SERVER-13641 Plumb OperationContext through to getCollection and all Helpers

93 files changed, 441 insertions, 422 deletions

diff --git a/src/mongo/db/auth/auth_index_d.cpp b/src/mongo/db/auth/auth_index_d.cpp
index b8ed201226e..07f692149fe 100644
--- a/src/mongo/db/auth/auth_index_d.cpp
+++ b/src/mongo/db/auth/auth_index_d.cpp
@@ -84,16 +84,16 @@ namespace {
             NamespaceString systemUsers(dbname, "system.users");
 
             // Make sure the old unique index from v2.4 on system.users doesn't exist.
-            OperationContextImpl txn;
-            Client::WriteContext wctx(&txn, systemUsers);
-            Collection* collection = wctx.ctx().db()->getCollection(NamespaceString(systemUsers));
+            Client::WriteContext wctx(txn, systemUsers);
+            Collection* collection = wctx.ctx().db()->getCollection(txn,
+                                                                    NamespaceString(systemUsers));
             if (!collection) {
                 return;
             }
             IndexCatalog* indexCatalog = collection->getIndexCatalog();
             IndexDescriptor* oldIndex = NULL;
             while ((oldIndex = indexCatalog->findIndexByKeyPattern(v1SystemUsersKeyPattern))) {
-                indexCatalog->dropIndex(&txn, oldIndex);
+                indexCatalog->dropIndex(txn, oldIndex);
             }
         }
     }
diff --git a/src/mongo/db/auth/authz_manager_external_state_d.cpp b/src/mongo/db/auth/authz_manager_external_state_d.cpp
index 852f6d96b71..0f80745769d 100644
--- a/src/mongo/db/auth/authz_manager_external_state_d.cpp
+++ b/src/mongo/db/auth/authz_manager_external_state_d.cpp
@@ -39,6 +39,7 @@
 #include "mongo/db/dbhelpers.h"
 #include "mongo/db/instance.h"
 #include "mongo/db/jsobj.h"
+#include "mongo/db/operation_context_impl.h"
 #include "mongo/util/assert_util.h"
 #include "mongo/util/mongoutils/str.h"
 
@@ -112,7 +113,8 @@ namespace mongo {
         Client::ReadContext ctx(txn, collectionName.ns());
 
         BSONObj found;
-        if (Helpers::findOne(ctx.ctx().db()->getCollection(collectionName),
+        if (Helpers::findOne(txn,
+                             ctx.ctx().db()->getCollection(txn, collectionName),
                              query,
                              found)) {
             *result = found.getOwned();
diff --git a/src/mongo/db/catalog/collection_cursor_cache.cpp b/src/mongo/db/catalog/collection_cursor_cache.cpp
index 766bb3cd4a0..dea303ed0e7 100644
--- a/src/mongo/db/catalog/collection_cursor_cache.cpp
+++ b/src/mongo/db/catalog/collection_cursor_cache.cpp
@@ -36,6 +36,7 @@
 #include "mongo/db/catalog/database.h"
 #include "mongo/db/catalog/database_holder.h"
 #include "mongo/db/client.h"
+#include "mongo/db/operation_context_impl.h"
 #include "mongo/db/query/runner.h"
 #include "mongo/platform/random.h"
 #include "mongo/util/startup_test.h"
@@ -191,7 +192,7 @@ namespace mongo {
         if ( !db )
             return false;
         Client::Context context( ns, db );
-        Collection* collection = db->getCollection( ns );
+        Collection* collection = db->getCollection( txn, ns );
         if ( !collection ) {
             if ( checkAuth )
                 audit::logKillCursorsAuthzCheck( currentClient.get(),
@@ -221,7 +222,7 @@ namespace mongo {
             if ( !db )
                 continue;
             Client::Context context( ns, db );
-            Collection* collection = db->getCollection( ns );
+            Collection* collection = db->getCollection( txn, ns );
             if ( collection == NULL ) {
                 continue;
             }
diff --git a/src/mongo/db/catalog/collection_cursor_cache.h b/src/mongo/db/catalog/collection_cursor_cache.h
index d08800d4d7b..c1f3647b021 100644
--- a/src/mongo/db/catalog/collection_cursor_cache.h
+++ b/src/mongo/db/catalog/collection_cursor_cache.h
@@ -39,6 +39,7 @@
 
 namespace mongo {
 
+    class OperationContext;
     class PseudoRandom;
     class Runner;
 
diff --git a/src/mongo/db/catalog/database.cpp b/src/mongo/db/catalog/database.cpp
index 969eda34e85..756b0871c75 100644
--- a/src/mongo/db/catalog/database.cpp
+++ b/src/mongo/db/catalog/database.cpp
@@ -233,7 +233,8 @@ namespace mongo {
         return true;
     }
 
-    long long Database::getIndexSizeForCollection(Collection* coll,
+    long long Database::getIndexSizeForCollection(OperationContext* opCtx,
+                                                  Collection* coll,
                                                   BSONObjBuilder* details,
                                                   int scale ) {
         if ( !coll )
@@ -247,7 +248,9 @@ namespace mongo {
         while ( ii.more() ) {
             IndexDescriptor* d = ii.next();
             string indNS = d->indexNamespace();
-            Collection* indColl = getCollection( indNS ); // XXX
+
+            // XXX creating a Collection for an index which isn't a Collection
+            Collection* indColl = getCollection( opCtx, indNS );
             if ( ! indColl ) {
                 log() << "error: have index descriptor ["  << indNS
                       << "] but no entry in the index collection." << endl;
@@ -262,7 +265,7 @@ namespace mongo {
         return totalSize;
     }
 
-    void Database::getStats( BSONObjBuilder* output, double scale ) {
+    void Database::getStats( OperationContext* opCtx, BSONObjBuilder* output, double scale ) {
         bool empty = isEmpty() || getExtentManager()->numFiles() == 0;
 
         list<string> collections;
@@ -280,7 +283,7 @@ namespace mongo {
         for (list<string>::const_iterator it = collections.begin(); it != collections.end(); ++it) {
             const string ns = *it;
 
-            Collection* collection = getCollection( ns );
+            Collection* collection = getCollection( opCtx, ns );
             if ( !collection )
                 continue;
 
@@ -293,7 +296,7 @@ namespace mongo {
             numExtents += temp.obj()["numExtents"].numberInt(); // XXX
 
             indexes += collection->getIndexCatalog()->numIndexesTotal();
-            indexSize += getIndexSizeForCollection(collection);
+            indexSize += getIndexSizeForCollection(opCtx, collection);
         }
 
         output->append      ( "db" , _name );
@@ -428,11 +431,6 @@ namespace mongo {
         _collections.erase( it );
     }
 
-    Collection* Database::getCollection( const StringData& ns ) {
-        OperationContextImpl txn; // TODO remove once we require reads to have transactions
-        return getCollection(&txn, ns);
-    }
-
     Collection* Database::getCollection( OperationContext* txn, const StringData& ns ) {
         invariant( _name == nsToDatabaseSubstring( ns ) );
 
@@ -489,7 +487,7 @@ namespace mongo {
 
         // move index namespaces
         BSONObj oldIndexSpec;
-        while (Helpers::findOne(systemIndexCollection, BSON("ns" << fromNS), oldIndexSpec)) {
+        while (Helpers::findOne(txn, systemIndexCollection, BSON("ns" << fromNS), oldIndexSpec)) {
             oldIndexSpec = oldIndexSpec.getOwned();
 
             BSONObj newIndexSpec;
@@ -597,7 +595,7 @@ namespace mongo {
         {
 
             BSONObj oldSpec;
-            if ( !Helpers::findOne( getCollection( txn, _namespacesName ),
+            if ( !Helpers::findOne( txn, getCollection( txn, _namespacesName ),
                                     BSON( "name" << fromNS ),
                                     oldSpec ) )
                 return Status( ErrorCodes::InternalError, "can't find system.namespaces entry" );
@@ -624,10 +622,6 @@ namespace mongo {
         return Status::OK();
     }
 
-    Collection* Database::getOrCreateCollection( const StringData& ns ) {
-        OperationContextImpl txn; // TODO remove once we require reads to have transactions
-        return getOrCreateCollection(&txn, ns);
-    }
     Collection* Database::getOrCreateCollection(OperationContext* txn, const StringData& ns) {
         Collection* c = getCollection( txn, ns );
         if ( !c ) {
@@ -641,7 +635,7 @@ namespace mongo {
                                             const CollectionOptions& options,
                                             bool allocateDefaultSpace,
                                             bool createIdIndex ) {
-        massert( 17399, "collection already exists", getCollection( ns ) == NULL );
+        massert( 17399, "collection already exists", getCollection( txn, ns ) == NULL );
         massertNamespaceNotIndex( ns, "createCollection" );
 
         if ( serverGlobalParams.configsvr &&
diff --git a/src/mongo/db/catalog/database.h b/src/mongo/db/catalog/database.h
index e3a0b37f28c..a54c8bd8364 100644
--- a/src/mongo/db/catalog/database.h
+++ b/src/mongo/db/catalog/database.h
@@ -105,9 +105,10 @@ namespace mongo {
         int getProfilingLevel() const { return _profile; }
         const char* getProfilingNS() const { return _profileName.c_str(); }
 
-        void getStats( BSONObjBuilder* output, double scale = 1 );
+        void getStats( OperationContext* opCtx, BSONObjBuilder* output, double scale = 1 );
 
-        long long getIndexSizeForCollection( Collection* collections,
+        long long getIndexSizeForCollection( OperationContext* opCtx,
+                                             Collection* collections,
                                              BSONObjBuilder* details = NULL,
                                              int scale = 1 );
 
@@ -127,20 +128,13 @@ namespace mongo {
 
         /**
          * @param ns - this is fully qualified, which is maybe not ideal ???
-         * The methods without a transaction are deprecated.
-         * TODO remove deprecated method once we require reads to have Transaction objects.
          */
-        Collection* getCollection( const StringData& ns );
-
-        Collection* getCollection( const NamespaceString& ns ) { return getCollection( ns.ns() ); }
-
         Collection* getCollection( OperationContext* txn, const StringData& ns );
 
         Collection* getCollection( OperationContext* txn, const NamespaceString& ns ) {
             return getCollection( txn, ns.ns() );
         }
 
-        Collection* getOrCreateCollection( const StringData& ns );
         Collection* getOrCreateCollection( OperationContext* txn, const StringData& ns );
 
         Status renameCollection( OperationContext* txn,
diff --git a/src/mongo/db/catalog/index_catalog.cpp b/src/mongo/db/catalog/index_catalog.cpp
index acef0995881..68559fc67ef 100644
--- a/src/mongo/db/catalog/index_catalog.cpp
+++ b/src/mongo/db/catalog/index_catalog.cpp
@@ -227,8 +227,9 @@ namespace mongo {
 
         fassert(16737, dfh->versionMinor == PDFILE_VERSION_MINOR_22_AND_OLDER);
 
-        auto_ptr<Runner> runner( InternalPlanner::collectionScan( db->_indexesName,
-                                                                  db->getCollection( db->_indexesName ) ) );
+        auto_ptr<Runner> runner(
+            InternalPlanner::collectionScan(db->_indexesName,
+                                            db->getCollection(txn, db->_indexesName)));
 
         BSONObj index;
         Runner::RunnerState state;
@@ -689,7 +690,7 @@ namespace mongo {
         long long numSystemIndexesEntries = 0;
         {
             Collection* systemIndexes =
-                _collection->_database->getCollection( _collection->_database->_indexesName );
+                _collection->_database->getCollection( txn, _collection->_database->_indexesName );
             if ( systemIndexes ) {
                 EqualityMatchExpression expr;
                 BSONObj nsBSON = BSON( "ns" << _collection->ns() );
diff --git a/src/mongo/db/cloner.cpp b/src/mongo/db/cloner.cpp
index 519a1f6b9e8..bf6d55cb3be 100644
--- a/src/mongo/db/cloner.cpp
+++ b/src/mongo/db/cloner.cpp
@@ -111,7 +111,7 @@ namespace mongo {
             Collection* collection = NULL;
 
             if ( isindex == false ) {
-                collection = context.db()->getCollection( to_collection );
+                collection = context.db()->getCollection( txn, to_collection );
                 if ( !collection ) {
                     massert( 17321,
                              str::stream()
@@ -491,7 +491,7 @@ namespace mongo {
                 bool old = inDBRepair;
                 try {
                     inDBRepair = true;
-                    Collection* c = context.db()->getCollection( to_name );
+                    Collection* c = context.db()->getCollection( txn, to_name );
                     if ( c )
                         c->getIndexCatalog()->ensureHaveIdIndex(txn);
                     inDBRepair = old;
diff --git a/src/mongo/db/commands.cpp b/src/mongo/db/commands.cpp
index 524a7f916de..ed487950309 100644
--- a/src/mongo/db/commands.cpp
+++ b/src/mongo/db/commands.cpp
@@ -196,7 +196,8 @@ namespace mongo {
         help << "no help defined";
     }
 
-    std::vector<BSONObj> Command::stopIndexBuilds(Database* db,
+    std::vector<BSONObj> Command::stopIndexBuilds(OperationContext* opCtx,
+                                                  Database* db,
                                                   const BSONObj& cmdObj) {
         return std::vector<BSONObj>();
     }
diff --git a/src/mongo/db/commands.h b/src/mongo/db/commands.h
index 4446020a94c..485deeb61e4 100644
--- a/src/mongo/db/commands.h
+++ b/src/mongo/db/commands.h
@@ -198,7 +198,8 @@ namespace mutablebson {
 
     public:
         // Stops all index builds required to run this command and returns index builds killed.
-        virtual std::vector<BSONObj> stopIndexBuilds(Database* db, 
+        virtual std::vector<BSONObj> stopIndexBuilds(OperationContext* opCtx,
+                                                     Database* db, 
                                                      const BSONObj& cmdObj);
 
         static const std::map<std::string,Command*>* commandsByBestName() { return _commandsByBestName; }
diff --git a/src/mongo/db/commands/collection_to_capped.cpp b/src/mongo/db/commands/collection_to_capped.cpp
index 0186a17b643..ceaaebefdcf 100644
--- a/src/mongo/db/commands/collection_to_capped.cpp
+++ b/src/mongo/db/commands/collection_to_capped.cpp
@@ -56,7 +56,7 @@ namespace mongo {
             return Status( ErrorCodes::NamespaceNotFound,
                            str::stream() << "source collection " << fromNs <<  " does not exist" );
 
-        if ( db->getCollection( toNs ) )
+        if ( db->getCollection( txn, toNs ) )
             return Status( ErrorCodes::NamespaceExists, "to collection already exists" );
 
         // create new collection
@@ -182,14 +182,15 @@ namespace mongo {
             out->push_back(Privilege(parseResourcePattern(dbname, cmdObj), actions));
         }
 
-        virtual std::vector<BSONObj> stopIndexBuilds(Database* db,
+        virtual std::vector<BSONObj> stopIndexBuilds(OperationContext* opCtx,
+                                                     Database* db,
                                                      const BSONObj& cmdObj) {
             std::string collName = cmdObj.firstElement().valuestr();
             std::string ns = db->name() + "." + collName;
 
             IndexCatalog::IndexKillCriteria criteria;
             criteria.ns = ns;
-            Collection* coll = db->getCollection(ns);
+            Collection* coll = db->getCollection(opCtx, ns);
             if (coll) {
                 return IndexBuilder::killMatchingIndexBuilds(coll, criteria);
             }
@@ -204,7 +205,7 @@ namespace mongo {
 
             Database* db = ctx.db();
 
-            stopIndexBuilds(db, jsobj);
+            stopIndexBuilds(txn, db, jsobj);
             BackgroundOperation::assertNoBgOpInProgForDb(dbname.c_str());
 
             string shortSource = jsobj.getStringField( "convertToCapped" );
@@ -219,7 +220,7 @@ namespace mongo {
             string shortTmpName = str::stream() << "tmp.convertToCapped." << shortSource;
             string longTmpName = str::stream() << dbname << "." << shortTmpName;
 
-            if ( db->getCollection( longTmpName ) ) {
+            if ( db->getCollection( txn, longTmpName ) ) {
                 Status status = db->dropCollection( txn, longTmpName );
                 if ( !status.isOK() )
                     return appendCommandStatus( result, status );
@@ -230,7 +231,7 @@ namespace mongo {
             if ( !status.isOK() )
                 return appendCommandStatus( result, status );
 
-            verify( db->getCollection( longTmpName ) );
+            verify( db->getCollection( txn, longTmpName ) );
 
             status = db->dropCollection( txn, longSource );
             if ( !status.isOK() )
diff --git a/src/mongo/db/commands/compact.cpp b/src/mongo/db/commands/compact.cpp
index 1002ec82ffd..d5e400e7c6b 100644
--- a/src/mongo/db/commands/compact.cpp
+++ b/src/mongo/db/commands/compact.cpp
@@ -71,14 +71,15 @@ namespace mongo {
         }
         CompactCmd() : Command("compact") { }
 
-        virtual std::vector<BSONObj> stopIndexBuilds(Database* db,
+        virtual std::vector<BSONObj> stopIndexBuilds(OperationContext* opCtx,
+                                                     Database* db,
                                                      const BSONObj& cmdObj) {
             std::string coll = cmdObj.firstElement().valuestr();
             std::string ns = db->name() + "." + coll;
 
             IndexCatalog::IndexKillCriteria criteria;
             criteria.ns = ns;
-            return IndexBuilder::killMatchingIndexBuilds(db->getCollection(ns), criteria);
+            return IndexBuilder::killMatchingIndexBuilds(db->getCollection(opCtx, ns), criteria);
         }
 
         virtual bool run(OperationContext* txn, const string& db, BSONObj& cmdObj, int, string& errmsg, BSONObjBuilder& result, bool fromRepl) {
@@ -144,7 +145,7 @@ namespace mongo {
             BackgroundOperation::assertNoBgOpInProgForNs(ns.ns());
             Client::Context ctx(ns);
 
-            Collection* collection = ctx.db()->getCollection(ns.ns());
+            Collection* collection = ctx.db()->getCollection(txn, ns.ns());
             if( ! collection ) {
                 errmsg = "namespace does not exist";
                 return false;
@@ -157,7 +158,7 @@ namespace mongo {
 
             log() << "compact " << ns << " begin, options: " << compactOptions.toString();
 
-            std::vector<BSONObj> indexesInProg = stopIndexBuilds(ctx.db(), cmdObj);
+            std::vector<BSONObj> indexesInProg = stopIndexBuilds(txn, ctx.db(), cmdObj);
 
             StatusWith<CompactStats> status = collection->compact( txn, &compactOptions );
             if ( !status.isOK() )
diff --git a/src/mongo/db/commands/create_indexes.cpp b/src/mongo/db/commands/create_indexes.cpp
index 841f9522ace..089bf040731 100644
--- a/src/mongo/db/commands/create_indexes.cpp
+++ b/src/mongo/db/commands/create_indexes.cpp
@@ -133,7 +133,7 @@ namespace mongo {
                 // lock for common calls. We only take write lock if needed.
                 // Note: createIndexes command does not currently respect shard versioning.
                 Client::ReadContext readContext(txn, ns, false /* doVersion */);
-                const Collection* collection = readContext.ctx().db()->getCollection( ns.ns() );
+                const Collection* collection = readContext.ctx().db()->getCollection(txn, ns.ns());
                 if ( collection ) {
                     for ( size_t i = 0; i < specs.size(); i++ ) {
                         BSONObj spec = specs[i];
diff --git a/src/mongo/db/commands/dbhash.cpp b/src/mongo/db/commands/dbhash.cpp
index 3899e7f522d..9b4a2a385aa 100644
--- a/src/mongo/db/commands/dbhash.cpp
+++ b/src/mongo/db/commands/dbhash.cpp
@@ -62,7 +62,7 @@ namespace mongo {
         out->push_back(Privilege(ResourcePattern::forDatabaseName(dbname), actions));
     }
 
-    string DBHashCmd::hashCollection( Database* db, const string& fullCollectionName, bool* fromCache ) {
+    string DBHashCmd::hashCollection( OperationContext* opCtx, Database* db, const string& fullCollectionName, bool* fromCache ) {
 
         scoped_ptr<scoped_lock> cachedHashedLock;
 
@@ -76,7 +76,7 @@ namespace mongo {
         }
 
         *fromCache = false;
-        Collection* collection = db->getCollection( fullCollectionName );
+        Collection* collection = db->getCollection( opCtx, fullCollectionName );
         if ( !collection )
             return "";
 
