SERVER-37244 Move MongoD-specific code out of SessionCatalog

19 files changed, 250 insertions, 159 deletions

diff --git a/src/mongo/db/SConscript b/src/mongo/db/SConscript
index 202e70c044a..0f78df550db 100644
--- a/src/mongo/db/SConscript
+++ b/src/mongo/db/SConscript
@@ -643,24 +643,25 @@ env.Library(
         'operation_context_session_mongod.cpp',
         'retryable_writes_stats.cpp',
         'server_transactions_metrics.cpp',
-        'session.cpp',
+        'session_catalog_mongod.cpp',
         'session_catalog.cpp',
+        'session.cpp',
         'single_transaction_stats.cpp',
         'transaction_coordinator_factory.cpp',
+        'transaction_history_iterator.cpp',
         'transaction_metrics_observer.cpp',
         'transaction_participant.cpp',
-        'transaction_history_iterator.cpp',
         env.Idlc('session_txn_record.idl')[0],
-        env.Idlc('transactions_stats.idl')[0],
         env.Idlc('transaction_commit_decision.idl')[0],
+        env.Idlc('transactions_stats.idl')[0],
     ],
     LIBDEPS=[
-        '$BUILD_DIR/mongo/db/stats/fill_locker_info',
         '$BUILD_DIR/mongo/idl/idl_parser',
         'catalog/collection',
-        'catalog/database',
         'catalog/database_holder',
+        'catalog/database',
         'catalog/uuid_catalog',
+        'commands/test_commands_enabled',
         'commands/txn_cmd_request',
         'concurrency/lock_manager',
         'curop_failpoint_helpers',
@@ -673,9 +674,9 @@ env.Library(
         'repl/oplog_entry',
         'repl/oplog_shim',
         's/sharding_api_d',
-        "stats/top",
+        'stats/fill_locker_info',
         'views/views',
-        '$BUILD_DIR/mongo/db/commands/test_commands_enabled',
+        "stats/top",
     ],
     LIBDEPS_PRIVATE=[
         'commands/server_status',
@@ -1960,15 +1961,14 @@ env.Library(
 )
 
 env.CppUnitTest(
-    target='sessions_test',
+    target='session_catalog_test',
     source=[
         'session_catalog_test.cpp',
     ],
     LIBDEPS=[
-        '$BUILD_DIR/mongo/client/read_preference',
-        '$BUILD_DIR/mongo/db/auth/authmocks',
-        '$BUILD_DIR/mongo/db/repl/mock_repl_coord_server_fixture',
-        'query_exec',
+        'auth/authmocks',
+        'catalog_raii',
+        'repl/mock_repl_coord_server_fixture',
     ],
 )
 
diff --git a/src/mongo/db/kill_sessions_local.cpp b/src/mongo/db/kill_sessions_local.cpp
index e76b2b8db65..99efaa2e91d 100644
--- a/src/mongo/db/kill_sessions_local.cpp
+++ b/src/mongo/db/kill_sessions_local.cpp
@@ -37,27 +37,37 @@
 #include "mongo/db/kill_sessions_common.h"
 #include "mongo/db/operation_context.h"
 #include "mongo/db/service_context.h"
-#include "mongo/db/session.h"
 #include "mongo/db/session_catalog.h"
+#include "mongo/db/session_killer.h"
 #include "mongo/db/transaction_participant.h"
 #include "mongo/util/log.h"
 
 namespace mongo {
 namespace {
-void killSessionsLocalKillCursors(OperationContext* opCtx, const SessionKiller::Matcher& matcher) {
 
-    auto res = CursorManager::killCursorsWithMatchingSessions(opCtx, matcher);
-    uassertStatusOK(res.first);
+void killSessionsAction(OperationContext* opCtx,
+                        const SessionKiller::Matcher& matcher,
+                        const SessionCatalog::ScanSessionsCallbackFn& killSessionFn) {
+    const auto catalog = SessionCatalog::get(opCtx);
+
+    catalog->scanSessions(opCtx, matcher, [&](OperationContext* opCtx, Session* session) {
+        // TODO (SERVER-33850): Rename KillAllSessionsByPattern and
+        // ScopedKillAllSessionsByPatternImpersonator to not refer to session kill
+        const KillAllSessionsByPattern* pattern = matcher.match(session->getSessionId());
+        invariant(pattern);
+
+        ScopedKillAllSessionsByPatternImpersonator impersonator(opCtx, *pattern);
+        killSessionFn(opCtx, session);
+    });
 }
+
 }  // namespace
 
