
         deleteRequest.setExplain();
 
-        ParsedDelete parsedDelete(txn, &deleteRequest);
+        ParsedDelete parsedDelete(opCtx, &deleteRequest);
         uassertStatusOK(parsedDelete.parseRequest());
 
         // Explains of write commands are read-only, but we take write locks so that timing
         // info is more accurate.
-        ScopedTransaction scopedXact(txn, MODE_IX);
-        AutoGetCollection collection(txn, batch.ns, MODE_IX);
+        ScopedTransaction scopedXact(opCtx, MODE_IX);
+        AutoGetCollection collection(opCtx, batch.ns, MODE_IX);
 
         // Explain the plan tree.
         auto exec = uassertStatusOK(getExecutorDelete(
-            txn, &CurOp::get(txn)->debug(), collection.getCollection(), &parsedDelete));
+            opCtx, &CurOp::get(opCtx)->debug(), collection.getCollection(), &parsedDelete));
         Explain::explainStages(exec.get(), collection.getCollection(), verbosity, out);
         return Status::OK();
     }