@@ -176,7 +176,7 @@ namespace mongo {
                 continue;
 
             bool fromCache = false;
-            string hash = hashCollection( db, fullCollectionName, &fromCache );
+            string hash = hashCollection( txn, db, fullCollectionName, &fromCache );
 
             bb.append( shortCollectionName, hash );
 
diff --git a/src/mongo/db/commands/dbhash.h b/src/mongo/db/commands/dbhash.h
index 71885f17697..383c7fb9d80 100644
--- a/src/mongo/db/commands/dbhash.h
+++ b/src/mongo/db/commands/dbhash.h
@@ -54,7 +54,7 @@ namespace mongo {
 
         bool isCachable( const StringData& ns ) const;
 
-        std::string hashCollection( Database* db, const std::string& fullCollectionName, bool* fromCache );
+        std::string hashCollection( OperationContext* opCtx, Database* db, const std::string& fullCollectionName, bool* fromCache );
 
         std::map<std::string,std::string> _cachedHashed;
         mutex _cachedHashedMutex;
diff --git a/src/mongo/db/commands/distinct.cpp b/src/mongo/db/commands/distinct.cpp
index 4c3a6bb5955..4f05700f65c 100644
--- a/src/mongo/db/commands/distinct.cpp
+++ b/src/mongo/db/commands/distinct.cpp
@@ -92,7 +92,7 @@ namespace mongo {
 
             Client::ReadContext ctx(txn, ns);
 
-            Collection* collection = ctx.ctx().db()->getCollection( ns );
+            Collection* collection = ctx.ctx().db()->getCollection( txn, ns );
 
             if (!collection) {
                 result.appendArray( "values" , BSONObj() );
diff --git a/src/mongo/db/commands/drop_indexes.cpp b/src/mongo/db/commands/drop_indexes.cpp
index c68aede5bc3..330e856e7db 100644
--- a/src/mongo/db/commands/drop_indexes.cpp
+++ b/src/mongo/db/commands/drop_indexes.cpp
@@ -61,10 +61,11 @@ namespace mongo {
             out->push_back(Privilege(parseResourcePattern(dbname, cmdObj), actions));
         }
 
-        virtual std::vector<BSONObj> stopIndexBuilds(Database* db, 
+        virtual std::vector<BSONObj> stopIndexBuilds(OperationContext* opCtx,
+                                                     Database* db, 
                                                      const BSONObj& cmdObj) {
             std::string toDeleteNs = db->name() + "." + cmdObj.firstElement().valuestr();
-            Collection* collection = db->getCollection(toDeleteNs);
+            Collection* collection = db->getCollection(opCtx, toDeleteNs);
             IndexCatalog::IndexKillCriteria criteria;
 
             // Get index name to drop
@@ -113,13 +114,13 @@ namespace mongo {
             Client::Context ctx(toDeleteNs);
             Database* db = ctx.db();
 
-            Collection* collection = db->getCollection( toDeleteNs );
+            Collection* collection = db->getCollection( txn, toDeleteNs );
             if ( ! collection ) {
                 errmsg = "ns not found";
                 return false;
             }
 
-            stopIndexBuilds(db, jsobj);
+            stopIndexBuilds(txn, db, jsobj);
 
             IndexCatalog* indexCatalog = collection->getIndexCatalog();
             anObjBuilder.appendNumber("nIndexesWas", indexCatalog->numIndexesTotal() );
@@ -204,12 +205,13 @@ namespace mongo {
         }
         CmdReIndex() : Command("reIndex") { }
 
-        virtual std::vector<BSONObj> stopIndexBuilds(Database* db,
+        virtual std::vector<BSONObj> stopIndexBuilds(OperationContext* opCtx,
+                                                     Database* db,
                                                      const BSONObj& cmdObj) {
             std::string ns = db->name() + '.' + cmdObj["reIndex"].valuestrsafe();
             IndexCatalog::IndexKillCriteria criteria;
             criteria.ns = ns;
-            return IndexBuilder::killMatchingIndexBuilds(db->getCollection(ns), criteria);
+            return IndexBuilder::killMatchingIndexBuilds(db->getCollection(opCtx, ns), criteria);
         }
 
         bool run(OperationContext* txn, const string& dbname , BSONObj& jsobj, int, string& errmsg, BSONObjBuilder& result, bool /*fromRepl*/) {
@@ -223,7 +225,7 @@ namespace mongo {
             Lock::DBWrite dbXLock(txn->lockState(), dbname);
             Client::Context ctx(toDeleteNs);
 
-            Collection* collection = ctx.db()->getCollection( toDeleteNs );
+            Collection* collection = ctx.db()->getCollection( txn, toDeleteNs );
 
             if ( !collection ) {
                 errmsg = "ns not found";
@@ -232,7 +234,7 @@ namespace mongo {
 
             BackgroundOperation::assertNoBgOpInProgForNs( toDeleteNs );
 
-            std::vector<BSONObj> indexesInProg = stopIndexBuilds(ctx.db(), jsobj);
+            std::vector<BSONObj> indexesInProg = stopIndexBuilds(txn, ctx.db(), jsobj);
 
             list<BSONObj> all;
             auto_ptr<DBClientCursor> i = db.query( dbname + ".system.indexes" , BSON( "ns" << toDeleteNs ) , 0 , 0 , 0 , QueryOption_SlaveOk );
diff --git a/src/mongo/db/commands/find_and_modify.cpp b/src/mongo/db/commands/find_and_modify.cpp
index 37d777b2da3..fe283804073 100644
--- a/src/mongo/db/commands/find_and_modify.cpp
+++ b/src/mongo/db/commands/find_and_modify.cpp
@@ -255,7 +255,7 @@ namespace mongo {
                     UpdateResult res = mongo::update(txn, cx.db(), request, &cc().curop()->debug());
                     if ( !collection ) {
                         // collection created by an upsert
-                        collection = cx.db()->getCollection( ns );
+                        collection = cx.db()->getCollection( txn, ns );
                     }
 
                     LOG(3) << "update result: "  << res ;
@@ -272,7 +272,7 @@ namespace mongo {
                         }
 
                         LOG(3) << "using modified query to return the new doc: " << queryModified;
-                        if ( ! Helpers::findOne( collection, queryModified, doc ) ) {
+                        if ( ! Helpers::findOne( txn, collection, queryModified, doc ) ) {
                             errmsg = str::stream() << "can't find object after modification  " 
                                                    << " ns: " << ns 
                                                    << " queryModified: " << queryModified 
diff --git a/src/mongo/db/commands/geonear.cpp b/src/mongo/db/commands/geonear.cpp
index ebbdd6efd69..42a956bf862 100644
--- a/src/mongo/db/commands/geonear.cpp
+++ b/src/mongo/db/commands/geonear.cpp
@@ -84,7 +84,7 @@ namespace mongo {
                 return false;
             }
 
-            Collection* collection = db->getCollection( ns );
+            Collection* collection = db->getCollection( txn, ns );
             if ( !collection ) {
                 errmsg = "can't find ns";
                 return false;
diff --git a/src/mongo/db/commands/group.cpp b/src/mongo/db/commands/group.cpp
index 94920e4d61e..b65f4f85fcd 100644
--- a/src/mongo/db/commands/group.cpp
+++ b/src/mongo/db/commands/group.cpp
@@ -87,7 +87,8 @@ namespace mongo {
             return obj.extractFields( keyPattern , true ).getOwned();
         }
 
-        bool group( Database* db,
+        bool group( OperationContext* txn,
+                    Database* db,
                     const std::string& ns,
                     const BSONObj& query,
                     BSONObj keyPattern,
@@ -131,7 +132,7 @@ namespace mongo {
             double keysize = keyPattern.objsize() * 3;
             double keynum = 1;
 
-            Collection* collection = db->getCollection( ns );
+            Collection* collection = db->getCollection( txn, ns );
 
             const WhereCallbackReal whereCallback(StringData(db->name()));
 
@@ -256,7 +257,7 @@ namespace mongo {
             const string ns = parseNs(dbname, jsobj);
             Client::ReadContext ctx(txn, ns);
 
-            return group( ctx.ctx().db() , ns , q ,
+            return group( txn, ctx.ctx().db() , ns , q ,
                           key , keyf , reduce._asCode() , reduce.type() != CodeWScope ? 0 : reduce.codeWScopeScopeDataUnsafe() ,
                           initial.embeddedObject() , finalize ,
                           errmsg , result );
diff --git a/src/mongo/db/commands/index_filter_commands.cpp b/src/mongo/db/commands/index_filter_commands.cpp
index efc92edd3a3..b07d6086c35 100644
--- a/src/mongo/db/commands/index_filter_commands.cpp
+++ b/src/mongo/db/commands/index_filter_commands.cpp
@@ -65,12 +65,12 @@ namespace {
     /**
      * Retrieves a collection's query settings and plan cache from the database.
      */
-    Status getQuerySettingsAndPlanCache(Database* db, const string& ns,
+    Status getQuerySettingsAndPlanCache(OperationContext* txn, Database* db, const string& ns,
                                         QuerySettings** querySettingsOut,
                                         PlanCache** planCacheOut) {
         invariant(db);
 
-        Collection* collection = db->getCollection(ns);
+        Collection* collection = db->getCollection(txn, ns);
         if (NULL == collection) {
             return Status(ErrorCodes::BadValue, "no such collection");
         }
@@ -169,7 +169,7 @@ namespace mongo {
         Client::Context& ctx = readCtx.ctx();
         QuerySettings* querySettings;
         PlanCache* unused;
-        Status status = getQuerySettingsAndPlanCache(ctx.db(), ns, &querySettings, &unused);
+        Status status = getQuerySettingsAndPlanCache(txn, ctx.db(), ns, &querySettings, &unused);
         if (!status.isOK()) {
             // No collection - return empty array of filters.
             BSONArrayBuilder hintsBuilder(bob->subarrayStart("filters"));
@@ -231,7 +231,7 @@ namespace mongo {
         Client::Context& ctx = readCtx.ctx();
         QuerySettings* querySettings;
         PlanCache* planCache;
-        Status status = getQuerySettingsAndPlanCache(ctx.db(), ns, &querySettings, &planCache);
+        Status status = getQuerySettingsAndPlanCache(txn, ctx.db(), ns, &querySettings, &planCache);
         if (!status.isOK()) {
             // No collection - do nothing.
             return Status::OK();
@@ -322,7 +322,7 @@ namespace mongo {
         Client::Context& ctx = readCtx.ctx();
         QuerySettings* querySettings;
         PlanCache* planCache;
-        Status status = getQuerySettingsAndPlanCache(ctx.db(), ns, &querySettings, &planCache);
+        Status status = getQuerySettingsAndPlanCache(txn, ctx.db(), ns, &querySettings, &planCache);
         if (!status.isOK()) {
             return status;
         }
diff --git a/src/mongo/db/commands/mr.cpp b/src/mongo/db/commands/mr.cpp
index 97c5d1fb9b5..53368a50cf7 100644
--- a/src/mongo/db/commands/mr.cpp
+++ b/src/mongo/db/commands/mr.cpp
@@ -366,7 +366,7 @@ namespace mongo {
                 // copy indexes into temporary storage
                 Client::WriteContext finalCtx(_txn, _config.outputOptions.finalNamespace);
                 Collection* finalColl =
-                    finalCtx.ctx().db()->getCollection( _config.outputOptions.finalNamespace );
+                    finalCtx.ctx().db()->getCollection(_txn, _config.outputOptions.finalNamespace);
                 if ( finalColl ) {
                     IndexCatalog::IndexIterator ii =
                         finalColl->getIndexCatalog()->getIndexIterator( true );
@@ -584,8 +584,10 @@ namespace mongo {
                     bool found;
                     {
                         Client::Context tx( _config.outputOptions.finalNamespace );
-                        Collection* coll = tx.db()->getCollection( _config.outputOptions.finalNamespace );
-                        found = Helpers::findOne(coll,
+                        Collection* coll =
+                            tx.db()->getCollection(_txn, _config.outputOptions.finalNamespace);
+                        found = Helpers::findOne(_txn,
+                                                 coll,
                                                  temp["_id"].wrap(),
                                                  old,
                                                  true);
@@ -620,7 +622,7 @@ namespace mongo {
             verify( _onDisk );
 
             Client::WriteContext ctx(_txn,  ns );
-            Collection* coll = ctx.ctx().db()->getCollection( ns );
+            Collection* coll = ctx.ctx().db()->getCollection( _txn, ns );
             if ( !coll )
                 uasserted(13630, str::stream() << "attempted to insert into nonexistent" <<
                                                   " collection during a mr operation." <<
@@ -646,7 +648,7 @@ namespace mongo {
             verify( _onDisk );
 
             Client::WriteContext ctx(_txn,  _config.incLong );
-            Collection* coll = ctx.ctx().db()->getCollection( _config.incLong );
+            Collection* coll = ctx.ctx().db()->getCollection( _txn, _config.incLong );
             if ( !coll )
                 uasserted(13631, str::stream() << "attempted to insert into nonexistent"
                                                   " collection during a mr operation." <<
@@ -922,7 +924,7 @@ namespace mongo {
 
             {
                 Client::WriteContext incCtx(_txn, _config.incLong );
-                Collection* incColl = incCtx.ctx().db()->getCollection( _config.incLong );
+                Collection* incColl = incCtx.ctx().db()->getCollection( _txn, _config.incLong );
 
                 bool foundIndex = false;
                 IndexCatalog::IndexIterator ii =
@@ -961,7 +963,7 @@ namespace mongo {
                                                 whereCallback).isOK());
 
             Runner* rawRunner;
-            verify(getRunner(ctx->ctx().db()->getCollection(_config.incLong),
+            verify(getRunner(ctx->ctx().db()->getCollection(_txn, _config.incLong),
                              cq, &rawRunner, QueryPlannerParams::NO_TABLE_SCAN).isOK());
 
             auto_ptr<Runner> runner(rawRunner);
@@ -1217,7 +1219,7 @@ namespace mongo {
                 auto_ptr<RangePreserver> rangePreserver;
                 {
                     Client::ReadContext ctx(txn, config.ns);
-                    Collection* collection = ctx.ctx().db()->getCollection( config.ns );
+                    Collection* collection = ctx.ctx().db()->getCollection( txn, config.ns );
                     if ( collection )
                         rangePreserver.reset(new RangePreserver(collection));
 
@@ -1299,7 +1301,7 @@ namespace mongo {
                         }
 
                         Runner* rawRunner;
-                        if (!getRunner(ctx->db()->getCollection( config.ns), cq, &rawRunner).isOK()) {
+                        if (!getRunner(ctx->db()->getCollection(txn, config.ns), cq, &rawRunner).isOK()) {
                             uasserted(17239, "Can't get runner for query " + config.filter.toString());
                             return 0;
                         }
diff --git a/src/mongo/db/commands/parallel_collection_scan.cpp b/src/mongo/db/commands/parallel_collection_scan.cpp
index 593912cf0d4..4f41daa71f1 100644
--- a/src/mongo/db/commands/parallel_collection_scan.cpp
+++ b/src/mongo/db/commands/parallel_collection_scan.cpp
@@ -168,7 +168,7 @@ namespace mongo {
             Client::ReadContext ctx(txn, ns.ns());
 
             Database* db = ctx.ctx().db();
-            Collection* collection = db->getCollection( ns );
+            Collection* collection = db->getCollection( txn, ns );
 
             if ( !collection )
                 return appendCommandStatus( result,
diff --git a/src/mongo/db/commands/pipeline_command.cpp b/src/mongo/db/commands/pipeline_command.cpp
index a43d77eeda0..4e40b49287c 100644
--- a/src/mongo/db/commands/pipeline_command.cpp
+++ b/src/mongo/db/commands/pipeline_command.cpp
@@ -319,7 +319,7 @@ namespace {
                 // on ShardFilterStage for more details.
                 Client::ReadContext ctx(txn, ns);
 
-                Collection* collection = ctx.ctx().db()->getCollection(ns);
+                Collection* collection = ctx.ctx().db()->getCollection(txn, ns);
 
                 // This does mongod-specific stuff like creating the input Runner and adding to the
                 // front of the pipeline if needed.
diff --git a/src/mongo/db/commands/plan_cache_commands.cpp b/src/mongo/db/commands/plan_cache_commands.cpp
index a8d32641646..cd572562f58 100644
--- a/src/mongo/db/commands/plan_cache_commands.cpp
+++ b/src/mongo/db/commands/plan_cache_commands.cpp
@@ -62,10 +62,10 @@ namespace {
     /**
      * Retrieves a collection's plan cache from the database.
      */
-    Status getPlanCache(Database* db, const string& ns, PlanCache** planCacheOut) {
+    Status getPlanCache(OperationContext* txn, Database* db, const string& ns, PlanCache** planCacheOut) {
         invariant(db);
 
-        Collection* collection = db->getCollection(ns);
+        Collection* collection = db->getCollection(txn, ns);
         if (NULL == collection) {
             return Status(ErrorCodes::BadValue, "no such collection");
         }
@@ -215,7 +215,7 @@ namespace mongo {
         Client::ReadContext readCtx(txn, ns);
         Client::Context& ctx = readCtx.ctx();
         PlanCache* planCache;
-        Status status = getPlanCache(ctx.db(), ns, &planCache);
+        Status status = getPlanCache(txn, ctx.db(), ns, &planCache);
         if (!status.isOK()) {
             // No collection - return results with empty shapes array.
             BSONArrayBuilder arrayBuilder(bob->subarrayStart("shapes"));
@@ -263,7 +263,7 @@ namespace mongo {
         Client::ReadContext readCtx(txn, ns);
         Client::Context& ctx = readCtx.ctx();
         PlanCache* planCache;
-        Status status = getPlanCache(ctx.db(), ns, &planCache);
+        Status status = getPlanCache(txn, ctx.db(), ns, &planCache);
         if (!status.isOK()) {
             // No collection - nothing to do. Return OK status.
             return Status::OK();
@@ -334,7 +334,7 @@ namespace mongo {
         Client::ReadContext readCtx(txn, ns);
         Client::Context& ctx = readCtx.ctx();
         PlanCache* planCache;
-        Status status = getPlanCache(ctx.db(), ns, &planCache);
+        Status status = getPlanCache(txn, ctx.db(), ns, &planCache);
         if (!status.isOK()) {
             // No collection - return empty plans array.
             BSONArrayBuilder plansBuilder(bob->subarrayStart("plans"));
diff --git a/src/mongo/db/commands/rename_collection.cpp b/src/mongo/db/commands/rename_collection.cpp
index 851b783aa99..1b9e61339b9 100644
--- a/src/mongo/db/commands/rename_collection.cpp
+++ b/src/mongo/db/commands/rename_collection.cpp
@@ -63,7 +63,8 @@ namespace mongo {
             help << " example: { renameCollection: foo.a, to: bar.b }";
         }
 
-        virtual std::vector<BSONObj> stopIndexBuilds(Database* db,
+        virtual std::vector<BSONObj> stopIndexBuilds(OperationContext* opCtx,
+                                                     Database* db,
                                                      const BSONObj& cmdObj) {
             string source = cmdObj.getStringField( name.c_str() );
             string target = cmdObj.getStringField( "to" );
@@ -71,7 +72,7 @@ namespace mongo {
             IndexCatalog::IndexKillCriteria criteria;
             criteria.ns = source;
             std::vector<BSONObj> prelim = 
-                IndexBuilder::killMatchingIndexBuilds(db->getCollection(source), criteria);
+                IndexBuilder::killMatchingIndexBuilds(db->getCollection(opCtx, source), criteria);
 
             std::vector<BSONObj> indexes;
 
@@ -139,7 +140,7 @@ namespace mongo {
 
             {
                 Client::Context srcCtx( source );
-                Collection* sourceColl = srcCtx.db()->getCollection( source );
+                Collection* sourceColl = srcCtx.db()->getCollection( txn, source );
 
                 if ( !sourceColl ) {
                     errmsg = "source namespace does not exist";
@@ -172,7 +173,7 @@ namespace mongo {
 
                 {
 
-                    indexesInProg = stopIndexBuilds( srcCtx.db(), cmdObj );
+                    indexesInProg = stopIndexBuilds( txn, srcCtx.db(), cmdObj );
                     capped = sourceColl->isCapped();
                     if ( capped ) {
                         size = sourceColl->getRecordStore()->storageSize();
@@ -185,7 +186,7 @@ namespace mongo {
 
                 // Check if the target namespace exists and if dropTarget is true.
                 // If target exists and dropTarget is not true, return false.
-                if ( ctx.db()->getCollection( target ) ) {
+                if ( ctx.db()->getCollection( txn, target ) ) {
                     if ( !cmdObj["dropTarget"].trueValue() ) {
                         errmsg = "target namespace exists";
                         return false;
@@ -245,7 +246,7 @@ namespace mongo {
 
             {
                 Client::Context srcCtx( source );
-                sourceColl = srcCtx.db()->getCollection( source );
+                sourceColl = srcCtx.db()->getCollection( txn, source );
                 sourceIt.reset( sourceColl->getIterator( DiskLoc(), false, CollectionScanParams::FORWARD ) );
             }
 
@@ -260,7 +261,7 @@ namespace mongo {
                 {
                     Client::Context ctx( target );
                     if ( !targetColl )
-                        targetColl = ctx.db()->getCollection( target );
+                        targetColl = ctx.db()->getCollection( txn, target );
                     // No logOp necessary because the entire renameCollection command is one logOp.
                     Status s = targetColl->insertDocument( txn, o, true ).getStatus();
                     if ( !s.isOK() ) {
@@ -314,7 +315,7 @@ namespace mongo {
             {
                 Client::Context ctx( target );
                 if ( !targetColl )
-                    targetColl = ctx.db()->getCollection( target );
+                    targetColl = ctx.db()->getCollection( txn, target );
 
                 for ( vector<BSONObj>::iterator it = copiedIndexes.begin();
                                                 it != copiedIndexes.end(); ++it ) {
diff --git a/src/mongo/db/commands/test_commands.cpp b/src/mongo/db/commands/test_commands.cpp
index 7265270beef..f3ba8efe67c 100644
--- a/src/mongo/db/commands/test_commands.cpp
+++ b/src/mongo/db/commands/test_commands.cpp
@@ -65,7 +65,7 @@ namespace mongo {
             Lock::DBWrite lk(txn->lockState(), ns);
             Client::Context ctx( ns );
             Database* db = ctx.db();
-            Collection* collection = db->getCollection( ns );
+            Collection* collection = db->getCollection( txn, ns );
             if ( !collection ) {
                 collection = db->createCollection( txn, ns );
                 if ( !collection ) {
@@ -141,7 +141,7 @@ namespace mongo {
             bool inc = cmdObj.getBoolField( "inc" ); // inclusive range?
 