 void killSessionsLocalKillTransactions(OperationContext* opCtx,
                                        const SessionKiller::Matcher& matcher) {
-    SessionCatalog::get(opCtx)->scanSessions(
-        opCtx, matcher, [](OperationContext* opCtx, Session* session) {
-            TransactionParticipant::getFromNonCheckedOutSession(session)
-                ->abortArbitraryTransaction();
-        });
+    killSessionsAction(opCtx, matcher, [](OperationContext* opCtx, Session* session) {
+        TransactionParticipant::getFromNonCheckedOutSession(session)->abortArbitraryTransaction();
+    });
 }
 
 SessionKiller::Result killSessionsLocal(OperationContext* opCtx,
@@ -65,43 +75,44 @@ SessionKiller::Result killSessionsLocal(OperationContext* opCtx,
                                         SessionKiller::UniformRandomBitGenerator* urbg) {
     killSessionsLocalKillTransactions(opCtx, matcher);
     uassertStatusOK(killSessionsLocalKillOps(opCtx, matcher));
-    killSessionsLocalKillCursors(opCtx, matcher);
+
+    auto res = CursorManager::killCursorsWithMatchingSessions(opCtx, matcher);
+    uassertStatusOK(res.first);
+
     return {std::vector<HostAndPort>{}};
 }
 
 void killAllExpiredTransactions(OperationContext* opCtx) {
     SessionKiller::Matcher matcherAllSessions(
         KillAllSessionsByPatternSet{makeKillAllSessionsByPattern(opCtx)});
-    SessionCatalog::get(opCtx)->scanSessions(
-        opCtx, matcherAllSessions, [](OperationContext* opCtx, Session* session) {
-            try {
-                TransactionParticipant::getFromNonCheckedOutSession(session)
-                    ->abortArbitraryTransactionIfExpired();
-            } catch (const DBException& ex) {
-                Status status = ex.toStatus();
-                std::string errmsg = str::stream()
-                    << "May have failed to abort expired transaction with session id (lsid) '"
-                    << session->getSessionId() << "'."
-                    << " Caused by: " << status;
-                warning() << errmsg;
-            }
-        });
+    killSessionsAction(opCtx, matcherAllSessions, [](OperationContext* opCtx, Session* session) {
+        try {
+            TransactionParticipant::getFromNonCheckedOutSession(session)
+                ->abortArbitraryTransactionIfExpired();
+        } catch (const DBException& ex) {
+            Status status = ex.toStatus();
+            std::string errmsg = str::stream()
+                << "May have failed to abort expired transaction with session id (lsid) '"
+                << session->getSessionId() << "'."
+                << " Caused by: " << status;
+            warning() << errmsg;
+        }
+    });
 }
 
 void killSessionsLocalShutdownAllTransactions(OperationContext* opCtx) {
     SessionKiller::Matcher matcherAllSessions(
         KillAllSessionsByPatternSet{makeKillAllSessionsByPattern(opCtx)});
-    SessionCatalog::get(opCtx)->scanSessions(
-        opCtx, matcherAllSessions, [](OperationContext* opCtx, Session* session) {
-            TransactionParticipant::getFromNonCheckedOutSession(session)->shutdown();
-        });
+    killSessionsAction(opCtx, matcherAllSessions, [](OperationContext* opCtx, Session* session) {
+        TransactionParticipant::getFromNonCheckedOutSession(session)->shutdown();
+    });
 }
 
 void killSessionsLocalAbortOrYieldAllTransactions(
     OperationContext* opCtx, std::vector<std::pair<Locker*, Locker::LockSnapshot>>* yieldedLocks) {
     SessionKiller::Matcher matcherAllSessions(
         KillAllSessionsByPatternSet{makeKillAllSessionsByPattern(opCtx)});
-    SessionCatalog::get(opCtx)->scanSessions(
+    killSessionsAction(
         opCtx, matcherAllSessions, [yieldedLocks](OperationContext* opCtx, Session* session) {
             TransactionParticipant::getFromNonCheckedOutSession(session)
                 ->abortOrYieldArbitraryTransaction(yieldedLocks);
diff --git a/src/mongo/db/op_observer_impl_test.cpp b/src/mongo/db/op_observer_impl_test.cpp
index c5d202cee71..f6cb972a78e 100644
--- a/src/mongo/db/op_observer_impl_test.cpp
+++ b/src/mongo/db/op_observer_impl_test.cpp
@@ -26,8 +26,8 @@
  *    it in the license file.
  */
 
+#include "mongo/platform/basic.h"
 
-#include "mongo/db/op_observer_impl.h"
 #include "mongo/db/auth/authorization_manager.h"
 #include "mongo/db/client.h"
 #include "mongo/db/concurrency/locker_noop.h"
@@ -37,13 +37,14 @@
 #include "mongo/db/keys_collection_manager.h"
 #include "mongo/db/logical_clock.h"
 #include "mongo/db/logical_time_validator.h"
+#include "mongo/db/op_observer_impl.h"
 #include "mongo/db/operation_context_session_mongod.h"
 #include "mongo/db/repl/oplog.h"
 #include "mongo/db/repl/oplog_interface_local.h"
 #include "mongo/db/repl/repl_client_info.h"
 #include "mongo/db/repl/replication_coordinator_mock.h"
 #include "mongo/db/service_context_d_test_fixture.h"
-#include "mongo/db/session_catalog.h"
+#include "mongo/db/session_catalog_mongod.h"
 #include "mongo/db/storage/ephemeral_for_test/ephemeral_for_test_recovery_unit.h"
 #include "mongo/db/transaction_participant.h"
 #include "mongo/s/config_server_test_fixture.h"
@@ -301,9 +302,15 @@ public:
     void setUp() override {
         OpObserverTest::setUp();
         auto opCtx = cc().makeOperationContext();
+
+        MongoDSessionCatalog::onStepUp(opCtx.get());
+    }
+
+    void tearDown() override {
         auto sessionCatalog = SessionCatalog::get(getServiceContext());
         sessionCatalog->reset_forTest();
-        sessionCatalog->onStepUp(opCtx.get());
+
+        OpObserverTest::tearDown();
     }
 
     /**
diff --git a/src/mongo/db/repl/SConscript b/src/mongo/db/repl/SConscript
index 8465cd9f70b..5c0f5e5e36d 100644
--- a/src/mongo/db/repl/SConscript
+++ b/src/mongo/db/repl/SConscript
@@ -129,8 +129,6 @@ env.Library(
     ],
 )
 
-
-
 env.Library(
     target='bgsync',
     source=[
diff --git a/src/mongo/db/repl/do_txn_test.cpp b/src/mongo/db/repl/do_txn_test.cpp
index 91642f9f951..2bd573e78e1 100644
--- a/src/mongo/db/repl/do_txn_test.cpp
+++ b/src/mongo/db/repl/do_txn_test.cpp
@@ -25,6 +25,7 @@
  * delete this exception statement from all source files in the program,
  * then also delete it in the license file.
  */
+
 #include "mongo/platform/basic.h"
 
 #include "mongo/db/catalog/collection_options.h"
@@ -40,7 +41,7 @@
 #include "mongo/db/repl/storage_interface_impl.h"
 #include "mongo/db/s/op_observer_sharding_impl.h"
 #include "mongo/db/service_context_d_test_fixture.h"
-#include "mongo/db/session_catalog.h"
+#include "mongo/db/session_catalog_mongod.h"
 #include "mongo/db/transaction_participant.h"
 #include "mongo/logger/logger.h"
 #include "mongo/rpc/get_status_from_command_result.h"
@@ -121,7 +122,7 @@ void DoTxnTest::setUp() {
     // Set up mongod.
     ServiceContextMongoDTest::setUp();
 
-    auto service = getServiceContext();
+    const auto service = getServiceContext();
     _opCtx = cc().makeOperationContext();
 
     // Set up ReplicationCoordinator and create oplog.
@@ -134,8 +135,7 @@ void DoTxnTest::setUp() {
     ASSERT_OK(replCoord->setFollowerMode(MemberState::RS_PRIMARY));
 
     // Set up session catalog
-    SessionCatalog::get(service)->reset_forTest();
-    SessionCatalog::get(service)->onStepUp(_opCtx.get());
+    MongoDSessionCatalog::onStepUp(_opCtx.get());
 
     // Need the OpObserverImpl in the registry in order for doTxn to work.
     OpObserverRegistry* opObserverRegistry =
@@ -166,6 +166,8 @@ void DoTxnTest::tearDown() {
     _storage = {};
     _opObserver = nullptr;
 