             Client::WriteContext ctx(txn,  nss.ns() );
-            Collection* collection = ctx.ctx().db()->getCollection( nss.ns() );
+            Collection* collection = ctx.ctx().db()->getCollection( txn, nss.ns() );
             massert( 13417, "captrunc collection not found or empty", collection);
 
             boost::scoped_ptr<Runner> runner(InternalPlanner::collectionScan(nss.ns(),
@@ -170,14 +170,15 @@ namespace mongo {
                                            const BSONObj& cmdObj,
                                            std::vector<Privilege>* out) {}
 
-        virtual std::vector<BSONObj> stopIndexBuilds(Database* db, 
+        virtual std::vector<BSONObj> stopIndexBuilds(OperationContext* opCtx,
+                                                     Database* db, 
                                                      const BSONObj& cmdObj) {
             std::string coll = cmdObj[ "emptycapped" ].valuestrsafe();
             std::string ns = db->name() + '.' + coll;
 
             IndexCatalog::IndexKillCriteria criteria;
             criteria.ns = ns;
-            return IndexBuilder::killMatchingIndexBuilds(db->getCollection(ns), criteria);
+            return IndexBuilder::killMatchingIndexBuilds(db->getCollection(opCtx, ns), criteria);
         }
 
         virtual bool run(OperationContext* txn, const string& dbname , BSONObj& cmdObj, int, string& errmsg, BSONObjBuilder& result, bool fromRepl) {
@@ -187,10 +188,10 @@ namespace mongo {
 
             Client::WriteContext ctx(txn,  nss.ns() );
             Database* db = ctx.ctx().db();
-            Collection* collection = db->getCollection( nss.ns() );
+            Collection* collection = db->getCollection( txn, nss.ns() );
             massert( 13429, "emptycapped no such collection", collection );
 
-            std::vector<BSONObj> indexes = stopIndexBuilds(db, cmdObj);
+            std::vector<BSONObj> indexes = stopIndexBuilds(txn, db, cmdObj);
 
             Status status = collection->truncate(txn);
             if ( !status.isOK() )
diff --git a/src/mongo/db/commands/touch.cpp b/src/mongo/db/commands/touch.cpp
index ec2fc972659..e7f2c7eeef2 100644
--- a/src/mongo/db/commands/touch.cpp
+++ b/src/mongo/db/commands/touch.cpp
@@ -107,7 +107,7 @@ namespace mongo {
             Client::ReadContext context(txn, nss.ns());
 
             Database* db = context.ctx().db();
-            Collection* collection = db->getCollection( nss.ns() );
+            Collection* collection = db->getCollection( txn, nss.ns() );
             if ( !collection ) {
                 errmsg = "collection not found";
                 return false;
diff --git a/src/mongo/db/commands/validate.cpp b/src/mongo/db/commands/validate.cpp
index 9b539a8b954..7e69e6315c4 100644
--- a/src/mongo/db/commands/validate.cpp
+++ b/src/mongo/db/commands/validate.cpp
@@ -83,7 +83,7 @@ namespace mongo {
                 return false;
             }
 
-            Collection* collection = db->getCollection( ns );
+            Collection* collection = db->getCollection( txn, ns );
             if ( !collection ) {
                 errmsg = "collection not found";
                 return false;
diff --git a/src/mongo/db/commands/write_commands/batch_executor.cpp b/src/mongo/db/commands/write_commands/batch_executor.cpp
index b147446a93d..71d5d4538bd 100644
--- a/src/mongo/db/commands/write_commands/batch_executor.cpp
+++ b/src/mongo/db/commands/write_commands/batch_executor.cpp
@@ -917,7 +917,7 @@ namespace mongo {
                                            false /* don't check version */));
         Database* database = _context->db();
         dassert(database);
-        _collection = database->getCollection(request->getTargetingNS());
+        _collection = database->getCollection(txn, request->getTargetingNS());
         if (!_collection) {
             // Implicitly create if it doesn't exist
             _collection = database->createCollection(txn, request->getTargetingNS());
diff --git a/src/mongo/db/db.cpp b/src/mongo/db/db.cpp
index 93408e92a23..c4fb3221ff5 100644
--- a/src/mongo/db/db.cpp
+++ b/src/mongo/db/db.cpp
@@ -320,7 +320,7 @@ namespace mongo {
         fassert( 17401, repairDatabase( &txn, dbName ) );
     }
 
-    void checkForIdIndexes( Database* db ) {
+    void checkForIdIndexes( OperationContext* txn, Database* db ) {
 
         if ( db->name() == "local") {
             // we do not need an _id index on anything in the local database
@@ -337,7 +337,7 @@ namespace mongo {
             if ( ns.isSystem() )
                 continue;
 
-            Collection* coll = db->getCollection( collectionName );
+            Collection* coll = db->getCollection( txn, collectionName );
             if ( !coll )
                 continue;
 
@@ -373,7 +373,7 @@ namespace mongo {
 
             if (repl::replSettings.usingReplSets()) {
                 // we only care about the _id index if we are in a replset
-                checkForIdIndexes(ctx.db());
+                checkForIdIndexes(&txn, ctx.db());
             }
 
             if (shouldClearNonLocalTmpCollections || dbName == "local")
@@ -412,7 +412,7 @@ namespace mongo {
             }
             else {
                 const string systemIndexes = ctx.db()->name() + ".system.indexes";
-                Collection* coll = ctx.db()->getCollection( systemIndexes );
+                Collection* coll = ctx.db()->getCollection( &txn, systemIndexes );
                 auto_ptr<Runner> runner(InternalPlanner::collectionScan(systemIndexes,coll));
                 BSONObj index;
                 Runner::RunnerState state;
diff --git a/src/mongo/db/dbcommands.cpp b/src/mongo/db/dbcommands.cpp
index e751dbaeebb..a202667d7d4 100644
--- a/src/mongo/db/dbcommands.cpp
+++ b/src/mongo/db/dbcommands.cpp
@@ -164,7 +164,8 @@ namespace mongo {
 
         virtual bool isWriteCommandForConfigServer() const { return true; }
 
-        virtual std::vector<BSONObj> stopIndexBuilds(Database* db, 
+        virtual std::vector<BSONObj> stopIndexBuilds(OperationContext* opCtx,
+                                                     Database* db, 
                                                      const BSONObj& cmdObj) {
             invariant(db);
             std::list<std::string> collections;
@@ -179,7 +180,7 @@ namespace mongo {
                 IndexCatalog::IndexKillCriteria criteria;
                 criteria.ns = ns;
                 std::vector<BSONObj> killedIndexes = 
-                    IndexBuilder::killMatchingIndexBuilds(db->getCollection(ns), criteria);
+                    IndexBuilder::killMatchingIndexBuilds(db->getCollection(opCtx, ns), criteria);
                 allKilledIndexes.insert(allKilledIndexes.end(), 
                                         killedIndexes.begin(), 
                                         killedIndexes.end());
@@ -211,7 +212,7 @@ namespace mongo {
 
                 log() << "dropDatabase " << dbname << " starting" << endl;
 
-                stopIndexBuilds(context.db(), cmdObj);
+                stopIndexBuilds(txn, context.db(), cmdObj);
                 dropDatabase(txn, context.db());
 
                 log() << "dropDatabase " << dbname << " finished";
@@ -250,7 +251,8 @@ namespace mongo {
 
         }
 
-        virtual std::vector<BSONObj> stopIndexBuilds(Database* db, 
+        virtual std::vector<BSONObj> stopIndexBuilds(OperationContext* opCtx,
+                                                     Database* db, 
                                                      const BSONObj& cmdObj) {
             invariant(db);
             std::list<std::string> collections;
@@ -265,7 +267,7 @@ namespace mongo {
                 IndexCatalog::IndexKillCriteria criteria;
                 criteria.ns = ns;
                 std::vector<BSONObj> killedIndexes = 
-                    IndexBuilder::killMatchingIndexBuilds(db->getCollection(ns), criteria);
+                    IndexBuilder::killMatchingIndexBuilds(db->getCollection(opCtx, ns), criteria);
                 allKilledIndexes.insert(allKilledIndexes.end(), 
                                         killedIndexes.begin(), 
                                         killedIndexes.end());
@@ -286,7 +288,7 @@ namespace mongo {
             Client::Context context( dbname );
 
             log() << "repairDatabase " << dbname;
-            std::vector<BSONObj> indexesInProg = stopIndexBuilds(context.db(), cmdObj);
+            std::vector<BSONObj> indexesInProg = stopIndexBuilds(txn, context.db(), cmdObj);
 
             e = cmdObj.getField( "preserveClonedFilesOnFailure" );
             bool preserveClonedFilesOnFailure = e.isBoolean() && e.boolean();
@@ -437,13 +439,14 @@ namespace mongo {
 
         virtual bool isWriteCommandForConfigServer() const { return true; }
 
-        virtual std::vector<BSONObj> stopIndexBuilds(Database* db, 
+        virtual std::vector<BSONObj> stopIndexBuilds(OperationContext* opCtx,
+                                                     Database* db, 
                                                      const BSONObj& cmdObj) {
             std::string nsToDrop = db->name() + '.' + cmdObj.firstElement().valuestr();
 
             IndexCatalog::IndexKillCriteria criteria;
             criteria.ns = nsToDrop;
-            return IndexBuilder::killMatchingIndexBuilds(db->getCollection(nsToDrop), criteria);
+            return IndexBuilder::killMatchingIndexBuilds(db->getCollection(opCtx, nsToDrop), criteria);
         }
 
         virtual bool run(OperationContext* txn, const string& dbname , BSONObj& cmdObj, int, string& errmsg, BSONObjBuilder& result, bool fromRepl) {
@@ -470,7 +473,7 @@ namespace mongo {
 
             int numIndexes = coll->getIndexCatalog()->numIndexesTotal();
 
-            stopIndexBuilds(db, cmdObj);
+            stopIndexBuilds(txn, db, cmdObj);
 
             result.append( "ns", nsToDrop );
             result.append( "nIndexesWas", numIndexes );
@@ -532,7 +535,7 @@ namespace mongo {
 
             string err;
             int errCode;
-            long long n = runCount(ns, cmdObj, err, errCode);
+            long long n = runCount(txn, ns, cmdObj, err, errCode);
 
             long long retVal = n;
             bool ok = true;
@@ -813,7 +816,7 @@ namespace mongo {
             // Check shard version at startup.
             // This will throw before we've done any work if shard version is outdated
             Client::ReadContext ctx(txn, ns);
-            Collection* coll = ctx.ctx().db()->getCollection(ns);
+            Collection* coll = ctx.ctx().db()->getCollection(txn, ns);
 
             CanonicalQuery* cq;
             if (!CanonicalQuery::canonicalize(ns, query, sort, BSONObj(), &cq).isOK()) {
@@ -922,7 +925,7 @@ namespace mongo {
 
             Client::ReadContext ctx(txn, ns);
 
-            Collection* collection = ctx.ctx().db()->getCollection( ns );
+            Collection* collection = ctx.ctx().db()->getCollection( txn, ns );
 
             if ( !collection || collection->numRecords() == 0 ) {
                 result.appendNumber( "size" , 0 );
@@ -1039,7 +1042,7 @@ namespace mongo {
             const string ns = dbname + "." + jsobj.firstElement().valuestr();
             Client::ReadContext cx(txn, ns);
             Database* db = cx.ctx().db();
-            Collection* collection = db->getCollection( ns );
+            Collection* collection = db->getCollection( txn, ns );
             if ( !collection ) {
                 errmsg = "Collection [" + ns + "] not found.";
                 return false;
@@ -1078,7 +1081,8 @@ namespace mongo {
             collection->getRecordStore()->appendCustomStats( &result, scale );
 
             BSONObjBuilder indexSizes;
-            result.appendNumber( "totalIndexSize" , db->getIndexSizeForCollection(collection,
+            result.appendNumber( "totalIndexSize" , db->getIndexSizeForCollection(txn,
+                                                                                  collection,
                                                                                   &indexSizes,
                                                                                   scale) / scale );
             result.append("indexSizes", indexSizes.obj());
@@ -1117,7 +1121,7 @@ namespace mongo {
             Lock::DBWrite dbXLock(txn->lockState(), dbname);
             Client::Context ctx( ns );
 
-            Collection* coll = ctx.db()->getCollection( ns );
+            Collection* coll = ctx.db()->getCollection( txn, ns );
             if ( !coll ) {
                 errmsg = "ns does not exist";
                 return false;
@@ -1247,7 +1251,7 @@ namespace mongo {
             Client::ReadContext ctx(txn, ns);
             Database* d = ctx.ctx().db();
 
-            d->getStats( &result, scale );
+            d->getStats( txn, &result, scale );
 
             return true;
         }
diff --git a/src/mongo/db/dbhelpers.cpp b/src/mongo/db/dbhelpers.cpp
index 1a2e0c4652f..f36ea3c745a 100644
--- a/src/mongo/db/dbhelpers.cpp
+++ b/src/mongo/db/dbhelpers.cpp
@@ -81,11 +81,12 @@ namespace mongo {
     /* fetch a single object from collection ns that matches query
        set your db SavedContext first
     */
-    bool Helpers::findOne(Collection* collection, 
+    bool Helpers::findOne(OperationContext* txn,
+                          Collection* collection, 
                           const BSONObj &query, 
                           BSONObj& result, 
                           bool requireIndex) {
-        DiskLoc loc = findOne( collection, query, requireIndex );
+        DiskLoc loc = findOne( txn, collection, query, requireIndex );
         if ( loc.isNull() )
             return false;
         result = collection->docFor(loc);
@@ -95,7 +96,10 @@ namespace mongo {
     /* fetch a single object from collection ns that matches query
        set your db SavedContext first
     */
-    DiskLoc Helpers::findOne(Collection* collection, const BSONObj &query, bool requireIndex) {
+    DiskLoc Helpers::findOne(OperationContext* txn,
+                             Collection* collection,
+                             const BSONObj &query,
+                             bool requireIndex) {
         if ( !collection )
             return DiskLoc();
 
@@ -119,12 +123,17 @@ namespace mongo {
         return DiskLoc();
     }
 
-    bool Helpers::findById(Database* database, const char *ns, BSONObj query, BSONObj& result ,
-                           bool* nsFound , bool* indexFound ) {
+    bool Helpers::findById(OperationContext* txn,
+                           Database* database,
+                           const char *ns,
+                           BSONObj query,
+                           BSONObj& result,
+                           bool* nsFound,
+                           bool* indexFound) {
         Lock::assertAtLeastReadLocked(ns);
         invariant( database );
 
-        Collection* collection = database->getCollection( ns );
+        Collection* collection = database->getCollection( txn, ns );
         if ( !collection ) {
             return false;
         }
@@ -152,7 +161,9 @@ namespace mongo {
         return true;
     }
 
-    DiskLoc Helpers::findById(Collection* collection, const BSONObj& idquery) {
+    DiskLoc Helpers::findById(OperationContext* txn,
+                              Collection* collection,
+                              const BSONObj& idquery) {
         verify(collection);
         IndexCatalog* catalog = collection->getIndexCatalog();
         const IndexDescriptor* desc = catalog->findIdIndex();
@@ -163,57 +174,24 @@ namespace mongo {
         return accessMethod->findSingle( idquery["_id"].wrap() );
     }
 
-    vector<BSONObj> Helpers::findAll( const string& ns , const BSONObj& query ) {
-        Lock::assertAtLeastReadLocked(ns);
-        Client::Context ctx(ns);
-
-        CanonicalQuery* cq;
-        const NamespaceString nss(ns);
-        const WhereCallbackReal whereCallback(nss.db());
-
-        uassert(17236, "Could not canonicalize " + query.toString(),
-            CanonicalQuery::canonicalize(ns, query, &cq, whereCallback).isOK());
-
-        Runner* rawRunner;
-        uassert(17237, "Could not get runner for query " + query.toString(),
-                getRunner(ctx.db()->getCollection( ns ), cq, &rawRunner).isOK());
-
-        vector<BSONObj> all;
-
-        auto_ptr<Runner> runner(rawRunner);
-        Runner::RunnerState state;
-        BSONObj obj;
-        while (Runner::RUNNER_ADVANCED == (state = runner->getNext(&obj, NULL))) {
-            all.push_back(obj);
-        }
-
-        return all;
-    }
-
-    bool Helpers::isEmpty(const char *ns) {
-        Client::Context context(ns, storageGlobalParams.dbpath);
-        auto_ptr<Runner> runner(InternalPlanner::collectionScan(ns,
-                                                                context.db()->getCollection(ns)));
-        return Runner::RUNNER_EOF == runner->getNext(NULL, NULL);
-    }
-
     /* Get the first object from a collection.  Generally only useful if the collection
        only ever has a single object -- which is a "singleton collection.
 
        Returns: true if object exists.
     */
-    bool Helpers::getSingleton(const char *ns, BSONObj& result) {
+    bool Helpers::getSingleton(OperationContext* txn, const char *ns, BSONObj& result) {
         Client::Context context(ns);
         auto_ptr<Runner> runner(InternalPlanner::collectionScan(ns,
-                                                                context.db()->getCollection(ns)));
+                                                                context.db()->getCollection(txn,
+                                                                                            ns)));
         Runner::RunnerState state = runner->getNext(&result, NULL);
         context.getClient()->curop()->done();
         return Runner::RUNNER_ADVANCED == state;
     }
 
-    bool Helpers::getLast(const char *ns, BSONObj& result) {
+    bool Helpers::getLast(OperationContext* txn, const char *ns, BSONObj& result) {
         Client::Context ctx(ns);
-        Collection* coll = ctx.db()->getCollection( ns );
+        Collection* coll = ctx.db()->getCollection( txn, ns );
         auto_ptr<Runner> runner(InternalPlanner::collectionScan(ns,
                                                                 coll,
                                                                 InternalPlanner::BACKWARD));
@@ -303,7 +281,7 @@ namespace mongo {
                                          BSONObj* indexPattern ) {
 
         Client::ReadContext context(txn, ns);
-        Collection* collection = context.ctx().db()->getCollection( ns );
+        Collection* collection = context.ctx().db()->getCollection( txn, ns );
         if ( !collection )
             return false;
 
@@ -492,7 +470,7 @@ namespace mongo {
         *numDocs = 0;
 
         Client::ReadContext ctx(txn, ns);
-        Collection* collection = ctx.ctx().db()->getCollection( ns );
+        Collection* collection = ctx.ctx().db()->getCollection( txn, ns );
         if ( !collection ) return Status( ErrorCodes::NamespaceNotFound, ns );
 
         // Require single key
diff --git a/src/mongo/db/dbhelpers.h b/src/mongo/db/dbhelpers.h
index 2cba18345d5..be0ca859248 100644
--- a/src/mongo/db/dbhelpers.h
+++ b/src/mongo/db/dbhelpers.h
@@ -79,29 +79,30 @@ namespace mongo {
 
            @return true if object found
         */
-        static bool findOne(Collection* collection,
+        static bool findOne(OperationContext* txn,
+                            Collection* collection,
                             const BSONObj &query,
                             BSONObj& result, 
                             bool requireIndex = false);
 
-        static DiskLoc findOne(Collection* collection, const BSONObj &query, bool requireIndex);
-
-        /**
-         * have to be locked already
-         */
-        static std::vector<BSONObj> findAll( const std::string& ns , const BSONObj& query );
+        static DiskLoc findOne(OperationContext* txn,
+                               Collection* collection,
+                               const BSONObj &query,
+                               bool requireIndex);
 
         /**
          * @param foundIndex if passed in will be set to 1 if ns and index found
          * @return true if object found
          */
-        static bool findById(Database* db, const char *ns, BSONObj query, BSONObj& result,
+        static bool findById(OperationContext* txn,
+                             Database* db, const char *ns, BSONObj query, BSONObj& result,
                              bool* nsFound = 0, bool* indexFound = 0 );
 
         /* TODO: should this move into Collection?
          * uasserts if no _id index.
          * @return null loc if not found */
-        static DiskLoc findById(Collection* collection, const BSONObj& query);
+        static DiskLoc findById(OperationContext* txn,
+                                Collection* collection, const BSONObj& query);
 
         /** Get/put the first (or last) object from a collection.  Generally only useful if the collection
             only ever has a single object -- which is a "singleton collection".
@@ -110,11 +111,17 @@ namespace mongo {
 
             @return true if object exists.
         */
-        static bool getSingleton(const char *ns, BSONObj& result);
+        static bool getSingleton(OperationContext* txn, const char *ns, BSONObj& result);
         static void putSingleton(OperationContext* txn, const char *ns, BSONObj obj);
         static void putSingletonGod(OperationContext* txn, const char *ns, BSONObj obj, bool logTheOp);
-        static bool getFirst(const char *ns, BSONObj& result) { return getSingleton(ns, result); }
-        static bool getLast(const char *ns, BSONObj& result); // get last object int he collection; e.g. {$natural : -1}
+        static bool getFirst(OperationContext* txn, const char *ns, BSONObj& result) {
+            return getSingleton(txn, ns, result);
+        }
+
+        /**
+         * get last object int he collection; e.g. {$natural : -1}
+         */
+        static bool getLast(OperationContext* txn, const char *ns, BSONObj& result);
 
         /**
          * you have to lock
@@ -126,11 +133,6 @@ namespace mongo {
                             const BSONObj& o,
                             bool fromMigrate = false );
 
-        /** You do not need to set the database before calling.
-            @return true if collection is empty.
-        */
-        static bool isEmpty(const char *ns);
-
         // TODO: this should be somewhere else probably
         /* Takes object o, and returns a new object with the
          * same field elements but the names stripped out.
diff --git a/src/mongo/db/exec/stagedebug_cmd.cpp b/src/mongo/db/exec/stagedebug_cmd.cpp
index ca10066c960..c2f6698414d 100644
--- a/src/mongo/db/exec/stagedebug_cmd.cpp
+++ b/src/mongo/db/exec/stagedebug_cmd.cpp
@@ -120,7 +120,7 @@ namespace mongo {
 
             // Make sure the collection is valid.
             Database* db = ctx.ctx().db();
-            Collection* collection = db->getCollection(db->name() + '.' + collName);
+            Collection* collection = db->getCollection(txn, db->name() + '.' + collName);
             uassert(17446, "Couldn't find the collection " + collName, NULL != collection);
 
             // Pull out the plan
diff --git a/src/mongo/db/fts/fts_command_mongod.cpp b/src/mongo/db/fts/fts_command_mongod.cpp
index c422d9d8863..0a26ddc6240 100644
--- a/src/mongo/db/fts/fts_command_mongod.cpp
+++ b/src/mongo/db/fts/fts_command_mongod.cpp
@@ -112,7 +112,7 @@ namespace mongo {
             }
 
             Runner* rawRunner;
-            Status getRunnerStatus = getRunner(ctx.ctx().db()->getCollection(ns), cq, &rawRunner);
+            Status getRunnerStatus = getRunner(ctx.ctx().db()->getCollection(txn, ns), cq, &rawRunner);
             if (!getRunnerStatus.isOK()) {
                 errmsg = getRunnerStatus.reason();
                 return false;
diff --git a/src/mongo/db/geo/haystack.cpp b/src/mongo/db/geo/haystack.cpp
index 644c2ba60d2..db88a10a35c 100644
--- a/src/mongo/db/geo/haystack.cpp
+++ b/src/mongo/db/geo/haystack.cpp
@@ -79,7 +79,7 @@ namespace mongo {
                 return false;
             }
 
-            Collection* collection = db->getCollection( ns );
+            Collection* collection = db->getCollection( txn, ns );
             if ( !collection ) {
                 errmsg = "can't find ns";
                 return false;
diff --git a/src/mongo/db/index_builder.cpp b/src/mongo/db/index_builder.cpp
index 1e97c3da193..c3b3af8eb5a 100644
--- a/src/mongo/db/index_builder.cpp
+++ b/src/mongo/db/index_builder.cpp
@@ -79,9 +79,9 @@ namespace mongo {
     Status IndexBuilder::build(OperationContext* txn, Database* db) const {
         const string ns = _index["ns"].String();
 
-        Collection* c = db->getCollection( ns );
+        Collection* c = db->getCollection( txn, ns );
         if ( !c ) {
-            c = db->getOrCreateCollection( ns );
+            c = db->getOrCreateCollection( txn, ns );
             verify(c);
         }
 
diff --git a/src/mongo/db/index_rebuilder.cpp b/src/mongo/db/index_rebuilder.cpp
index b9c89ab8b04..e7a74014be3 100644
--- a/src/mongo/db/index_rebuilder.cpp
+++ b/src/mongo/db/index_rebuilder.cpp
@@ -96,7 +96,7 @@ namespace mongo {
             // for this namespace.
             Client::WriteContext ctx(&txn, ns);
 
-            Collection* collection = ctx.ctx().db()->getCollection( ns );
+            Collection* collection = ctx.ctx().db()->getCollection( &txn, ns );
             if ( collection == NULL )
                 continue;
 
diff --git a/src/mongo/db/instance.cpp b/src/mongo/db/instance.cpp
index 3e2566bde51..eabcc0ec0c4 100644
--- a/src/mongo/db/instance.cpp
+++ b/src/mongo/db/instance.cpp
@@ -793,7 +793,7 @@ namespace mongo {
             string targetNS = js["ns"].String();
             uassertStatusOK( userAllowedWriteNS( targetNS ) );
 
-            Collection* collection = ctx.db()->getCollection( targetNS );
+            Collection* collection = ctx.db()->getCollection( txn, targetNS );
             if ( !collection ) {
                 // implicitly create
                 collection = ctx.db()->createCollection( txn, targetNS );
@@ -822,7 +822,7 @@ namespace mongo {
         if ( !fixed.getValue().isEmpty() )
             js = fixed.getValue();
 
-        Collection* collection = ctx.db()->getCollection( ns );
+        Collection* collection = ctx.db()->getCollection( txn, ns );
         if ( !collection ) {
             collection = ctx.db()->createCollection( txn, ns );
             verify( collection );
@@ -937,7 +937,7 @@ namespace mongo {
             {
                 Lock::DBRead lk(txn->lockState(), repl::rsoplog);
                 BSONObj o;
-                if( Helpers::getFirst(repl::rsoplog, o) )
+                if( Helpers::getFirst(txn, repl::rsoplog, o) )
                     return true;
             }
         }
@@ -1018,11 +1018,10 @@ namespace {
             skip = 0;
         }
 
-        OperationContextImpl txn;
-        Lock::DBRead lk(txn.lockState(), ns);
+        Lock::DBRead lk(_txn->lockState(), ns);
         string errmsg;
         int errCode;
-        long long res = runCount( ns, _countCmd( ns , query , options , limit , skip ) , errmsg, errCode );
+        long long res = runCount( _txn, ns, _countCmd( ns , query , options , limit , skip ) , errmsg, errCode );
         if ( res == -1 ) {
             // namespace doesn't exist
             return 0;
diff --git a/src/mongo/db/ops/count.cpp b/src/mongo/db/ops/count.cpp
index 5ae6f8ed9c0..a602a1c4478 100644
--- a/src/mongo/db/ops/count.cpp
+++ b/src/mongo/db/ops/count.cpp
@@ -66,10 +66,14 @@ namespace mongo {
         return num;
     }
 
-    long long runCount( const string& ns, const BSONObj &cmd, string &err, int &errCode ) {
+    long long runCount(OperationContext* txn,
+                       const string& ns,
+                       const BSONObj &cmd,
+                       string &err,
+                       int &errCode) {
         // Lock 'ns'.
         Client::Context cx(ns);
-        Collection* collection = cx.db()->getCollection(ns);
+        Collection* collection = cx.db()->getCollection(txn, ns);
 
         if (NULL == collection) {
             err = "ns missing";
diff --git a/src/mongo/db/ops/count.h b/src/mongo/db/ops/count.h
index 94384529d6c..8040efb6028 100644
--- a/src/mongo/db/ops/count.h
+++ b/src/mongo/db/ops/count.h
@@ -32,6 +32,8 @@
 
 namespace mongo {
 
+    class OperationContext;
+
     /**
      * 'ns' is the namespace we're counting on.
      *
@@ -40,6 +42,10 @@ namespace mongo {
      * @return -1 on ns does not exist error and other errors, 0 on other errors, otherwise the
      * match count.
      */
-    long long runCount(const std::string& ns, const BSONObj& cmd, std::string& err, int& errCode );
+    long long runCount(OperationContext* txn,
+                       const std::string& ns,
+                       const BSONObj& cmd,
+                       std::string& err,
+                       int& errCode);
 
 } // namespace mongo
diff --git a/src/mongo/db/ops/delete_executor.cpp b/src/mongo/db/ops/delete_executor.cpp
index 1a0d3aa19aa..d891fb97e26 100644
--- a/src/mongo/db/ops/delete_executor.cpp
+++ b/src/mongo/db/ops/delete_executor.cpp
@@ -99,7 +99,7 @@ namespace mongo {
             }
         }
 
-        Collection* collection = db->getCollection(ns.ns());
+        Collection* collection = db->getCollection(txn, ns.ns());
         if (NULL == collection) {
             return 0;
         }
diff --git a/src/mongo/db/ops/update.cpp b/src/mongo/db/ops/update.cpp
index 9a1fd4e7f35..b47c8235fad 100644
--- a/src/mongo/db/ops/update.cpp
+++ b/src/mongo/db/ops/update.cpp
@@ -439,7 +439,7 @@ namespace mongo {
         const NamespaceString& nsString = request.getNamespaceString();
         UpdateLifecycle* lifecycle = request.getLifecycle();
 
-        Collection* collection = db->getCollection(nsString.ns());
+        Collection* collection = db->getCollection(txn, nsString.ns());
 
         validateUpdate(nsString.ns().c_str(), request.getUpdates(), request.getQuery());
 
@@ -765,7 +765,7 @@ namespace mongo {
 
         // Only create the collection if the doc will be inserted.
         if (!collection) {
-            collection = db->getCollection(request.getNamespaceString().ns());
+            collection = db->getCollection(txn, request.getNamespaceString().ns());
             if (!collection) {
                 collection = db->createCollection(txn, request.getNamespaceString().ns());
             }
diff --git a/src/mongo/db/pdfile.cpp b/src/mongo/db/pdfile.cpp
index 8624ab2ee42..182493e802a 100644
--- a/src/mongo/db/pdfile.cpp
+++ b/src/mongo/db/pdfile.cpp
@@ -111,7 +111,7 @@ namespace mongo {
             return Status( ErrorCodes::InvalidNamespace,
                            str::stream() << "invalid ns: " << ns );
 
-        Collection* collection = db->getCollection( ns );
+        Collection* collection = db->getCollection( txn, ns );
 
         if ( collection )
             return Status( ErrorCodes::NamespaceExists,
diff --git a/src/mongo/db/pipeline/pipeline_d.cpp b/src/mongo/db/pipeline/pipeline_d.cpp
index 4409b899c4c..b790fe4b4d3 100644
--- a/src/mongo/db/pipeline/pipeline_d.cpp
+++ b/src/mongo/db/pipeline/pipeline_d.cpp
@@ -65,7 +65,7 @@ namespace {
 
         bool isCapped(const NamespaceString& ns) {
             Client::ReadContext ctx(_ctx->opCtx, ns.ns());
-            Collection* collection = ctx.ctx().db()->getCollection(ns);
+            Collection* collection = ctx.ctx().db()->getCollection(_ctx->opCtx, ns);
             return collection && collection->isCapped();
         }
 
diff --git a/src/mongo/db/prefetch.cpp b/src/mongo/db/prefetch.cpp
index 36ad06ef964..7e463a592f6 100644
--- a/src/mongo/db/prefetch.cpp
+++ b/src/mongo/db/prefetch.cpp
@@ -79,7 +79,7 @@ namespace mongo {
         BSONObj obj = op.getObjectField(opField);
         const char *ns = op.getStringField("ns");
 
-        Collection* collection = db->getCollection( ns );
+        Collection* collection = db->getCollection( txn, ns );
         if ( !collection )
             return;
 
@@ -187,7 +187,7 @@ namespace mongo {
                 // we can probably use Client::Context here instead of ReadContext as we
                 // have locked higher up the call stack already
                 Client::ReadContext ctx(txn, ns);
-                if( Helpers::findById(ctx.ctx().db(), ns, builder.done(), result) ) {
+                if( Helpers::findById(txn, ctx.ctx().db(), ns, builder.done(), result) ) {
                     // do we want to use Record::touch() here?  it's pretty similar.
                     volatile char _dummy_char = '\0';
                     // Touch the first word on every page in order to fault it into memory
diff --git a/src/mongo/db/query/new_find.cpp b/src/mongo/db/query/new_find.cpp
index 7ed222b9f06..7834d7902e5 100644
--- a/src/mongo/db/query/new_find.cpp
+++ b/src/mongo/db/query/new_find.cpp
@@ -153,7 +153,7 @@ namespace mongo {
 
         // This is a read lock.
         scoped_ptr<Client::ReadContext> ctx(new Client::ReadContext(txn, ns));
-        Collection* collection = ctx->ctx().db()->getCollection(ns);
+        Collection* collection = ctx->ctx().db()->getCollection(txn, ns);
         uassert( 17356, "collection dropped between getMore calls", collection );
 
         QLOG() << "Running getMore, cursorid: " << cursorid << endl;
@@ -460,7 +460,7 @@ namespace mongo {
         // where-specific parsing code assumes we have a lock and creates execution machinery that
         // requires it.
         Client::ReadContext ctx(txn, q.ns);
-        Collection* collection = ctx.ctx().db()->getCollection( ns );
+        Collection* collection = ctx.ctx().db()->getCollection( txn, ns );
 
         // Parse the qm into a CanonicalQuery.
         CanonicalQuery* cq;
@@ -675,7 +675,7 @@ namespace mongo {
             // If we're tailing a capped collection, we don't bother saving the cursor if the
             // collection is empty. Otherwise, the semantics of the tailable cursor is that the
             // client will keep trying to read from it. So we'll keep it around.
-            Collection* collection = ctx.ctx().db()->getCollection(cq->ns());
+            Collection* collection = ctx.ctx().db()->getCollection(txn, cq->ns());
             if (collection && collection->numRecords() != 0 && pq.getNumToReturn() != 1) {
                 saveClientCursor = true;
             }
diff --git a/src/mongo/db/range_deleter_db_env.cpp b/src/mongo/db/range_deleter_db_env.cpp
index 39e0c81a465..0088b66ffe3 100644
--- a/src/mongo/db/range_deleter_db_env.cpp
+++ b/src/mongo/db/range_deleter_db_env.cpp
@@ -160,7 +160,7 @@ namespace mongo {
                                          const StringData& ns,
                                          std::set<CursorId>* openCursors) {
         Client::ReadContext ctx(txn, ns.toString());
-        Collection* collection = ctx.ctx().db()->getCollection( ns );
+        Collection* collection = ctx.ctx().db()->getCollection( txn, ns );
         if ( !collection )
             return;
 
diff --git a/src/mongo/db/repair_database.cpp b/src/mongo/db/repair_database.cpp
index 52ecec48a95..aac1c1b3eca 100644
--- a/src/mongo/db/repair_database.cpp
+++ b/src/mongo/db/repair_database.cpp
@@ -326,7 +326,7 @@ namespace mongo {
             {
                 string ns = dbName + ".system.namespaces";
                 Client::Context ctx( ns );
-                Collection* coll = originalDatabase->getCollection( ns );
+                Collection* coll = originalDatabase->getCollection( txn, ns );
                 if ( coll ) {
                     scoped_ptr<RecordIterator> it( coll->getIterator( DiskLoc(),
                                                                           false,
diff --git a/src/mongo/db/repl/health.cpp b/src/mongo/db/repl/health.cpp
index aed8a4baa9b..cfb1bd780de 100644
--- a/src/mongo/db/repl/health.cpp
+++ b/src/mongo/db/repl/health.cpp
@@ -217,7 +217,7 @@ namespace repl {
         }
     }
 
-    void ReplSetImpl::_summarizeAsHtml(stringstream& s) const {
+    void ReplSetImpl::_summarizeAsHtml(OperationContext* txn, stringstream& s) const {
         s << table(0, false);
         s << tr("Set name:", _name);
         s << tr("Majority up:", elect.aMajoritySeemsToBeUp()?"yes":"no" );
@@ -252,7 +252,7 @@ namespace repl {
             readlocktry lk(/*"local.replset.minvalid", */300);
             if( lk.got() ) {
                 BSONObj mv;
-                if( Helpers::getSingleton("local.replset.minvalid", mv) ) {
+                if( Helpers::getSingleton(txn, "local.replset.minvalid", mv) ) {
                     myMinValid = "minvalid:" + mv["ts"]._opTime().toString();
                 }
             }
diff --git a/src/mongo/db/repl/master_slave.cpp b/src/mongo/db/repl/master_slave.cpp
index ff2ff4921f5..93681b32d28 100644
--- a/src/mongo/db/repl/master_slave.cpp
+++ b/src/mongo/db/repl/master_slave.cpp
@@ -165,7 +165,7 @@ namespace repl {
             OperationContextImpl txn;
             Client::WriteContext ctx(&txn, "local");
             // local.me is an identifier for a server for getLastError w:2+
-            if (!Helpers::getSingleton("local.me", _me) ||
+            if (!Helpers::getSingleton(&txn, "local.me", _me) ||
                 !_me.hasField("host") ||
                 _me["host"].String() != myname) {
 
@@ -231,7 +231,7 @@ namespace repl {
     /* we reuse our existing objects so that we can keep our existing connection
        and cursor in effect.
     */
-    void ReplSource::loadAll(SourceVector &v) {
+    void ReplSource::loadAll(OperationContext* txn, SourceVector &v) {
         const char* localSources = "local.sources";
         Client::Context ctx(localSources);
         SourceVector old = v;
@@ -242,8 +242,9 @@ namespace repl {
             // check that no items are in sources other than that
             // add if missing
             int n = 0;
-            auto_ptr<Runner> runner(InternalPlanner::collectionScan(localSources,
-                                                                    ctx.db()->getCollection(localSources)));
+            auto_ptr<Runner> runner(
+                InternalPlanner::collectionScan(localSources,
+                                                ctx.db()->getCollection(txn, localSources)));
             BSONObj obj;
             Runner::RunnerState state;
             while (Runner::RUNNER_ADVANCED == (state = runner->getNext(&obj, NULL))) {
@@ -285,8 +286,9 @@ namespace repl {
             }
         }
 
-        auto_ptr<Runner> runner(InternalPlanner::collectionScan(localSources,
-                                                                ctx.db()->getCollection(localSources)));
+        auto_ptr<Runner> runner(
+            InternalPlanner::collectionScan(localSources,
+                                            ctx.db()->getCollection(txn, localSources)));
         BSONObj obj;
         Runner::RunnerState state;
         while (Runner::RUNNER_ADVANCED == (state = runner->getNext(&obj, NULL))) {
@@ -318,7 +320,7 @@ namespace repl {
         if ( !replAllDead )
             return;
         SourceVector sources;
-        ReplSource::loadAll(sources);
+        ReplSource::loadAll(txn, sources);
         for( SourceVector::iterator i = sources.begin(); i != sources.end(); ++i ) {
             log() << requester << " forcing resync from "  << (*i)->hostName << endl;
             (*i)->forceResync( txn, requester );
@@ -1020,10 +1022,11 @@ namespace repl {
                 1 = special sentinel indicating adaptive sleep recommended
     */
     int _replMain(ReplSource::SourceVector& sources, int& nApplied) {
+        OperationContextImpl txn;
         {
             ReplInfo r("replMain load sources");
             Lock::GlobalWrite lk;
-            ReplSource::loadAll(sources);
+            ReplSource::loadAll(&txn, sources);
             replSettings.fastsync = false; // only need this param for initial reset
         }
 