+    SessionCatalog::get(getServiceContext())->reset_forTest();
+
     // Reset default log level in case it was changed.
     logger::globalLogDomain()->setMinimumLoggedSeverity(logger::LogComponent::kReplication,
                                                         logger::LogSeverity::Debug(0));
diff --git a/src/mongo/db/repl/replication_coordinator_external_state_impl.cpp b/src/mongo/db/repl/replication_coordinator_external_state_impl.cpp
index 3af514b94e4..8e7934e2912 100644
--- a/src/mongo/db/repl/replication_coordinator_external_state_impl.cpp
+++ b/src/mongo/db/repl/replication_coordinator_external_state_impl.cpp
@@ -78,7 +78,7 @@
 #include "mongo/db/server_options.h"
 #include "mongo/db/server_parameters.h"
 #include "mongo/db/service_context.h"
-#include "mongo/db/session_catalog.h"
+#include "mongo/db/session_catalog_mongod.h"
 #include "mongo/db/storage/storage_engine.h"
 #include "mongo/db/system_index.h"
 #include "mongo/executor/network_connection_hook.h"
@@ -95,7 +95,6 @@
 #include "mongo/stdx/memory.h"
 #include "mongo/stdx/thread.h"
 #include "mongo/transport/service_entry_point.h"
-#include "mongo/transport/session.h"
 #include "mongo/util/assert_util.h"
 #include "mongo/util/concurrency/thread_pool.h"
 #include "mongo/util/exit.h"
@@ -779,7 +778,7 @@ void ReplicationCoordinatorExternalStateImpl::_shardingOnTransitionToPrimaryHook
         }
     }
 
-    SessionCatalog::get(_service)->onStepUp(opCtx);
+    MongoDSessionCatalog::onStepUp(opCtx);
 
     notifyFreeMonitoringOnTransitionToPrimary();
 }
diff --git a/src/mongo/db/repl/replication_recovery_test.cpp b/src/mongo/db/repl/replication_recovery_test.cpp
index 25786d9c151..d07d9d977ac 100644
--- a/src/mongo/db/repl/replication_recovery_test.cpp
+++ b/src/mongo/db/repl/replication_recovery_test.cpp
@@ -26,8 +26,6 @@
  *    it in the license file.
  */
 
-#include "mongo/db/repl/replication_recovery.h"
-
 #include "mongo/platform/basic.h"
 
 #include "mongo/db/client.h"
@@ -38,9 +36,10 @@
 #include "mongo/db/repl/oplog_interface_local.h"
 #include "mongo/db/repl/replication_consistency_markers_mock.h"
 #include "mongo/db/repl/replication_coordinator_mock.h"
+#include "mongo/db/repl/replication_recovery.h"
 #include "mongo/db/repl/storage_interface_impl.h"
 #include "mongo/db/service_context_d_test_fixture.h"
-#include "mongo/db/session_catalog.h"
+#include "mongo/db/session_catalog_mongod.h"
 #include "mongo/db/session_txn_record_gen.h"
 #include "mongo/stdx/memory.h"
 #include "mongo/unittest/death_test.h"
@@ -147,7 +146,7 @@ private:
         ASSERT_OK(_storageInterface->createCollection(
             getOperationContext(), testNs, generateOptionsWithUuid()));
 
-        SessionCatalog::get(_opCtx->getServiceContext())->onStepUp(_opCtx.get());
+        MongoDSessionCatalog::onStepUp(_opCtx.get());
     }
 
     void tearDown() override {
diff --git a/src/mongo/db/repl/rs_rollback.cpp b/src/mongo/db/repl/rs_rollback.cpp
index 19eeda570b0..7c1e069fb5f 100644
--- a/src/mongo/db/repl/rs_rollback.cpp
+++ b/src/mongo/db/repl/rs_rollback.cpp
@@ -38,7 +38,6 @@
 #include "mongo/bson/bsonelement_comparator.h"
 #include "mongo/bson/util/bson_extract.h"
 #include "mongo/db/auth/authorization_manager.h"
-#include "mongo/db/auth/authorization_manager_global.h"
 #include "mongo/db/catalog/collection_catalog_entry.h"
 #include "mongo/db/catalog/database_holder.h"
 #include "mongo/db/catalog/document_validation.h"
@@ -70,7 +69,8 @@
 #include "mongo/db/repl/rollback_source.h"
 #include "mongo/db/repl/rslog.h"
 #include "mongo/db/s/shard_identity_rollback_notifier.h"
-#include "mongo/db/session_catalog.h"
+#include "mongo/db/session_catalog_mongod.h"
+#include "mongo/db/transaction_participant.h"
 #include "mongo/util/exit.h"
 #include "mongo/util/fail_point_service.h"
 #include "mongo/util/log.h"
@@ -892,7 +892,7 @@ Status _syncRollback(OperationContext* opCtx,
 