@@ -1245,6 +1248,7 @@ namespace repl {
             c = &cc();
         }
 
+        OperationContextImpl txn; // XXX
         Lock::GlobalRead lk;
         for( unsigned i = a; i <= b; i++ ) {
             const BSONObj& op = v[i];
@@ -1267,7 +1271,7 @@ namespace repl {
                     b.append(_id);
                     BSONObj result;
                     Client::Context ctx( ns );
-                    if( Helpers::findById(ctx.db(), ns, b.done(), result) )
+                    if( Helpers::findById(&txn, ctx.db(), ns, b.done(), result) )
                         _dummy_z += result.objsize(); // touch
                 }
             }
@@ -1301,7 +1305,7 @@ namespace repl {
                 b.append(_id);
                 BSONObj result;
                 Client::ReadContext ctx(txn, ns );
-                if( Helpers::findById(ctx.ctx().db(), ns, b.done(), result) )
+                if( Helpers::findById(txn, ctx.ctx().db(), ns, b.done(), result) )
                     _dummy_z += result.objsize(); // touch
             }
         }
diff --git a/src/mongo/db/repl/master_slave.h b/src/mongo/db/repl/master_slave.h
index ca21d180111..15445f68ede 100644
--- a/src/mongo/db/repl/master_slave.h
+++ b/src/mongo/db/repl/master_slave.h
@@ -138,7 +138,7 @@ namespace repl {
         int nClonedThisPass;
 
         typedef std::vector< shared_ptr< ReplSource > > SourceVector;
-        static void loadAll(SourceVector&);
+        static void loadAll(OperationContext* txn, SourceVector&);
         explicit ReplSource(BSONObj);
 
         /* -1 = error */
diff --git a/src/mongo/db/repl/oplog.cpp b/src/mongo/db/repl/oplog.cpp
index 474416dd250..1c40bbdfa6f 100644
--- a/src/mongo/db/repl/oplog.cpp
+++ b/src/mongo/db/repl/oplog.cpp
@@ -422,7 +422,7 @@ namespace repl {
             _logOp(txn, opstr, ns, 0, obj, patt, b, fromMigrate);
         }
 
-        logOpForSharding(opstr, ns, obj, patt, fromMigrate);
+        logOpForSharding(txn, opstr, ns, obj, patt, fromMigrate);
         logOpForDbHash(ns);
         getGlobalAuthorizationManager()->logOp(opstr, ns, obj, patt, b);
 
@@ -672,9 +672,9 @@ namespace repl {
                     // thus this is not ideal.
                     else {
                         if (collection == NULL ||
-                            (indexCatalog->haveIdIndex() && Helpers::findById(collection, updateCriteria).isNull()) ||
+                            (indexCatalog->haveIdIndex() && Helpers::findById(txn, collection, updateCriteria).isNull()) ||
                             // capped collections won't have an _id index
-                            (!indexCatalog->haveIdIndex() && Helpers::findOne(collection, updateCriteria, false).isNull())) {
+                            (!indexCatalog->haveIdIndex() && Helpers::findOne(txn, collection, updateCriteria, false).isNull())) {
                             failedUpdate = true;
                             log() << "replication couldn't find doc: " << op.toString() << endl;
                         }
diff --git a/src/mongo/db/repl/repl_set.h b/src/mongo/db/repl/repl_set.h
index 914f13751cf..981e2ee708a 100644
--- a/src/mongo/db/repl/repl_set.h
+++ b/src/mongo/db/repl/repl_set.h
@@ -63,7 +63,7 @@ namespace repl {
         string name() const { return ReplSetImpl::name(); }
         virtual const ReplSetConfig& config() { return ReplSetImpl::config(); }
         void getOplogDiagsAsHtml(unsigned server_id, stringstream& ss) const { _getOplogDiagsAsHtml(server_id,ss); }
-        void summarizeAsHtml(stringstream& ss) const { _summarizeAsHtml(ss); }
+        void summarizeAsHtml(OperationContext* txn, stringstream& ss) const { _summarizeAsHtml(txn, ss); }
         void summarizeStatus(BSONObjBuilder& b) const  { _summarizeStatus(b); }
         void fillIsMaster(BSONObjBuilder& b) { _fillIsMaster(b); }
         threadpool::ThreadPool& getPrefetchPool() { return ReplSetImpl::getPrefetchPool(); }
diff --git a/src/mongo/db/repl/repl_set_impl.cpp b/src/mongo/db/repl/repl_set_impl.cpp
index 5274e461f07..5d7a37d8806 100644
--- a/src/mongo/db/repl/repl_set_impl.cpp
+++ b/src/mongo/db/repl/repl_set_impl.cpp
@@ -438,7 +438,7 @@ namespace {
         OperationContextImpl txn; // XXX?
         Lock::DBRead lk(txn.lockState(), rsoplog);
         BSONObj o;
-        if (Helpers::getLast(rsoplog, o)) {
+        if (Helpers::getLast(&txn, rsoplog, o)) {
             lastH = o["h"].numberLong();
             lastOpTimeWritten = o["ts"]._opTime();
             uassert(13290, "bad replSet oplog entry?", quiet || !lastOpTimeWritten.isNull());
@@ -449,7 +449,8 @@ namespace {
         OperationContextImpl txn; // XXX?
         Lock::DBRead lk(txn.lockState(), rsoplog);
         BSONObj o;
-        uassert(17347, "Problem reading earliest entry from oplog", Helpers::getFirst(rsoplog, o));
+        uassert(17347, "Problem reading earliest entry from oplog",
+                Helpers::getFirst(&txn, rsoplog, o));
         return o["ts"]._opTime();
     }
 
@@ -876,7 +877,7 @@ namespace {
         OperationContextImpl txn; // XXX?
         Lock::DBRead lk (txn.lockState(), "local");
         BSONObj mv;
-        if (Helpers::getSingleton("local.replset.minvalid", mv)) {
+        if (Helpers::getSingleton(&txn, "local.replset.minvalid", mv)) {
             return mv[_initialSyncFlagString].trueValue();
         }
         return false;
@@ -897,7 +898,7 @@ namespace {
         OperationContextImpl txn; // XXX?
         Lock::DBRead lk(txn.lockState(), "local.replset.minvalid");
         BSONObj mv;
-        if (Helpers::getSingleton("local.replset.minvalid", mv)) {
+        if (Helpers::getSingleton(&txn, "local.replset.minvalid", mv)) {
             return mv["ts"]._opTime();
         }
         return OpTime();
diff --git a/src/mongo/db/repl/repl_set_impl.h b/src/mongo/db/repl/repl_set_impl.h
index 1fc7529dd2d..b5b6254826d 100644
--- a/src/mongo/db/repl/repl_set_impl.h
+++ b/src/mongo/db/repl/repl_set_impl.h
@@ -198,7 +198,7 @@ namespace repl {
         MemberState state() const { return box.getState(); }
         void _fatal();
         void _getOplogDiagsAsHtml(unsigned server_id, stringstream& ss) const;
-        void _summarizeAsHtml(stringstream&) const;
+        void _summarizeAsHtml(OperationContext* txn, stringstream&) const;
         void _summarizeStatus(BSONObjBuilder&) const; // for replSetGetStatus command
 
         /* call afer constructing to start - returns fairly quickly after launching its threads */
diff --git a/src/mongo/db/repl/repl_settings.cpp b/src/mongo/db/repl/repl_settings.cpp
index 48dad4218cc..65db46755ab 100644
--- a/src/mongo/db/repl/repl_settings.cpp
+++ b/src/mongo/db/repl/repl_settings.cpp
@@ -90,8 +90,10 @@ namespace repl {
             {
                 const char* localSources = "local.sources";
                 Client::ReadContext ctx(txn, localSources);
-                auto_ptr<Runner> runner(InternalPlanner::collectionScan(localSources,
-                                                                        ctx.ctx().db()->getCollection(localSources)));
+                auto_ptr<Runner> runner(
+                    InternalPlanner::collectionScan(localSources,
+                                                    ctx.ctx().db()->getCollection(txn,
+                                                                                  localSources)));
                 BSONObj obj;
                 Runner::RunnerState state;
                 while (Runner::RUNNER_ADVANCED == (state = runner->getNext(&obj, NULL))) {
diff --git a/src/mongo/db/repl/replset_web_handler.cpp b/src/mongo/db/repl/replset_web_handler.cpp
index f9d271a1e09..8c71fa2748b 100644
--- a/src/mongo/db/repl/replset_web_handler.cpp
+++ b/src/mongo/db/repl/replset_web_handler.cpp
@@ -59,7 +59,7 @@ namespace repl {
                 responseMsg = _replSetOplog(params);
             }
             else
-                responseMsg = _replSet();
+                responseMsg = _replSet(txn);
             responseCode = 200;
         }
 
@@ -93,7 +93,7 @@ namespace repl {
         }
 
         /* /_replSet show replica set status in html format */
-        string _replSet() {
+        string _replSet(OperationContext* txn) {
             stringstream s;
             s << start("Replica Set Status " + prettyHostName());
             s << p( a("/", "back", "Home") + " | " +
@@ -112,7 +112,7 @@ namespace repl {
             }
             else {
                 try {
-                    theReplSet->summarizeAsHtml(s);
+                    theReplSet->summarizeAsHtml(txn, s);
                 }
                 catch(...) { s << "error summarizing replset status\n"; }
             }
diff --git a/src/mongo/db/repl/rs_initialsync.cpp b/src/mongo/db/repl/rs_initialsync.cpp
index 32d9d7e6e3c..be6c8aaf75a 100644
--- a/src/mongo/db/repl/rs_initialsync.cpp
+++ b/src/mongo/db/repl/rs_initialsync.cpp
@@ -133,7 +133,7 @@ namespace repl {
         OperationContextImpl txn;
         Client::WriteContext ctx(&txn, rsoplog);
 
-        Collection* collection = ctx.ctx().db()->getCollection(rsoplog);
+        Collection* collection = ctx.ctx().db()->getCollection(&txn, rsoplog);
 
         // temp
         if( collection->numRecords() == 0 )
diff --git a/src/mongo/db/repl/rs_initiate.cpp b/src/mongo/db/repl/rs_initiate.cpp
index 23ec6697a57..e50d2a80568 100644
--- a/src/mongo/db/repl/rs_initiate.cpp
+++ b/src/mongo/db/repl/rs_initiate.cpp
@@ -207,7 +207,7 @@ namespace repl {
                    it is ok if the initiating member has *other* data than that.
                    */
                 BSONObj o;
-                if( Helpers::getFirst(rsoplog, o) ) {
+                if( Helpers::getFirst(txn, rsoplog, o) ) {
                     errmsg = rsoplog + string(" is not empty on the initiating member.  cannot initiate.");
                     return false;
                 }
diff --git a/src/mongo/db/repl/rs_rollback.cpp b/src/mongo/db/repl/rs_rollback.cpp
index b8bc672753f..efdcee062a2 100644
--- a/src/mongo/db/repl/rs_rollback.cpp
+++ b/src/mongo/db/repl/rs_rollback.cpp
@@ -231,12 +231,13 @@ namespace repl {
     int getRBID(DBClientConnection*);
 
     static void syncRollbackFindCommonPoint(DBClientConnection* them, FixUpInfo& fixUpInfo) {
+        OperationContextImpl txn; // XXX
         verify(Lock::isLocked());
         Client::Context ctx(rsoplog);
 
         boost::scoped_ptr<Runner> runner(
                 InternalPlanner::collectionScan(rsoplog,
-                                                ctx.db()->getCollection(rsoplog),
+                                                ctx.db()->getCollection(&txn, rsoplog),
                                                 InternalPlanner::BACKWARD));
 
         BSONObj ourObj;
@@ -484,7 +485,7 @@ namespace repl {
 
         sethbmsg("rollback 4.7");
         Client::Context ctx(rsoplog);
-        Collection* oplogCollection = ctx.db()->getCollection(rsoplog);
+        Collection* oplogCollection = ctx.db()->getCollection(&txn, rsoplog);
         uassert(13423,
                 str::stream() << "replSet error in rollback can't find " << rsoplog,
                 oplogCollection);
@@ -516,7 +517,7 @@ namespace repl {
 
                 // Add the doc to our rollback file
                 BSONObj obj;
-                bool found = Helpers::findOne(ctx.db()->getCollection(doc.ns), pattern, obj, false);
+                bool found = Helpers::findOne(&txn, ctx.db()->getCollection(&txn, doc.ns), pattern, obj, false);
                 if (found) {
                     removeSaver->goingToDelete(obj);
                 }
@@ -529,7 +530,7 @@ namespace repl {
                     // TODO 1.6 : can't delete from a capped collection.  need to handle that here.
                     deletes++;
 
-                    Collection* collection = ctx.db()->getCollection(doc.ns);
+                    Collection* collection = ctx.db()->getCollection(&txn, doc.ns);
                     if (collection) {
                         if (collection->isCapped()) {
                             // can't delete from a capped collection - so we truncate instead. if
@@ -538,7 +539,7 @@ namespace repl {
                                 // TODO: IIRC cappedTruncateAfter does not handle completely empty.
                                 // this will crazy slow if no _id index.
                                 long long start = Listener::getElapsedTimeMillis();
-                                DiskLoc loc = Helpers::findOne(collection, pattern, false);
+                                DiskLoc loc = Helpers::findOne(&txn, collection, pattern, false);
                                 if (Listener::getElapsedTimeMillis() - start > 200)
                                     log() << "replSet warning roll back slow no _id index for "
                                           << doc.ns << " perhaps?" << rsLog;
@@ -657,7 +658,7 @@ namespace repl {
             OperationContextImpl txn;
             Lock::DBRead lk(txn.lockState(), "local.replset.minvalid");
             BSONObj mv;
-            if (Helpers::getSingleton("local.replset.minvalid", mv)) {
+            if (Helpers::getSingleton(&txn, "local.replset.minvalid", mv)) {
                 OpTime minvalid = mv["ts"]._opTime();
                 if (minvalid > lastOpTimeWritten) {
                     log() << "replSet need to rollback, but in inconsistent state";
diff --git a/src/mongo/db/repl/sync.cpp b/src/mongo/db/repl/sync.cpp
index 888edbeb99a..8ca15ed9386 100644
--- a/src/mongo/db/repl/sync.cpp
+++ b/src/mongo/db/repl/sync.cpp
@@ -48,12 +48,12 @@ namespace repl {
         hn = hostname;
     }
 
-    BSONObj Sync::getMissingDoc(Database* db, const BSONObj& o) {
+    BSONObj Sync::getMissingDoc(OperationContext* txn, Database* db, const BSONObj& o) {
         OplogReader missingObjReader; // why are we using OplogReader to run a non-oplog query?
         const char *ns = o.getStringField("ns");
 
         // capped collections
-        Collection* collection = db->getCollection(ns);
+        Collection* collection = db->getCollection(txn, ns);
         if ( collection && collection->isCapped() ) {
             log() << "replication missing doc, but this is okay for a capped collection (" << ns << ")" << endl;
             return BSONObj();
@@ -115,7 +115,7 @@ namespace repl {
         // we don't have the object yet, which is possible on initial sync.  get it.
         log() << "replication info adding missing object" << endl; // rare enough we can log
 
-        BSONObj missingObj = getMissingDoc(ctx.db(), o);
+        BSONObj missingObj = getMissingDoc(&txn, ctx.db(), o);
 
         if( missingObj.isEmpty() ) {
             log() << "replication missing object not found on source. presumably deleted later in oplog" << endl;
@@ -125,7 +125,7 @@ namespace repl {
             return false;
         }
         else {
-            Collection* collection = ctx.db()->getOrCreateCollection( ns );
+            Collection* collection = ctx.db()->getOrCreateCollection( &txn, ns );
             verify( collection ); // should never happen
             StatusWith<DiskLoc> result = collection->insertDocument( &txn, missingObj, true );
             uassert(15917,
diff --git a/src/mongo/db/repl/sync.h b/src/mongo/db/repl/sync.h
index e86997cad6c..67cb5e63a60 100644
--- a/src/mongo/db/repl/sync.h
+++ b/src/mongo/db/repl/sync.h
@@ -34,6 +34,7 @@
 
 namespace mongo {
     class Database;
+    class OperationContext;
 
 namespace repl {
 
@@ -43,7 +44,7 @@ namespace repl {
     public:
         Sync(const std::string& hostname) : hn(hostname) {}
         virtual ~Sync() {}
-        virtual BSONObj getMissingDoc(Database* db, const BSONObj& o);
+        virtual BSONObj getMissingDoc(OperationContext* txn, Database* db, const BSONObj& o);
 
         /**
          * If applyOperation_inlock should be called again after an update fails.
diff --git a/src/mongo/db/repl/sync_source_feedback.cpp b/src/mongo/db/repl/sync_source_feedback.cpp
index d30eb517898..774748288b5 100644
--- a/src/mongo/db/repl/sync_source_feedback.cpp
+++ b/src/mongo/db/repl/sync_source_feedback.cpp
@@ -70,7 +70,7 @@ namespace repl {
             Client::WriteContext ctx(&txn, "local");
 
             // local.me is an identifier for a server for getLastError w:2+
-            if (!Helpers::getSingleton("local.me", _me) ||
+            if (!Helpers::getSingleton(&txn, "local.me", _me) ||
                 !_me.hasField("host") ||
                 _me["host"].String() != myname) {
 
diff --git a/src/mongo/db/ttl.cpp b/src/mongo/db/ttl.cpp
index c497c8ed7e4..cb861e48ec5 100644
--- a/src/mongo/db/ttl.cpp
+++ b/src/mongo/db/ttl.cpp
@@ -117,7 +117,7 @@ namespace mongo {
 
                     OperationContextImpl txn;
                     Client::WriteContext ctx(&txn,  ns );
-                    Collection* collection = ctx.ctx().db()->getCollection( ns );
+                    Collection* collection = ctx.ctx().db()->getCollection( &txn, ns );
                     if ( !collection ) {
                         // collection was dropped
                         continue;
diff --git a/src/mongo/dbtests/clienttests.cpp b/src/mongo/dbtests/clienttests.cpp
index 194cc048046..2affdf56b85 100644
--- a/src/mongo/dbtests/clienttests.cpp
+++ b/src/mongo/dbtests/clienttests.cpp
@@ -128,7 +128,7 @@ namespace ClientTests {
             db.insert(ns(), BSON("x" << 1 << "y" << 2));
             db.insert(ns(), BSON("x" << 2 << "y" << 2));
 
-            Collection* collection = ctx.ctx().db()->getCollection( ns() );
+            Collection* collection = ctx.ctx().db()->getCollection( &txn, ns() );
             ASSERT( collection );
             IndexCatalog* indexCatalog = collection->getIndexCatalog();
 
diff --git a/src/mongo/dbtests/counttests.cpp b/src/mongo/dbtests/counttests.cpp
index 729443e2835..7ece0d6e0ee 100644
--- a/src/mongo/dbtests/counttests.cpp
+++ b/src/mongo/dbtests/counttests.cpp
@@ -41,18 +41,10 @@
 namespace CountTests {
 
     class Base {
-        OperationContextImpl _txn;
-        Lock::DBWrite lk;
-
-        Client::Context _context;
-
-        Database* _database;
-        Collection* _collection;
-
     public:
         Base() : lk(_txn.lockState(), ns()), _context( ns() ) {
             _database = _context.db();
-            _collection = _database->getCollection( ns() );
+            _collection = _database->getCollection( &_txn, ns() );
             if ( _collection ) {
                 _database->dropCollection( &_txn, ns() );
             }
@@ -100,6 +92,17 @@ namespace CountTests {
         static BSONObj countCommand( const BSONObj &query ) {
             return BSON( "query" << query );
         }
+
+        OperationContextImpl _txn;
+
+    private:
+        Lock::DBWrite lk;
+
+        Client::Context _context;
+
+        Database* _database;
+        Collection* _collection;
+
     };
     
     class Basic : public Base {
@@ -109,7 +112,7 @@ namespace CountTests {
             BSONObj cmd = fromjson( "{\"query\":{}}" );
             string err;
             int errCode;
-            ASSERT_EQUALS( 1, runCount( ns(), cmd, err, errCode ) );
+            ASSERT_EQUALS( 1, runCount( &_txn, ns(), cmd, err, errCode ) );
         }
     };
     
@@ -122,7 +125,7 @@ namespace CountTests {
             BSONObj cmd = fromjson( "{\"query\":{\"a\":\"b\"}}" );
             string err;
             int errCode;
-            ASSERT_EQUALS( 2, runCount( ns(), cmd, err, errCode ) );
+            ASSERT_EQUALS( 2, runCount( &_txn, ns(), cmd, err, errCode ) );
         }
     };
     
@@ -134,7 +137,7 @@ namespace CountTests {
             BSONObj cmd = fromjson( "{\"query\":{},\"fields\":{\"a\":1}}" );
             string err;
             int errCode;
-            ASSERT_EQUALS( 2, runCount( ns(), cmd, err, errCode ) );
+            ASSERT_EQUALS( 2, runCount( &_txn, ns(), cmd, err, errCode ) );
         }
     };
     
@@ -147,7 +150,7 @@ namespace CountTests {
             BSONObj cmd = fromjson( "{\"query\":{\"a\":\"b\"},\"fields\":{\"a\":1}}" );
             string err;
             int errCode;
-            ASSERT_EQUALS( 1, runCount( ns(), cmd, err, errCode ) );
+            ASSERT_EQUALS( 1, runCount( &_txn, ns(), cmd, err, errCode ) );
         }
     };
     
@@ -159,7 +162,7 @@ namespace CountTests {
             BSONObj cmd = fromjson( "{\"query\":{\"a\":/^b/}}" );
             string err;
             int errCode;
-            ASSERT_EQUALS( 1, runCount( ns(), cmd, err, errCode ) );
+            ASSERT_EQUALS( 1, runCount( &_txn, ns(), cmd, err, errCode ) );
         }
     };
 
diff --git a/src/mongo/dbtests/dbhelper_tests.cpp b/src/mongo/dbtests/dbhelper_tests.cpp
index 0cee60de170..3c74b2af526 100644
--- a/src/mongo/dbtests/dbhelper_tests.cpp
+++ b/src/mongo/dbtests/dbhelper_tests.cpp
@@ -151,7 +151,7 @@ namespace mongo {
             ASSERT_LESS_THAN( estSizeBytes, maxSizeBytes );
 
             Database* db = dbHolder().get(nsToDatabase(range.ns), storageGlobalParams.dbpath);
-            const Collection* collection = db->getCollection(ns);
+            const Collection* collection = db->getCollection(&txn, ns);
 
             // Make sure all the disklocs actually correspond to the right info
             for ( set<DiskLoc>::const_iterator it = locs.begin(); it != locs.end(); ++it ) {
diff --git a/src/mongo/dbtests/documentsourcetests.cpp b/src/mongo/dbtests/documentsourcetests.cpp
index 652958c2efe..a6425e1748c 100644
--- a/src/mongo/dbtests/documentsourcetests.cpp
+++ b/src/mongo/dbtests/documentsourcetests.cpp
@@ -170,7 +170,7 @@ namespace DocumentSourceTests {
                 CanonicalQuery* cq;
                 uassertStatusOK(CanonicalQuery::canonicalize(ns, /*query=*/BSONObj(), &cq));
                 Runner* runnerBare;
-                uassertStatusOK(getRunner(ctx.ctx().db()->getCollection(ns), cq, &runnerBare));
+                uassertStatusOK(getRunner(ctx.ctx().db()->getCollection(&_opCtx, ns), cq, &runnerBare));
 
                 _runner.reset(runnerBare);
                 _runner->saveState();
diff --git a/src/mongo/dbtests/indexupdatetests.cpp b/src/mongo/dbtests/indexupdatetests.cpp
index 792c1071d3e..755c996c5c0 100644
--- a/src/mongo/dbtests/indexupdatetests.cpp
+++ b/src/mongo/dbtests/indexupdatetests.cpp
@@ -63,7 +63,7 @@ namespace IndexUpdateTests {
             killCurrentOp.reset();
         }
         Collection* collection() {
-            return _ctx.ctx().db()->getCollection( _ns );
+            return _ctx.ctx().db()->getCollection( &_txn, _ns );
         }
     protected:
     // QUERY_MIGRATION
diff --git a/src/mongo/dbtests/oplogstarttests.cpp b/src/mongo/dbtests/oplogstarttests.cpp
index ab4acc8b90f..d04b7d19c6e 100644
--- a/src/mongo/dbtests/oplogstarttests.cpp
+++ b/src/mongo/dbtests/oplogstarttests.cpp
@@ -38,12 +38,11 @@ namespace OplogStartTests {
     class Base {
     public:
         Base() : _context(ns()) {
-            OperationContextImpl txn;
-            Collection* c = _context.db()->getCollection(&txn, ns());
+            Collection* c = _context.db()->getCollection(&_txn, ns());
             if (!c) {
-                c = _context.db()->createCollection(&txn, ns());
+                c = _context.db()->createCollection(&_txn, ns());
             }
-            c->getIndexCatalog()->ensureHaveIdIndex(&txn);
+            c->getIndexCatalog()->ensureHaveIdIndex(&_txn);
         }
 
         ~Base() {
@@ -62,7 +61,7 @@ namespace OplogStartTests {
         }
 
         Collection* collection() {
-            return _context.db()->getCollection( ns() );
+            return _context.db()->getCollection( &_txn, ns() );
         }
 
         DBDirectClient *client() const { return &_client; }
@@ -89,6 +88,7 @@ namespace OplogStartTests {
         scoped_ptr<OplogStart> _stage;
 
     private:
+        OperationContextImpl _txn;
         Lock::GlobalWrite lk;
         Client::Context _context;
 
diff --git a/src/mongo/dbtests/pdfiletests.cpp b/src/mongo/dbtests/pdfiletests.cpp
index 5ef98e0b08b..e62bce62067 100644
--- a/src/mongo/dbtests/pdfiletests.cpp
+++ b/src/mongo/dbtests/pdfiletests.cpp
@@ -60,7 +60,7 @@ namespace PdfileTests {
                 return "unittests.pdfiletests.Insert";
             }
             Collection* collection() {
-                return _context.db()->getCollection( ns() );
+                return _context.db()->getCollection( &_txn, ns() );
             }
 
             Lock::GlobalWrite lk_;
diff --git a/src/mongo/dbtests/plan_ranking.cpp b/src/mongo/dbtests/plan_ranking.cpp
index 02939707de3..fbf8a507b6c 100644
--- a/src/mongo/dbtests/plan_ranking.cpp
+++ b/src/mongo/dbtests/plan_ranking.cpp
@@ -88,7 +88,7 @@ namespace PlanRankingTests {
          */
         QuerySolution* pickBestPlan(CanonicalQuery* cq) {
             Client::ReadContext ctx(&_txn, ns);
-            Collection* collection = ctx.ctx().db()->getCollection(ns);
+            Collection* collection = ctx.ctx().db()->getCollection(&_txn, ns);
 
             QueryPlannerParams plannerParams;
             fillOutPlannerParams(collection, cq, &plannerParams);
diff --git a/src/mongo/dbtests/query_multi_plan_runner.cpp b/src/mongo/dbtests/query_multi_plan_runner.cpp
index 99d1f61d172..30393e396f4 100644
--- a/src/mongo/dbtests/query_multi_plan_runner.cpp
+++ b/src/mongo/dbtests/query_multi_plan_runner.cpp
@@ -67,8 +67,8 @@ namespace QueryMultiPlanRunner {
             _client.ensureIndex(ns(), obj);
         }
 
-        IndexDescriptor* getIndex(Database* db, const BSONObj& obj) {
-            const Collection* collection = db->getCollection( ns() );
+        IndexDescriptor* getIndex(OperationContext* txn, Database* db, const BSONObj& obj) {
+            const Collection* collection = db->getCollection( txn, ns() );
             return collection->getIndexCatalog()->findIndexByKeyPattern(obj);
         }
 
@@ -107,14 +107,14 @@ namespace QueryMultiPlanRunner {
             // Every call to work() returns something so this should clearly win (by current scoring
             // at least).
             IndexScanParams ixparams;
-            ixparams.descriptor = getIndex(ctx.ctx().db(), BSON("foo" << 1));
+            ixparams.descriptor = getIndex(&txn, ctx.ctx().db(), BSON("foo" << 1));
             ixparams.bounds.isSimpleRange = true;
             ixparams.bounds.startKey = BSON("" << 7);
             ixparams.bounds.endKey = BSON("" << 7);
             ixparams.bounds.endKeyInclusive = true;
             ixparams.direction = 1;
 
-            const Collection* coll = ctx.ctx().db()->getCollection(ns());
+            const Collection* coll = ctx.ctx().db()->getCollection(&txn, ns());
 
             auto_ptr<WorkingSet> sharedWs(new WorkingSet());
             IndexScan* ix = new IndexScan(ixparams, sharedWs.get(), NULL);
@@ -122,7 +122,7 @@ namespace QueryMultiPlanRunner {
 
             // Plan 1: CollScan with matcher.
             CollectionScanParams csparams;
-            csparams.collection = ctx.ctx().db()->getCollection( ns() );
+            csparams.collection = ctx.ctx().db()->getCollection( &txn, ns() );
             csparams.direction = CollectionScanParams::FORWARD;
 
             // Make the filter.
@@ -139,7 +139,7 @@ namespace QueryMultiPlanRunner {
             verify(CanonicalQuery::canonicalize(ns(), BSON("foo" << 7), &cq).isOK());
             verify(NULL != cq);
 
-            MultiPlanStage* mps = new MultiPlanStage(ctx.ctx().db()->getCollection(ns()),cq);
+            MultiPlanStage* mps = new MultiPlanStage(ctx.ctx().db()->getCollection(&txn, ns()),cq);
             mps->addPlan(createQuerySolution(), firstRoot.release(), sharedWs.get());
             mps->addPlan(createQuerySolution(), secondRoot.release(), sharedWs.get());
 
@@ -149,7 +149,7 @@ namespace QueryMultiPlanRunner {
             ASSERT_EQUALS(0, mps->bestPlanIdx());
 
             SingleSolutionRunner sr(
-                ctx.ctx().db()->getCollection(ns()),
+                ctx.ctx().db()->getCollection(&txn, ns()),
                 cq,
                 mps->bestSolution(),
                 mps,
diff --git a/src/mongo/dbtests/query_single_solution_runner.cpp b/src/mongo/dbtests/query_single_solution_runner.cpp
index 3e2e1330323..246cf66df1a 100644
--- a/src/mongo/dbtests/query_single_solution_runner.cpp
+++ b/src/mongo/dbtests/query_single_solution_runner.cpp
@@ -36,10 +36,9 @@
 #include "mongo/db/instance.h"
 #include "mongo/db/json.h"
 #include "mongo/db/matcher/expression_parser.h"
+#include "mongo/db/operation_context_impl.h"
 #include "mongo/db/query/query_solution.h"
 #include "mongo/db/query/single_solution_runner.h"
-#include "mongo/db/catalog/collection.h"
-#include "mongo/db/operation_context_impl.h"
 #include "mongo/dbtests/dbtests.h"
 
 namespace QuerySingleSolutionRunner {
@@ -82,7 +81,7 @@ namespace QuerySingleSolutionRunner {
         SingleSolutionRunner* makeCollScanRunner(Client::Context& ctx,
                                                  BSONObj& filterObj) {
             CollectionScanParams csparams;
-            csparams.collection = ctx.db()->getCollection( ns() );
+            csparams.collection = ctx.db()->getCollection( &_txn, ns() );
             csparams.direction = CollectionScanParams::FORWARD;
             auto_ptr<WorkingSet> ws(new WorkingSet());
             // Parse the filter.
@@ -97,7 +96,7 @@ namespace QuerySingleSolutionRunner {
             verify(NULL != cq);
 
             // Hand the plan off to the single solution runner.
-            SingleSolutionRunner* ssr = new SingleSolutionRunner(ctx.db()->getCollection(ns()),
+            SingleSolutionRunner* ssr = new SingleSolutionRunner(ctx.db()->getCollection(&_txn, ns()),
                                                                  cq,
                                                                  new QuerySolution(),
                                                                  root.release(),
@@ -129,7 +128,7 @@ namespace QuerySingleSolutionRunner {
             ixparams.bounds.endKeyInclusive = true;
             ixparams.direction = 1;
 
-            const Collection* coll = context.db()->getCollection(ns());
+            const Collection* coll = context.db()->getCollection(&_txn, ns());
 
             auto_ptr<WorkingSet> ws(new WorkingSet());
             IndexScan* ix = new IndexScan(ixparams, ws.get(), NULL);
@@ -149,7 +148,7 @@ namespace QuerySingleSolutionRunner {
 
         size_t numCursors() {
             Client::ReadContext ctx(&_txn, ns() );
-            Collection* collection = ctx.ctx().db()->getCollection( ns() );
+            Collection* collection = ctx.ctx().db()->getCollection( &_txn, ns() );
             if ( !collection )
                 return 0;
             return collection->cursorCache()->numCursors();
@@ -157,13 +156,13 @@ namespace QuerySingleSolutionRunner {
 
         void registerRunner( Runner* runner ) {
             Client::ReadContext ctx(&_txn, ns());
-            Collection* collection = ctx.ctx().db()->getOrCreateCollection( ns() );
+            Collection* collection = ctx.ctx().db()->getOrCreateCollection( &_txn, ns() );
             return collection->cursorCache()->registerRunner( runner );
         }
 
         void deregisterRunner( Runner* runner ) {
             Client::ReadContext ctx(&_txn, ns());
-            Collection* collection = ctx.ctx().db()->getOrCreateCollection( ns() );
+            Collection* collection = ctx.ctx().db()->getOrCreateCollection( &_txn, ns() );
             return collection->cursorCache()->deregisterRunner( runner );
         }
 
@@ -172,7 +171,7 @@ namespace QuerySingleSolutionRunner {
 
     private:
         IndexDescriptor* getIndex(Database* db, const BSONObj& obj) {
-            Collection* collection = db->getCollection( ns() );
+            Collection* collection = db->getCollection( &_txn, ns() );
             return collection->getIndexCatalog()->findIndexByKeyPattern(obj);
         }
 
@@ -348,13 +347,13 @@ namespace QuerySingleSolutionRunner {
                 SingleSolutionRunner* ssr = makeCollScanRunner(ctx.ctx(),filterObj);
 
                 // Make a client cursor from the runner.
-                new ClientCursor(ctx.ctx().db()->getCollection(ns()),
+                new ClientCursor(ctx.ctx().db()->getCollection(&_txn, ns()),
                                  ssr, 0, BSONObj());
 
                 // There should be one cursor before invalidation,
                 // and zero cursors after invalidation.
                 ASSERT_EQUALS(1U, numCursors());
-                ctx.ctx().db()->getCollection( ns() )->cursorCache()->invalidateAll(false);
+                ctx.ctx().db()->getCollection( &_txn, ns() )->cursorCache()->invalidateAll(false);
                 ASSERT_EQUALS(0U, numCursors());
             }
         };
@@ -369,7 +368,7 @@ namespace QuerySingleSolutionRunner {
                 Client::WriteContext ctx(&_txn, ns());
                 insert(BSON("a" << 1 << "b" << 1));
 
-                Collection* collection = ctx.ctx().db()->getCollection(ns());
+                Collection* collection = ctx.ctx().db()->getCollection(&_txn, ns());
 
                 BSONObj filterObj = fromjson("{_id: {$gt: 0}, b: {$gt: 0}}");
                 SingleSolutionRunner* ssr = makeCollScanRunner(ctx.ctx(),filterObj);
@@ -410,7 +409,7 @@ namespace QuerySingleSolutionRunner {
 
                 {
                     Client::ReadContext ctx(&_txn, ns());
-                    Collection* collection = ctx.ctx().db()->getCollection(ns());
+                    Collection* collection = ctx.ctx().db()->getCollection(&_txn, ns());
 
                     BSONObj filterObj = fromjson("{_id: {$gt: 0}, b: {$gt: 0}}");
                     SingleSolutionRunner* ssr = makeCollScanRunner(ctx.ctx(),filterObj);
diff --git a/src/mongo/dbtests/query_stage_and.cpp b/src/mongo/dbtests/query_stage_and.cpp
index f1d33ff7fb8..529476b94b1 100644
--- a/src/mongo/dbtests/query_stage_and.cpp
+++ b/src/mongo/dbtests/query_stage_and.cpp
@@ -130,7 +130,7 @@ namespace QueryStageAnd {
             Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
-            Collection* coll = db->getCollection(ns());
+            Collection* coll = db->getCollection(&txn, ns());
             if (!coll) {
                 coll = db->createCollection(&_txn, ns());
             }
@@ -232,7 +232,7 @@ namespace QueryStageAnd {
             Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
-            Collection* coll = db->getCollection(ns());
+            Collection* coll = db->getCollection(&txn, ns());
             if (!coll) {
                 coll = db->createCollection(&_txn, ns());
             }
@@ -318,7 +318,7 @@ namespace QueryStageAnd {
             Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
-            Collection* coll = db->getCollection(ns());
+            Collection* coll = db->getCollection(&txn, ns());
             if (!coll) {
                 coll = db->createCollection(&_txn, ns());
             }
@@ -367,7 +367,7 @@ namespace QueryStageAnd {
             Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
-            Collection* coll = db->getCollection(ns());
+            Collection* coll = db->getCollection(&txn, ns());
             if (!coll) {
                 coll = db->createCollection(&_txn, ns());
             }
@@ -419,7 +419,7 @@ namespace QueryStageAnd {
             Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
-            Collection* coll = db->getCollection(ns());
+            Collection* coll = db->getCollection(&txn, ns());
             if (!coll) {
                 coll = db->createCollection(&_txn, ns());
             }
@@ -470,7 +470,7 @@ namespace QueryStageAnd {
             Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
-            Collection* coll = db->getCollection(ns());
+            Collection* coll = db->getCollection(&txn, ns());
             if (!coll) {
                 coll = db->createCollection(&_txn, ns());
             }
@@ -531,7 +531,7 @@ namespace QueryStageAnd {
             Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
-            Collection* coll = db->getCollection(ns());
+            Collection* coll = db->getCollection(&txn, ns());
             if (!coll) {
                 coll = db->createCollection(&_txn, ns());
             }
@@ -590,7 +590,7 @@ namespace QueryStageAnd {
             Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
-            Collection* coll = db->getCollection(ns());
+            Collection* coll = db->getCollection(&txn, ns());
             if (!coll) {
                 coll = db->createCollection(&_txn, ns());
             }
@@ -649,7 +649,7 @@ namespace QueryStageAnd {
             Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
-            Collection* coll = db->getCollection(ns());
+            Collection* coll = db->getCollection(&txn, ns());
             if (!coll) {
                 coll = db->createCollection(&_txn, ns());
             }
@@ -697,7 +697,7 @@ namespace QueryStageAnd {
             Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
-            Collection* coll = db->getCollection(ns());
+            Collection* coll = db->getCollection(&txn, ns());
             if (!coll) {
                 coll = db->createCollection(&_txn, ns());
             }
@@ -753,7 +753,7 @@ namespace QueryStageAnd {
             Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
-            Collection* coll = db->getCollection(ns());
+            Collection* coll = db->getCollection(&txn, ns());
             if (!coll) {
                 coll = db->createCollection(&_txn, ns());
             }
@@ -870,7 +870,7 @@ namespace QueryStageAnd {
             Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
-            Collection* coll = db->getCollection(ns());
+            Collection* coll = db->getCollection(&txn, ns());
             if (!coll) {
                 coll = db->createCollection(&_txn, ns());
             }
@@ -923,7 +923,7 @@ namespace QueryStageAnd {
             Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
-            Collection* coll = db->getCollection(ns());
+            Collection* coll = db->getCollection(&txn, ns());
             if (!coll) {
                 coll = db->createCollection(&_txn, ns());
             }
@@ -968,7 +968,7 @@ namespace QueryStageAnd {
             Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
-            Collection* coll = db->getCollection(ns());
+            Collection* coll = db->getCollection(&txn, ns());
             if (!coll) {
                 coll = db->createCollection(&_txn, ns());
             }
@@ -1016,7 +1016,7 @@ namespace QueryStageAnd {
             Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
-            Collection* coll = db->getCollection(ns());
+            Collection* coll = db->getCollection(&txn, ns());
             if (!coll) {
                 coll = db->createCollection(&_txn, ns());
             }
@@ -1061,7 +1061,7 @@ namespace QueryStageAnd {
             Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
-            Collection* coll = db->getCollection(ns());
+            Collection* coll = db->getCollection(&txn, ns());
             if (!coll) {
                 coll = db->createCollection(&_txn, ns());
             }
diff --git a/src/mongo/dbtests/query_stage_collscan.cpp b/src/mongo/dbtests/query_stage_collscan.cpp
index fc30e82ad99..f1f6e33e9ed 100644
--- a/src/mongo/dbtests/query_stage_collscan.cpp
+++ b/src/mongo/dbtests/query_stage_collscan.cpp
@@ -162,7 +162,7 @@ namespace QueryStageCollectionScan {
 