     // Find the UUID of the transactions collection. An OperationContext is required because the
     // UUID is not known at compile time, so the SessionCatalog needs to load the collection.
-    how.transactionTableUUID = SessionCatalog::getTransactionTableUUID(opCtx);
+    how.transactionTableUUID = MongoDSessionCatalog::getTransactionTableUUID(opCtx);
 
     log() << "Finding the Common Point";
     try {
@@ -1425,7 +1425,7 @@ void rollback_internal::syncFixUp(OperationContext* opCtx,
         oplogCollection->cappedTruncateAfter(opCtx, fixUpInfo.commonPointOurDiskloc, false);
     }
 
-    Status status = getGlobalAuthorizationManager()->initialize(opCtx);
+    Status status = AuthorizationManager::get(opCtx->getServiceContext())->initialize(opCtx);
     if (!status.isOK()) {
         severe() << "Failed to reinitialize auth data after rollback: " << redact(status);
         fassertFailedNoTrace(40496);
diff --git a/src/mongo/db/repl/sync_tail_test.cpp b/src/mongo/db/repl/sync_tail_test.cpp
index d51babb0075..095fa7b6e79 100644
--- a/src/mongo/db/repl/sync_tail_test.cpp
+++ b/src/mongo/db/repl/sync_tail_test.cpp
@@ -60,9 +60,8 @@
 #include "mongo/db/repl/replication_process.h"
 #include "mongo/db/repl/storage_interface.h"
 #include "mongo/db/repl/sync_tail.h"
-#include "mongo/db/service_context.h"
 #include "mongo/db/service_context_d_test_fixture.h"
-#include "mongo/db/session_catalog.h"
+#include "mongo/db/session_catalog_mongod.h"
 #include "mongo/db/session_txn_record_gen.h"
 #include "mongo/stdx/mutex.h"
 #include "mongo/unittest/death_test.h"
@@ -1562,7 +1561,7 @@ public:
     void setUp() override {
         SyncTailTest::setUp();
 
-        SessionCatalog::get(_opCtx->getServiceContext())->onStepUp(_opCtx.get());
+        MongoDSessionCatalog::onStepUp(_opCtx.get());
 
         DBDirectClient client(_opCtx.get());
         BSONObj result;
diff --git a/src/mongo/db/s/session_catalog_migration_destination_test.cpp b/src/mongo/db/s/session_catalog_migration_destination_test.cpp
index 576290f1ca4..645ae280c2e 100644
--- a/src/mongo/db/s/session_catalog_migration_destination_test.cpp
+++ b/src/mongo/db/s/session_catalog_migration_destination_test.cpp
@@ -44,6 +44,7 @@
 #include "mongo/db/s/session_catalog_migration_destination.h"
 #include "mongo/db/server_options.h"
 #include "mongo/db/session_catalog.h"
+#include "mongo/db/session_catalog_mongod.h"
 #include "mongo/db/session_txn_record_gen.h"
 #include "mongo/db/transaction_history_iterator.h"
 #include "mongo/db/transaction_participant.h"
@@ -131,7 +132,7 @@ public:
                 ->setFindHostReturnValue(kDonorConnStr.getServers()[0]);
         }
 
-        SessionCatalog::get(getServiceContext())->onStepUp(operationContext());
+        MongoDSessionCatalog::onStepUp(operationContext());
         LogicalSessionCache::set(getServiceContext(), stdx::make_unique<LogicalSessionCacheNoop>());
     }
 
diff --git a/src/mongo/db/session_catalog.cpp b/src/mongo/db/session_catalog.cpp
index 5d18e890666..9f9587e1d7f 100644
--- a/src/mongo/db/session_catalog.cpp
+++ b/src/mongo/db/session_catalog.cpp
@@ -32,11 +32,7 @@
 
 #include "mongo/db/session_catalog.h"
 
-#include <boost/optional.hpp>
-
-#include "mongo/db/db_raii.h"
 #include "mongo/db/dbdirectclient.h"
-#include "mongo/db/kill_sessions_common.h"
 #include "mongo/db/namespace_string.h"
 #include "mongo/db/operation_context.h"
 #include "mongo/db/service_context.h"
@@ -77,49 +73,6 @@ SessionCatalog* SessionCatalog::get(ServiceContext* service) {
     return &sessionTransactionTable;
 }
 
-boost::optional<UUID> SessionCatalog::getTransactionTableUUID(OperationContext* opCtx) {
-    AutoGetCollection autoColl(opCtx, NamespaceString::kSessionTransactionsTableNamespace, MODE_IS);
-
-    const auto coll = autoColl.getCollection();
-    if (coll == nullptr) {
-        return boost::none;
-    }
-
-    return coll->uuid();
-}
-
-void SessionCatalog::onStepUp(OperationContext* opCtx) {
-    invalidateSessions(opCtx, boost::none);
-
-    DBDirectClient client(opCtx);
-
-    const size_t initialExtentSize = 0;
-    const bool capped = false;
-    const bool maxSize = 0;
-
-    BSONObj result;
-
-    if (client.createCollection(NamespaceString::kSessionTransactionsTableNamespace.ns(),
-                                initialExtentSize,
-                                capped,
-                                maxSize,
-                                &result)) {
-        return;
-    }
-
-    const auto status = getStatusFromCommandResult(result);
-
-    if (status == ErrorCodes::NamespaceExists) {
-        return;
-    }
-
-    uassertStatusOKWithContext(status,
-                               str::stream()
-                                   << "Failed to create the "
-                                   << NamespaceString::kSessionTransactionsTableNamespace.ns()
-                                   << " collection");
-}
-
 ScopedCheckedOutSession SessionCatalog::checkOutSession(OperationContext* opCtx) {
     invariant(!opCtx->lockState()->isLocked());
     invariant(opCtx->getLogicalSessionId());
@@ -204,17 +157,14 @@ void SessionCatalog::invalidateSessions(OperationContext* opCtx,
 
 void SessionCatalog::scanSessions(OperationContext* opCtx,
                                   const SessionKiller::Matcher& matcher,
-                                  stdx::function<void(OperationContext*, Session*)> workerFn) {
+                                  const ScanSessionsCallbackFn& workerFn) {
     stdx::lock_guard<stdx::mutex> lg(_mutex);
 
     LOG(2) << "Beginning scanSessions. Scanning " << _sessions.size() << " sessions.";
 
-    for (auto it = _sessions.begin(); it != _sessions.end(); ++it) {
-        // TODO SERVER-33850: Rename KillAllSessionsByPattern and
-        // ScopedKillAllSessionsByPatternImpersonator to not refer to session kill.
-        if (const KillAllSessionsByPattern* pattern = matcher.match(it->first)) {
-            ScopedKillAllSessionsByPatternImpersonator impersonator(opCtx, *pattern);
-            workerFn(opCtx, &(it->second->txnState));
+    for (auto& sessionEntry : _sessions) {
+        if (matcher.match(sessionEntry.first)) {
+            workerFn(opCtx, &sessionEntry.second->txnState);
         }
     }
 }
diff --git a/src/mongo/db/session_catalog.h b/src/mongo/db/session_catalog.h
index 365202ba309..330a482de5b 100644
--- a/src/mongo/db/session_catalog.h
+++ b/src/mongo/db/session_catalog.h
@@ -28,6 +28,8 @@
 
 #pragma once
 
+#include <boost/optional.hpp>
+
 #include "mongo/base/disallow_copying.h"
 #include "mongo/db/logical_session_id.h"
 #include "mongo/db/session.h"
@@ -66,32 +68,19 @@ public:
     static SessionCatalog* get(ServiceContext* service);
 
     /**
-     * Fetches the UUID of the transaction table, or an empty optional if the collection does not
-     * exist or has no UUID. Acquires a lock on the collection. Required for rollback via refetch.
-     */
-    static boost::optional<UUID> getTransactionTableUUID(OperationContext* opCtx);
-
-    /**
      * Resets the transaction table to an uninitialized state.
      * Meant only for testing.
      */
     void reset_forTest();
 