         Database* db() { return _context.db(); }
         ExtentManager* extentManager() { return db()->getExtentManager(); }
-        Collection* collection() { return db()->getCollection( ns() ); }
+        Collection* collection() { return db()->getCollection( &_txn, ns() ); }
         NamespaceDetails *nsd() { return collection()->detailsWritable(); }
 
     protected:
@@ -338,7 +338,7 @@ namespace QueryStageCollectionScan {
 
             // Configure the scan.
             CollectionScanParams params;
-            params.collection = ctx.ctx().db()->getCollection( ns() );
+            params.collection = ctx.ctx().db()->getCollection( &_txn, ns() );
             params.direction = direction;
             params.tailable = false;
 
@@ -448,7 +448,7 @@ namespace QueryStageCollectionScan {
 
             // Configure the scan.
             CollectionScanParams params;
-            params.collection = ctx.ctx().db()->getCollection( ns() );
+            params.collection = ctx.ctx().db()->getCollection( &_txn, ns() );
             params.direction = CollectionScanParams::FORWARD;
             params.tailable = false;
 
@@ -478,7 +478,7 @@ namespace QueryStageCollectionScan {
             Client::ReadContext ctx(&_txn, ns());
 
             CollectionScanParams params;
-            params.collection = ctx.ctx().db()->getCollection( ns() );
+            params.collection = ctx.ctx().db()->getCollection( &_txn, ns() );
             params.direction = CollectionScanParams::BACKWARD;
             params.tailable = false;
 
@@ -506,7 +506,7 @@ namespace QueryStageCollectionScan {
         void run() {
             Client::WriteContext ctx(&_txn, ns());
 
-            Collection* coll = ctx.ctx().db()->getCollection( ns() );
+            Collection* coll = ctx.ctx().db()->getCollection( &_txn, ns() );
 
             // Get the DiskLocs that would be returned by an in-order scan.
             vector<DiskLoc> locs;
@@ -567,7 +567,7 @@ namespace QueryStageCollectionScan {
     public:
         void run() {
             Client::WriteContext ctx(&_txn, ns());
-            Collection* coll = ctx.ctx().db()->getCollection(ns());
+            Collection* coll = ctx.ctx().db()->getCollection(&_txn, ns());
 
             // Get the DiskLocs that would be returned by an in-order scan.
             vector<DiskLoc> locs;
diff --git a/src/mongo/dbtests/query_stage_count.cpp b/src/mongo/dbtests/query_stage_count.cpp
index 0d0dcbc0673..ac0e7e80705 100644
--- a/src/mongo/dbtests/query_stage_count.cpp
+++ b/src/mongo/dbtests/query_stage_count.cpp
@@ -87,7 +87,7 @@ namespace QueryStageCount {
         }
 
         IndexDescriptor* getIndex(Database* db, const BSONObj& obj) {
-            Collection* collection = db->getCollection(ns());
+            Collection* collection = db->getCollection(&_txn, ns());
             return collection->getIndexCatalog()->findIndexByKeyPattern(obj);
         }
 
diff --git a/src/mongo/dbtests/query_stage_distinct.cpp b/src/mongo/dbtests/query_stage_distinct.cpp
index ecbbbaf5561..c8799f73fcb 100644
--- a/src/mongo/dbtests/query_stage_distinct.cpp
+++ b/src/mongo/dbtests/query_stage_distinct.cpp
@@ -65,7 +65,7 @@ namespace QueryStageDistinct {
 
         IndexDescriptor* getIndex(const BSONObj& obj) {
             Client::ReadContext ctx(&_txn, ns());
-            Collection* collection = ctx.ctx().db()->getCollection( ns() );
+            Collection* collection = ctx.ctx().db()->getCollection( &_txn, ns() );
             return collection->getIndexCatalog()->findIndexByKeyPattern( obj );
         }
 
diff --git a/src/mongo/dbtests/query_stage_fetch.cpp b/src/mongo/dbtests/query_stage_fetch.cpp
index b99a95b1d87..5a97b5eb254 100644
--- a/src/mongo/dbtests/query_stage_fetch.cpp
+++ b/src/mongo/dbtests/query_stage_fetch.cpp
@@ -91,7 +91,7 @@ namespace QueryStageFetch {
             Client::WriteContext ctx(&txn, ns());
 
             Database* db = ctx.ctx().db();
-            Collection* coll = db->getCollection(ns());
+            Collection* coll = db->getCollection(&txn, ns());
             if (!coll) {
                 coll = db->createCollection(&txn, ns());
             }
@@ -150,7 +150,7 @@ namespace QueryStageFetch {
             Client::WriteContext ctx(&txn, ns());
 
             Database* db = ctx.ctx().db();
-            Collection* coll = db->getCollection(ns());
+            Collection* coll = db->getCollection(&txn, ns());
             if (!coll) {
                 coll = db->createCollection(&txn, ns());
             }
diff --git a/src/mongo/dbtests/query_stage_keep.cpp b/src/mongo/dbtests/query_stage_keep.cpp
index 5ea488a37f2..8df8f1a5f28 100644
--- a/src/mongo/dbtests/query_stage_keep.cpp
+++ b/src/mongo/dbtests/query_stage_keep.cpp
@@ -108,7 +108,7 @@ namespace QueryStageKeep {
             Client::WriteContext ctx(&txn, ns());
 
             Database* db = ctx.ctx().db();
-            Collection* coll = db->getCollection(ns());
+            Collection* coll = db->getCollection(&txn, ns());
             if (!coll) {
                 coll = db->createCollection(&txn, ns());
             }
diff --git a/src/mongo/dbtests/query_stage_merge_sort.cpp b/src/mongo/dbtests/query_stage_merge_sort.cpp
index 43319528bb2..ff52f9c6ffc 100644
--- a/src/mongo/dbtests/query_stage_merge_sort.cpp
+++ b/src/mongo/dbtests/query_stage_merge_sort.cpp
@@ -111,7 +111,7 @@ namespace QueryStageMergeSortTests {
             Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
-            Collection* coll = db->getCollection(ns());
+            Collection* coll = db->getCollection(&txn, ns());
             if (!coll) {
                 coll = db->createCollection(&_txn, ns());
             }
@@ -175,7 +175,7 @@ namespace QueryStageMergeSortTests {
             Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
-            Collection* coll = db->getCollection(ns());
+            Collection* coll = db->getCollection(&txn, ns());
             if (!coll) {
                 coll = db->createCollection(&_txn, ns());
             }
@@ -238,7 +238,7 @@ namespace QueryStageMergeSortTests {
             Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
-            Collection* coll = db->getCollection(ns());
+            Collection* coll = db->getCollection(&txn, ns());
             if (!coll) {
                 coll = db->createCollection(&_txn, ns());
             }
@@ -302,7 +302,7 @@ namespace QueryStageMergeSortTests {
             Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
-            Collection* coll = db->getCollection(ns());
+            Collection* coll = db->getCollection(&txn, ns());
             if (!coll) {
                 coll = db->createCollection(&_txn, ns());
             }
@@ -367,7 +367,7 @@ namespace QueryStageMergeSortTests {
             Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
-            Collection* coll = db->getCollection(ns());
+            Collection* coll = db->getCollection(&txn, ns());
             if (!coll) {
                 coll = db->createCollection(&_txn, ns());
             }
@@ -430,7 +430,7 @@ namespace QueryStageMergeSortTests {
             Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
-            Collection* coll = db->getCollection(ns());
+            Collection* coll = db->getCollection(&txn, ns());
             if (!coll) {
                 coll = db->createCollection(&_txn, ns());
             }
@@ -483,7 +483,7 @@ namespace QueryStageMergeSortTests {
             Client::WriteContext ctx(&_txn, ns());
             OperationContextImpl txn;
             Database* db = ctx.ctx().db();
-            Collection* coll = db->getCollection(ns());
+            Collection* coll = db->getCollection(&txn, ns());
             if (!coll) {
                 coll = db->createCollection(&_txn, ns());
             }
diff --git a/src/mongo/dbtests/query_stage_sort.cpp b/src/mongo/dbtests/query_stage_sort.cpp
index 2440f67948f..1d9b4806db3 100644
--- a/src/mongo/dbtests/query_stage_sort.cpp
+++ b/src/mongo/dbtests/query_stage_sort.cpp
@@ -183,7 +183,7 @@ namespace QueryStageSortTests {
             Client::WriteContext ctx(&txn, ns());
 
             Database* db = ctx.ctx().db();
-            Collection* coll = db->getCollection(ns());
+            Collection* coll = db->getCollection(&txn, ns());
             if (!coll) {
                 coll = db->createCollection(&txn, ns());
             }
@@ -203,7 +203,7 @@ namespace QueryStageSortTests {
             Client::WriteContext ctx(&txn, ns());
 
             Database* db = ctx.ctx().db();
-            Collection* coll = db->getCollection(ns());
+            Collection* coll = db->getCollection(&txn, ns());
             if (!coll) {
                 coll = db->createCollection(&txn, ns());
             }
@@ -232,7 +232,7 @@ namespace QueryStageSortTests {
             Client::WriteContext ctx(&txn, ns());
 
             Database* db = ctx.ctx().db();
-            Collection* coll = db->getCollection(ns());
+            Collection* coll = db->getCollection(&txn, ns());
             if (!coll) {
                 coll = db->createCollection(&txn, ns());
             }
@@ -252,7 +252,7 @@ namespace QueryStageSortTests {
             Client::WriteContext ctx(&txn, ns());
             
             Database* db = ctx.ctx().db();
-            Collection* coll = db->getCollection(ns());
+            Collection* coll = db->getCollection(&txn, ns());
             if (!coll) {
                 coll = db->createCollection(&txn, ns());
             }
@@ -343,7 +343,7 @@ namespace QueryStageSortTests {
             Client::WriteContext ctx(&txn, ns());
             
             Database* db = ctx.ctx().db();
-            Collection* coll = db->getCollection(ns());
+            Collection* coll = db->getCollection(&txn, ns());
             if (!coll) {
                 coll = db->createCollection(&txn, ns());
             }
diff --git a/src/mongo/dbtests/query_stage_tests.cpp b/src/mongo/dbtests/query_stage_tests.cpp
index 7e0b0f20c6e..23525ca265d 100644
--- a/src/mongo/dbtests/query_stage_tests.cpp
+++ b/src/mongo/dbtests/query_stage_tests.cpp
@@ -81,7 +81,7 @@ namespace QueryStageTests {
             WorkingSet* ws = new WorkingSet();
             PlanExecutor runner(ws, 
                                 new IndexScan(params, ws, filterExpr.get()), 
-                                ctx.ctx().db()->getCollection(ns()));
+                                ctx.ctx().db()->getCollection(&_txn, ns()));
 
             int count = 0;
             for (DiskLoc dl; Runner::RUNNER_ADVANCED == runner.getNext(NULL, &dl); ) {
@@ -103,7 +103,7 @@ namespace QueryStageTests {
 
         IndexDescriptor* getIndex(const BSONObj& obj) {
             Client::ReadContext ctx(&_txn, ns());
-            Collection* collection = ctx.ctx().db()->getCollection( ns() );
+            Collection* collection = ctx.ctx().db()->getCollection( &_txn, ns() );
             return collection->getIndexCatalog()->findIndexByKeyPattern( obj );
         }
 
diff --git a/src/mongo/dbtests/querytests.cpp b/src/mongo/dbtests/querytests.cpp
index 0e73c01e3b5..2fe15ba0741 100644
--- a/src/mongo/dbtests/querytests.cpp
+++ b/src/mongo/dbtests/querytests.cpp
@@ -62,7 +62,7 @@ namespace QueryTests {
     public:
         Base() : _context( ns() ) {
             _database = _context.db();
-            _collection = _database->getCollection( ns() );
+            _collection = _database->getCollection( &_txn, ns() );
             if ( _collection ) {
                 _database->dropCollection( &_txn, ns() );
             }
@@ -118,10 +118,10 @@ namespace QueryTests {
             BSONObj query = fromjson( "{$or:[{b:2},{c:3}]}" );
             BSONObj ret;
             // Check findOne() returning object.
-            ASSERT( Helpers::findOne( _collection, query, ret, true ) );
+            ASSERT( Helpers::findOne( &_txn, _collection, query, ret, true ) );
             ASSERT_EQUALS( string( "b" ), ret.firstElement().fieldName() );
             // Cross check with findOne() returning location.
-            ASSERT_EQUALS(ret, _collection->docFor(Helpers::findOne(_collection, query, true)));
+            ASSERT_EQUALS(ret, _collection->docFor(Helpers::findOne(&_txn, _collection, query, true)));
         }
     };
     
@@ -133,20 +133,20 @@ namespace QueryTests {
             BSONObj ret;
 
             // Check findOne() returning object, allowing unindexed scan.
-            ASSERT( Helpers::findOne( _collection, query, ret, false ) );
+            ASSERT( Helpers::findOne( &_txn, _collection, query, ret, false ) );
             // Check findOne() returning location, allowing unindexed scan.
-            ASSERT_EQUALS(ret, _collection->docFor(Helpers::findOne(_collection, query, false)));
+            ASSERT_EQUALS(ret, _collection->docFor(Helpers::findOne(&_txn, _collection, query, false)));
             
             // Check findOne() returning object, requiring indexed scan without index.
-            ASSERT_THROWS( Helpers::findOne( _collection, query, ret, true ), MsgAssertionException );
+            ASSERT_THROWS( Helpers::findOne( &_txn, _collection, query, ret, true ), MsgAssertionException );
             // Check findOne() returning location, requiring indexed scan without index.
-            ASSERT_THROWS( Helpers::findOne( _collection, query, true ), MsgAssertionException );
+            ASSERT_THROWS( Helpers::findOne( &_txn, _collection, query, true ), MsgAssertionException );
 
             addIndex( BSON( "b" << 1 ) );
             // Check findOne() returning object, requiring indexed scan with index.
-            ASSERT( Helpers::findOne( _collection, query, ret, true ) );
+            ASSERT( Helpers::findOne( &_txn, _collection, query, ret, true ) );
             // Check findOne() returning location, requiring indexed scan with index.
-            ASSERT_EQUALS(ret, _collection->docFor(Helpers::findOne(_collection, query, true)));
+            ASSERT_EQUALS(ret, _collection->docFor(Helpers::findOne(&_txn, _collection, query, true)));
         }
     };
     
@@ -159,7 +159,7 @@ namespace QueryTests {
             Client::Context ctx( "unittests.querytests" );
 
             Database* db = ctx.db();
-            if ( db->getCollection( ns() ) ) {
+            if ( db->getCollection( &_txn, ns() ) ) {
                 _collection = NULL;
                 db->dropCollection( &_txn, ns() );
             }
@@ -174,9 +174,9 @@ namespace QueryTests {
             insert( BSONObj() );
             BSONObj query;
             BSONObj ret;
-            ASSERT( Helpers::findOne( _collection, query, ret, false ) );
+            ASSERT( Helpers::findOne( &_txn, _collection, query, ret, false ) );
             ASSERT( ret.isEmpty() );
-            ASSERT_EQUALS(ret, _collection->docFor(Helpers::findOne(_collection, query, false)));
+            ASSERT_EQUALS(ret, _collection->docFor(Helpers::findOne(&_txn, _collection, query, false)));
         }
     };
     
@@ -244,7 +244,7 @@ namespace QueryTests {
                 // Check internal server handoff to getmore.
                 Lock::DBWrite lk(_txn.lockState(), ns);
                 Client::Context ctx( ns );
-                ClientCursorPin clientCursor( ctx.db()->getCollection(ns), cursorId );
+                ClientCursorPin clientCursor( ctx.db()->getCollection(&_txn, ns), cursorId );
                 // pq doesn't exist if it's a runner inside of the clientcursor.
                 // ASSERT( clientCursor.c()->pq );
                 // ASSERT_EQUALS( 2, clientCursor.c()->pq->getNumToReturn() );
@@ -301,7 +301,7 @@ namespace QueryTests {
             // Check that the cursor has been removed.
             {
                 Client::ReadContext ctx(&_txn, ns);
-                ASSERT( 0 == ctx.ctx().db()->getCollection( ns )->cursorCache()->numCursors() );
+                ASSERT(0 == ctx.ctx().db()->getCollection(&_txn, ns)->cursorCache()->numCursors());
             }
 
             ASSERT_FALSE(CollectionCursorCache::eraseCursorGlobal(&_txn, cursorId));
@@ -351,8 +351,8 @@ namespace QueryTests {
             // Check that the cursor still exists
             {
                 Client::ReadContext ctx(&_txn, ns);
-                ASSERT( 1 == ctx.ctx().db()->getCollection( ns )->cursorCache()->numCursors() );
-                ASSERT( ctx.ctx().db()->getCollection( ns )->cursorCache()->find( cursorId, false ) );
+                ASSERT( 1 == ctx.ctx().db()->getCollection( &_txn, ns )->cursorCache()->numCursors() );
+                ASSERT( ctx.ctx().db()->getCollection( &_txn, ns )->cursorCache()->find( cursorId, false ) );
             }
 
             // Check that the cursor can be iterated until all documents are returned.
@@ -612,7 +612,7 @@ namespace QueryTests {
             ASSERT_EQUALS( two, c->next()["ts"].Date() );
             long long cursorId = c->getCursorId();
             
-            ClientCursorPin clientCursor( ctx.db()->getCollection( ns ), cursorId );
+            ClientCursorPin clientCursor( ctx.db()->getCollection( &_txn, ns ), cursorId );
             ASSERT_EQUALS( three.millis, clientCursor.c()->getSlaveReadTill().asDate() );
         }
     };
@@ -1138,7 +1138,7 @@ namespace QueryTests {
 
         size_t numCursorsOpen() {
             Client::ReadContext ctx(&_txn, _ns);
-            Collection* collection = ctx.ctx().db()->getCollection( _ns );
+            Collection* collection = ctx.ctx().db()->getCollection( &_txn, _ns );
             if ( !collection )
                 return 0;
             return collection->cursorCache()->numCursors();
@@ -1237,14 +1237,14 @@ namespace QueryTests {
             ASSERT_EQUALS( 50 , count() );
 
             BSONObj res;
-            ASSERT( Helpers::findOne( ctx.ctx().db()->getCollection( ns() ),
+            ASSERT( Helpers::findOne( &_txn, ctx.ctx().db()->getCollection( &_txn, ns() ),
                                       BSON( "_id" << 20 ) , res , true ) );
             ASSERT_EQUALS( 40 , res["x"].numberInt() );
 
-            ASSERT( Helpers::findById( ctx.ctx().db(), ns() , BSON( "_id" << 20 ) , res ) );
+            ASSERT( Helpers::findById( &_txn, ctx.ctx().db(), ns() , BSON( "_id" << 20 ) , res ) );
             ASSERT_EQUALS( 40 , res["x"].numberInt() );
 
-            ASSERT( ! Helpers::findById( ctx.ctx().db(), ns() , BSON( "_id" << 200 ) , res ) );
+            ASSERT( ! Helpers::findById( &_txn, ctx.ctx().db(), ns() , BSON( "_id" << 200 ) , res ) );
 
             long long slow;
             long long fast;
@@ -1254,7 +1254,7 @@ namespace QueryTests {
             {
                 Timer t;
                 for ( int i=0; i<n; i++ ) {
-                    ASSERT( Helpers::findOne( ctx.ctx().db()->getCollection(ns()),
+                    ASSERT( Helpers::findOne( &_txn, ctx.ctx().db()->getCollection(&_txn, ns()),
                                               BSON( "_id" << 20 ), res, true ) );
                 }
                 slow = t.micros();
@@ -1262,7 +1262,7 @@ namespace QueryTests {
             {
                 Timer t;
                 for ( int i=0; i<n; i++ ) {
-                    ASSERT( Helpers::findById( ctx.ctx().db(), ns() , BSON( "_id" << 20 ) , res ) );
+                    ASSERT( Helpers::findById( &_txn, ctx.ctx().db(), ns() , BSON( "_id" << 20 ) , res ) );
                 }
                 fast = t.micros();
             }
@@ -1290,7 +1290,7 @@ namespace QueryTests {
 