     /**
-     * Invoked when the node enters the primary state. Ensures that the transactions collection is
-     * created. Throws on severe exceptions due to which it is not safe to continue the step-up
-     * process.
-     */
-    void onStepUp(OperationContext* opCtx);
-
-    /**
      * Potentially blocking call, which uses the session information stored in the specified
-     * operation context and either creates a new session runtime state (if one doesn't exist) or
-     * "checks-out" the existing one (if it is not currently in use).
+     * operation context and either creates a brand new session object (if one doesn't exist) or
+     * "checks-out" the existing one (if it is not currently in use or marked for kill).
      *
-     * Checking out a session puts it in the 'in use' state and all subsequent calls to checkout
-     * will block until it is put back in the 'available' state when the returned object goes out of
-     * scope.
+     * Checking out a session puts it in the 'checked out' state and all subsequent calls to
+     * checkout will block until it is checked back in. This happens when the returned object goes
+     * out of scope.
      *
      * Throws exception on errors.
      */
@@ -125,9 +114,10 @@ public:
      * SessionCatalog.
      * TODO SERVER-33850: Take Matcher out of the SessionKiller namespace.
      */
+    using ScanSessionsCallbackFn = stdx::function<void(OperationContext*, Session*)>;
     void scanSessions(OperationContext* opCtx,
                       const SessionKiller::Matcher& matcher,
-                      stdx::function<void(OperationContext*, Session*)> workerFn);
+                      const ScanSessionsCallbackFn& workerFn);
 
 private:
     struct SessionRuntimeInfo {
diff --git a/src/mongo/db/session_catalog_mongod.cpp b/src/mongo/db/session_catalog_mongod.cpp
new file mode 100644
index 00000000000..b5c059393e7
--- /dev/null
+++ b/src/mongo/db/session_catalog_mongod.cpp
@@ -0,0 +1,86 @@
+/**
+ *    Copyright (C) 2018 MongoDB, Inc.
+ *
+ *    This program is free software: you can redistribute it and/or  modify
+ *    it under the terms of the GNU Affero General Public License, version 3,
+ *    as published by the Free Software Foundation.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU Affero General Public License for more details.
+ *
+ *    You should have received a copy of the GNU Affero General Public License
+ *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the GNU Affero General Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+
+#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kWrite
+
+#include "mongo/platform/basic.h"
+
+#include "mongo/db/session_catalog_mongod.h"
+
+#include "mongo/db/catalog_raii.h"
+#include "mongo/db/client.h"
+#include "mongo/db/dbdirectclient.h"
+#include "mongo/db/namespace_string.h"
+#include "mongo/rpc/get_status_from_command_result.h"
+
+namespace mongo {
+
+void MongoDSessionCatalog::onStepUp(OperationContext* opCtx) {
+    SessionCatalog::get(opCtx)->invalidateSessions(opCtx, boost::none);
+
+    const size_t initialExtentSize = 0;
+    const bool capped = false;
+    const bool maxSize = 0;
+
+    BSONObj result;
+
+    DBDirectClient client(opCtx);
+
+    if (client.createCollection(NamespaceString::kSessionTransactionsTableNamespace.ns(),
+                                initialExtentSize,
+                                capped,
+                                maxSize,
+                                &result)) {
+        return;
+    }
+
+    const auto status = getStatusFromCommandResult(result);
+
+    if (status == ErrorCodes::NamespaceExists) {
+        return;
+    }
+
+    uassertStatusOKWithContext(status,
+                               str::stream()
+                                   << "Failed to create the "
+                                   << NamespaceString::kSessionTransactionsTableNamespace.ns()
+                                   << " collection");
+}
+
+boost::optional<UUID> MongoDSessionCatalog::getTransactionTableUUID(OperationContext* opCtx) {
+    AutoGetCollection autoColl(opCtx, NamespaceString::kSessionTransactionsTableNamespace, MODE_IS);
+
+    const auto coll = autoColl.getCollection();
+    if (!coll) {
+        return boost::none;
+    }
+
+    return coll->uuid();
+}
+
+}  // namespace mongo
diff --git a/src/mongo/db/session_catalog_mongod.h b/src/mongo/db/session_catalog_mongod.h
new file mode 100644
index 00000000000..78e745f1633
--- /dev/null
+++ b/src/mongo/db/session_catalog_mongod.h
@@ -0,0 +1,53 @@
+/**
+ *    Copyright (C) 2018 MongoDB, Inc.
+ *
+ *    This program is free software: you can redistribute it and/or  modify
+ *    it under the terms of the GNU Affero General Public License, version 3,
+ *    as published by the Free Software Foundation.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU Affero General Public License for more details.
+ *
+ *    You should have received a copy of the GNU Affero General Public License
+ *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the GNU Affero General Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+
+#pragma once
+
+#include "mongo/db/session_catalog.h"
+
+namespace mongo {
+
+class MongoDSessionCatalog {
+public:
+    /**
+     * Invoked when the node enters the primary state. Ensures that the transactions collection is
+     * created. Throws on severe exceptions due to which it is not safe to continue the step-up
+     * process.
+     */
+    static void onStepUp(OperationContext* opCtx);
+
+    /**
+     * Fetches the UUID of the transaction table, or an empty optional if the collection does not
+     * exist or has no UUID. Acquires a lock on the collection.
+     *
+     * Required for rollback via refetch.
+     */
+    static boost::optional<UUID> getTransactionTableUUID(OperationContext* opCtx);
+};
+
+}  // namespace mongo
diff --git a/src/mongo/db/session_catalog_test.cpp b/src/mongo/db/session_catalog_test.cpp
index 3efb8a0dcb3..02560433abd 100644
--- a/src/mongo/db/session_catalog_test.cpp
+++ b/src/mongo/db/session_catalog_test.cpp
@@ -28,12 +28,7 @@
 