             BSONObj res;
             for ( int i=0; i<1000; i++ ) {
-                bool found = Helpers::findById( ctx.ctx().db(), ns() , BSON( "_id" << i ) , res );
+                bool found = Helpers::findById( &_txn, ctx.ctx().db(), ns() , BSON( "_id" << i ) , res );
                 ASSERT_EQUALS( i % 2 , int(found) );
             }
 
@@ -1463,7 +1463,7 @@ namespace QueryTests {
             ClientCursor *clientCursor = 0;
             {
                 Client::ReadContext ctx(&_txn, ns());
-                ClientCursorPin clientCursorPointer( ctx.ctx().db()->getCollection( ns() ),
+                ClientCursorPin clientCursorPointer( ctx.ctx().db()->getCollection( &_txn, ns() ),
                                                      cursorId );
                 clientCursor = clientCursorPointer.c();
                 // clientCursorPointer destructor unpins the cursor.
@@ -1501,7 +1501,7 @@ namespace QueryTests {
             
             {
                 Client::WriteContext ctx(&_txn,  ns() );
-                ClientCursorPin pinCursor( ctx.ctx().db()->getCollection( ns() ), cursorId );
+                ClientCursorPin pinCursor( ctx.ctx().db()->getCollection( &_txn, ns() ), cursorId );
  
                 ASSERT_THROWS(CollectionCursorCache::eraseCursorGlobal(&_txn, cursorId),
                               MsgAssertionException);
diff --git a/src/mongo/dbtests/replsettests.cpp b/src/mongo/dbtests/replsettests.cpp
index deb82f41e17..d7c1c11b7f9 100644
--- a/src/mongo/dbtests/replsettests.cpp
+++ b/src/mongo/dbtests/replsettests.cpp
@@ -152,7 +152,7 @@ namespace ReplSetTests {
             Client::Context ctx(ns());
             
             Database* db = ctx.db();
-            Collection* coll = db->getCollection(ns());
+            Collection* coll = db->getCollection(&txn, ns());
             if (!coll) {
                 coll = db->createCollection(&txn, ns());
             }
@@ -180,7 +180,7 @@ namespace ReplSetTests {
 
             Database* db = c.ctx().db();
 
-            if ( db->getCollection( ns() ) == NULL ) {
+            if ( db->getCollection( &txn, ns() ) == NULL ) {
                 return;
             }
 
@@ -391,35 +391,36 @@ namespace ReplSetTests {
             verify(apply(b.obj()));
         }
 
-        void insert() {
+        void insert(OperationContext* txn) {
             Client::Context ctx(cappedNs());
-            OperationContextImpl txn;
             Database* db = ctx.db();
-            Collection* coll = db->getCollection(&txn, cappedNs());
+            Collection* coll = db->getCollection(txn, cappedNs());
             if (!coll) {
-                coll = db->createCollection(&txn, cappedNs());
+                coll = db->createCollection(txn, cappedNs());
             }
 
             BSONObj o = BSON(GENOID << "x" << 456);
-            DiskLoc loc = coll->insertDocument(&txn, o, true).getValue();
+            DiskLoc loc = coll->insertDocument(txn, o, true).getValue();
             verify(!loc.isNull());
         }
     public:
         virtual ~CappedUpdate() {}
         void run() {
+            OperationContextImpl txn;
+
             // RARELY shoud be once/128x
             for (int i=0; i<150; i++) {
-                insert();
+                insert(&txn);
                 updateSucceed();
             }
 
-            DBDirectClient client;
+            DBDirectClient client(&txn);
             int count = (int) client.count(cappedNs(), BSONObj());
             verify(count > 1);
 
             // check _id index created
             Client::Context ctx(cappedNs());
-            Collection* collection = ctx.db()->getCollection( cappedNs() );
+            Collection* collection = ctx.db()->getCollection( &txn, cappedNs() );
             verify(collection->getIndexCatalog()->findIdIndex());
         }
     };
@@ -438,6 +439,7 @@ namespace ReplSetTests {
     public:
         virtual ~CappedInsert() {}
         void run() {
+            OperationContextImpl txn;
             // This will succeed, but not insert anything because they are changed to upserts
             for (int i=0; i<150; i++) {
                 insertSucceed();
@@ -446,7 +448,7 @@ namespace ReplSetTests {
             // this changed in 2.1.2
             // we now have indexes on capped collections
             Client::Context ctx(cappedNs());
-            Collection* collection = ctx.db()->getCollection( cappedNs() );
+            Collection* collection = ctx.db()->getCollection( &txn, cappedNs() );
             verify(collection->getIndexCatalog()->findIdIndex());
         }
     };
diff --git a/src/mongo/dbtests/repltests.cpp b/src/mongo/dbtests/repltests.cpp
index e76ebd3c6eb..906d4990766 100644
--- a/src/mongo/dbtests/repltests.cpp
+++ b/src/mongo/dbtests/repltests.cpp
@@ -57,7 +57,6 @@ namespace ReplTests {
     class Base {
         Lock::GlobalWrite lk;
         Client::Context _context;
-        mutable OperationContextImpl _txn;
     public:
         Base() : _context( ns() ) {
             oldRepl();
@@ -66,7 +65,7 @@ namespace ReplTests {
             replSettings.master = true;
             createOplog();
 
-            Collection* c = _context.db()->getCollection( ns() );
+            Collection* c = _context.db()->getCollection( &_txn, ns() );
             if ( ! c ) {
                 c = _context.db()->createCollection( &_txn, ns() );
             }
@@ -136,7 +135,7 @@ namespace ReplTests {
             Client::Context ctx( cllNS() );
             OperationContextImpl txn;
             Database* db = ctx.db();
-            Collection* coll = db->getCollection( cllNS() );
+            Collection* coll = db->getCollection( &txn, cllNS() );
             if ( !coll ) {
                 coll = db->createCollection( &txn, cllNS() );
             }
@@ -157,7 +156,7 @@ namespace ReplTests {
             {
                 Client::Context ctx( cllNS() );
                 Database* db = ctx.db();
-                Collection* coll = db->getCollection( cllNS() );
+                Collection* coll = db->getCollection( &txn, cllNS() );
 
                 RecordIterator* it = coll->getIterator( DiskLoc(), false,
                                                             CollectionScanParams::FORWARD );
@@ -186,7 +185,7 @@ namespace ReplTests {
             Client::Context ctx( ns );
             OperationContextImpl txn;
             Database* db = ctx.db();
-            Collection* coll = db->getCollection( ns );
+            Collection* coll = db->getCollection( &txn, ns );
             if ( !coll ) {
                 coll = db->createCollection( &txn, ns );
             }
@@ -206,7 +205,7 @@ namespace ReplTests {
             Client::Context ctx( ns );
             OperationContextImpl txn;
             Database* db = ctx.db();
-            Collection* coll = db->getCollection( ns );
+            Collection* coll = db->getCollection( &txn, ns );
             if ( !coll ) {
                 coll = db->createCollection( &txn, ns );
             }
@@ -227,7 +226,7 @@ namespace ReplTests {
             Client::Context ctx( ns() );
             OperationContextImpl txn;
             Database* db = ctx.db();
-            Collection* coll = db->getCollection( ns() );
+            Collection* coll = db->getCollection( &txn, ns() );
             if ( !coll ) {
                 coll = db->createCollection( &txn, ns() );
             }
@@ -255,6 +254,8 @@ namespace ReplTests {
         Database* db() {
             return _context.db();
         }
+
+        mutable OperationContextImpl _txn;
     private:
         static DBDirectClient client_;
     };
@@ -1395,7 +1396,7 @@ namespace ReplTests {
         bool returnEmpty;
         SyncTest() : Sync(""), returnEmpty(false) {}
         virtual ~SyncTest() {}
-        virtual BSONObj getMissingDoc(Database* db, const BSONObj& o) {
+        virtual BSONObj getMissingDoc(OperationContext* txn, Database* db, const BSONObj& o) {
             if (returnEmpty) {
                 BSONObj o;
                 return o;
@@ -1413,7 +1414,7 @@ namespace ReplTests {
             // this should fail because we can't connect
             try {
                 Sync badSource("localhost:123");
-                badSource.getMissingDoc(db(), o);
+                badSource.getMissingDoc(&_txn, db(), o);
             }
             catch (DBException&) {
                 threw = true;
diff --git a/src/mongo/dbtests/runner_registry.cpp b/src/mongo/dbtests/runner_registry.cpp
index b29088e36d8..8f197a5c552 100644
--- a/src/mongo/dbtests/runner_registry.cpp
+++ b/src/mongo/dbtests/runner_registry.cpp
@@ -74,23 +74,24 @@ namespace RunnerRegistry {
             CanonicalQuery* cq;
             ASSERT(CanonicalQuery::canonicalize(ns(), BSONObj(), &cq).isOK());
             // Owns all args
-            auto_ptr<Runner> run(new SingleSolutionRunner(_ctx->ctx().db()->getCollection( ns() ),
+            auto_ptr<Runner> run(new SingleSolutionRunner(_ctx->ctx().db()->getCollection( &_opCtx,
+                                                                                           ns() ),
                                                           cq, NULL, scan.release(), ws.release()));
             return run.release();
         }
 
         void registerRunner( Runner* runner ) {
-            _ctx->ctx().db()->getOrCreateCollection( ns() )->cursorCache()->registerRunner( runner );
+            _ctx->ctx().db()->getOrCreateCollection( &_opCtx, ns() )->cursorCache()->registerRunner( runner );
         }
 
         void deregisterRunner( Runner* runner ) {
-            _ctx->ctx().db()->getOrCreateCollection( ns() )->cursorCache()->deregisterRunner( runner );
+            _ctx->ctx().db()->getOrCreateCollection( &_opCtx, ns() )->cursorCache()->deregisterRunner( runner );
         }
 
         int N() { return 50; }
 
         Collection* collection() {
-            return _ctx->ctx().db()->getCollection( ns() );
+            return _ctx->ctx().db()->getCollection( &_opCtx, ns() );
         }
 
         static const char* ns() { return "unittests.RunnerRegistryDiskLocInvalidation"; }
diff --git a/src/mongo/s/d_logic.h b/src/mongo/s/d_logic.h
index 668969517da..d23bc6f9c2e 100644
--- a/src/mongo/s/d_logic.h
+++ b/src/mongo/s/d_logic.h
@@ -42,6 +42,7 @@ namespace mongo {
 
     class Database;
     class DiskLoc;
+    class OperationContext;
 
     // --------------
     // --- global state ---
@@ -370,7 +371,8 @@ namespace mongo {
      * if it's relevant. The entries saved here are later transferred to the receiving side of
      * the migration. A relevant entry is an insertion, a deletion, or an update.
      */
-    void logOpForSharding( const char * opstr,
+    void logOpForSharding( OperationContext* txn,
+                           const char * opstr,
                            const char * ns,
                            const BSONObj& obj,
                            BSONObj * patt,
diff --git a/src/mongo/s/d_migrate.cpp b/src/mongo/s/d_migrate.cpp
index b041b4d4e5a..fbb06b79590 100644
--- a/src/mongo/s/d_migrate.cpp
+++ b/src/mongo/s/d_migrate.cpp
@@ -267,7 +267,8 @@ namespace mongo {
             _inCriticalSectionCV.notify_all();
         }
 
-        void logOp(const char* opstr,
+        void logOp(OperationContext* txn,
+                   const char* opstr,
                    const char* ns,
                    const BSONObj& obj,
                    BSONObj* patt,
@@ -321,7 +322,7 @@ namespace mongo {
 
             case 'u':
                 Client::Context ctx( _ns );
-                if ( ! Helpers::findById( ctx.db(), _ns.c_str(), ide.wrap(), it ) ) {
+                if ( ! Helpers::findById( txn, ctx.db(), _ns.c_str(), ide.wrap(), it ) ) {
                     warning() << "logOpForSharding couldn't find: " << ide << " even though should have" << migrateLog;
                     return;
                 }
@@ -336,7 +337,7 @@ namespace mongo {
             _memoryUsed += ide.size() + 5;
         }
 
-        void xfer( Database* db, list<BSONObj> * l , BSONObjBuilder& b , const char * name , long long& size , bool explode ) {
+        void xfer( OperationContext* txn, Database* db, list<BSONObj> * l , BSONObjBuilder& b , const char * name , long long& size , bool explode ) {
             const long long maxSize = 1024 * 1024;
 
             if ( l->size() == 0 || size > maxSize )
@@ -350,7 +351,7 @@ namespace mongo {
                 BSONObj t = *i;
                 if ( explode ) {
                     BSONObj it;
-                    if ( Helpers::findById( db , _ns.c_str() , t, it ) ) {
+                    if ( Helpers::findById( txn, db , _ns.c_str() , t, it ) ) {
                         arr.append( it );
                         size += it.objsize();
                     }
@@ -380,8 +381,8 @@ namespace mongo {
             {
                 Client::ReadContext cx(txn, _ns);
 
-                xfer( cx.ctx().db(), &_deleted, b, "deleted", size, false );
-                xfer( cx.ctx().db(), &_reload, b, "reload", size, true );
+                xfer( txn, cx.ctx().db(), &_deleted, b, "deleted", size, false );
+                xfer( txn, cx.ctx().db(), &_reload, b, "reload", size, true );
             }
 
             b.append( "size" , size );
@@ -401,7 +402,7 @@ namespace mongo {
                               string& errmsg,
                               BSONObjBuilder& result ) {
             Client::ReadContext ctx(txn, _ns);
-            Collection* collection = ctx.ctx().db()->getCollection( _ns );
+            Collection* collection = ctx.ctx().db()->getCollection( txn, _ns );
             if ( !collection ) {
                 errmsg = "ns not found, should be impossible";
                 return false;
@@ -491,7 +492,7 @@ namespace mongo {
             int allocSize;
             {
                 Client::ReadContext ctx(txn, _ns);
-                Collection* collection = ctx.ctx().db()->getCollection( _ns );
+                Collection* collection = ctx.ctx().db()->getCollection( txn, _ns );
                 verify( collection );
                 scoped_spinlock lk( _trackerLocks );
                 allocSize =
@@ -504,7 +505,7 @@ namespace mongo {
                 bool filledBuffer = false;
                 
                 Client::ReadContext ctx(txn, _ns);
-                Collection* collection = ctx.ctx().db()->getCollection( _ns );
+                Collection* collection = ctx.ctx().db()->getCollection( txn, _ns );
 
                 scoped_spinlock lk( _trackerLocks );
                 set<DiskLoc>::iterator i = _cloneLocs.begin();
@@ -629,7 +630,7 @@ namespace mongo {
                 if ( !_collection )
                     return;
                 Client::ReadContext ctx(_txn, _ns);
-                Collection* collection = ctx.ctx().db()->getCollection( _ns );
+                Collection* collection = ctx.ctx().db()->getCollection( _txn, _ns );
                 invariant( _collection == collection );
                 _collection->cursorCache()->deregisterRunner( this );
             }
@@ -699,12 +700,13 @@ namespace mongo {
         bool _isAnotherMigrationActive;
     };
 
-    void logOpForSharding(const char * opstr,
+    void logOpForSharding(OperationContext* txn,
+                          const char * opstr,
                           const char * ns,
                           const BSONObj& obj,
                           BSONObj * patt,
                           bool notInActiveChunk) {
-        migrateFromStatus.logOp(opstr, ns, obj, patt, notInActiveChunk);
+        migrateFromStatus.logOp(txn, opstr, ns, obj, patt, notInActiveChunk);
     }
 
     class TransferModsCommand : public ChunkCommandHelper {
@@ -1628,7 +1630,7 @@ namespace mongo {
                 Client::WriteContext ctx(txn,  ns );
                 // Only copy if ns doesn't already exist
                 Database* db = ctx.ctx().db();
-                Collection* collection = db->getCollection( ns );
+                Collection* collection = db->getCollection( txn, ns );
 
                 if ( !collection ) {
                     string system_namespaces = nsToDatabase(ns) + ".system.namespaces";
@@ -1759,7 +1761,7 @@ namespace mongo {
                             Client::WriteContext cx(txn, ns );
 
                             BSONObj localDoc;
-                            if ( willOverrideLocalId( cx.ctx().db(), o, &localDoc ) ) {
+                            if ( willOverrideLocalId( txn, cx.ctx().db(), o, &localDoc ) ) {
                                 string errMsg =
                                     str::stream() << "cannot migrate chunk, local document "
                                     << localDoc
@@ -1957,7 +1959,7 @@ namespace mongo {
 
                     // do not apply deletes if they do not belong to the chunk being migrated
                     BSONObj fullObj;
-                    if ( Helpers::findById( cx.ctx().db(), ns.c_str(), id, fullObj ) ) {
+                    if ( Helpers::findById( txn, cx.ctx().db(), ns.c_str(), id, fullObj ) ) {
                         if ( ! isInRange( fullObj , min , max , shardKeyPattern ) ) {
                             log() << "not applying out of range deletion: " << fullObj << migrateLog;
 
@@ -1991,7 +1993,7 @@ namespace mongo {
                     BSONObj it = i.next().Obj();
 
                     BSONObj localDoc;
-                    if ( willOverrideLocalId( cx.ctx().db(), it, &localDoc ) ) {
+                    if ( willOverrideLocalId( txn, cx.ctx().db(), it, &localDoc ) ) {
                         string errMsg =
                             str::stream() << "cannot migrate chunk, local document "
                                           << localDoc
@@ -2021,10 +2023,10 @@ namespace mongo {
          * Must be in WriteContext to avoid races and DBHelper errors.
          * TODO: Could optimize this check out if sharding on _id.
          */
-        bool willOverrideLocalId( Database* db, BSONObj remoteDoc, BSONObj* localDoc ) {
+        bool willOverrideLocalId( OperationContext* txn, Database* db, BSONObj remoteDoc, BSONObj* localDoc ) {
 
             *localDoc = BSONObj();
-            if ( Helpers::findById( db, ns.c_str(), remoteDoc, *localDoc ) ) {
+            if ( Helpers::findById( txn, db, ns.c_str(), remoteDoc, *localDoc ) ) {
                 return !isInRange( *localDoc , min , max , shardKeyPattern );
             }
 
diff --git a/src/mongo/s/d_split.cpp b/src/mongo/s/d_split.cpp
index 7bb1d4d82d7..f45585293c7 100644
--- a/src/mongo/s/d_split.cpp
+++ b/src/mongo/s/d_split.cpp
@@ -120,7 +120,7 @@ namespace mongo {
             }
 
             Client::ReadContext ctx(txn, ns);
-            Collection* collection = ctx.ctx().db()->getCollection( ns );
+            Collection* collection = ctx.ctx().db()->getCollection( txn, ns );
             if ( !collection ) {
                 errmsg = "ns not found";
                 return false;
@@ -276,7 +276,7 @@ namespace mongo {
             {
                 // Get the size estimate for this namespace
                 Client::ReadContext ctx(txn, ns);
-                Collection* collection = ctx.ctx().db()->getCollection( ns );
+                Collection* collection = ctx.ctx().db()->getCollection( txn, ns );
                 if ( !collection ) {
                     errmsg = "ns not found";
                     return false;
@@ -859,7 +859,7 @@ namespace mongo {
                 for (int i=1; i >= 0 ; i--){ // high chunk more likely to have only one obj
 
                     Client::ReadContext ctx(txn, ns);
-                    Collection* collection = ctx.ctx().db()->getCollection( ns );
+                    Collection* collection = ctx.ctx().db()->getCollection( txn, ns );
                     verify( collection );
 
                     // Allow multiKey based on the invariant that shard keys must be
diff --git a/src/mongo/tools/dump.cpp b/src/mongo/tools/dump.cpp
index f699e76585e..83382b6c1ff 100644
--- a/src/mongo/tools/dump.cpp
+++ b/src/mongo/tools/dump.cpp
@@ -301,8 +301,11 @@ public:
      * NOTE: The "outfile" parameter passed in should actually represent a directory, but it is
      * called "outfile" because we append the filename and use it as our output file.
      */
-    void _repair( Database* db , string ns , boost::filesystem::path outfile ){
-        Collection* collection = db->getCollection( ns );
+    void _repair(OperationContext* opCtx,
+                 Database* db,
+                 string ns,
+                 boost::filesystem::path outfile) {
+        Collection* collection = db->getCollection(opCtx, ns);
         toolInfoLog() << "nrecords: " << collection->numRecords()
                       << " datasize: " << collection->dataSize()
                       << std::endl;
@@ -363,7 +366,7 @@ public:
             
             LogIndentLevel lil1;
             try {
-                _repair( db , ns , root );
+                _repair( &txn, db , ns , root );
             }
             catch ( DBException& e ){
                 toolError() << "ERROR recovering: " << ns << " " << e.toString() << std::endl;