 #include "mongo/platform/basic.h"
 
-#include "mongo/db/client.h"
-#include "mongo/db/concurrency/d_concurrency.h"
-#include "mongo/db/operation_context.h"
 #include "mongo/db/repl/mock_repl_coord_server_fixture.h"
-#include "mongo/db/repl/read_concern_args.h"
-#include "mongo/db/service_context.h"
 #include "mongo/db/session_catalog.h"
 #include "mongo/stdx/future.h"
 #include "mongo/stdx/memory.h"
@@ -49,13 +44,11 @@ protected:
     void setUp() final {
         MockReplCoordServerFixture::setUp();
 
-        auto service = opCtx()->getServiceContext();
-        SessionCatalog::get(service)->reset_forTest();
-        SessionCatalog::get(service)->onStepUp(opCtx());
+        catalog()->reset_forTest();
     }
 
     SessionCatalog* catalog() {
-        return SessionCatalog::get(opCtx()->getServiceContext());
+        return SessionCatalog::get(getServiceContext());
     }
 };
 
@@ -63,8 +56,8 @@ protected:
 class DirectClientSetter {
 public:
     explicit DirectClientSetter(OperationContext* opCtx)
-        : _opCtx(opCtx), _wasInDirectClient(opCtx->getClient()->isInDirectClient()) {
-        opCtx->getClient()->setInDirectClient(true);
+        : _opCtx(opCtx), _wasInDirectClient(_opCtx->getClient()->isInDirectClient()) {
+        _opCtx->getClient()->setInDirectClient(true);
     }
 
     ~DirectClientSetter() {
diff --git a/src/mongo/db/transaction_participant.cpp b/src/mongo/db/transaction_participant.cpp
index 6d870f6802f..1a658477cb9 100644
--- a/src/mongo/db/transaction_participant.cpp
+++ b/src/mongo/db/transaction_participant.cpp
@@ -36,13 +36,13 @@
 #include "mongo/db/transaction_participant.h"
 
 #include "mongo/db/catalog/index_catalog.h"
+#include "mongo/db/catalog_raii.h"
 #include "mongo/db/commands/test_commands_enabled.h"
 #include "mongo/db/concurrency/d_concurrency.h"
 #include "mongo/db/concurrency/lock_state.h"
 #include "mongo/db/concurrency/locker.h"
 #include "mongo/db/concurrency/write_conflict_exception.h"
 #include "mongo/db/curop_failpoint_helpers.h"
-#include "mongo/db/db_raii.h"
 #include "mongo/db/dbdirectclient.h"
 #include "mongo/db/index/index_access_method.h"
 #include "mongo/db/op_observer.h"
diff --git a/src/mongo/db/transaction_participant_retryable_writes_test.cpp b/src/mongo/db/transaction_participant_retryable_writes_test.cpp
index 0836660bba1..49803aa557b 100644
--- a/src/mongo/db/transaction_participant_retryable_writes_test.cpp
+++ b/src/mongo/db/transaction_participant_retryable_writes_test.cpp
@@ -41,8 +41,7 @@
 #include "mongo/db/server_options.h"
 #include "mongo/db/server_transactions_metrics.h"
 #include "mongo/db/service_context.h"
-#include "mongo/db/session_catalog.h"
-#include "mongo/db/stats/fill_locker_info.h"
+#include "mongo/db/session_catalog_mongod.h"
 #include "mongo/db/transaction_participant.h"
 #include "mongo/stdx/future.h"
 #include "mongo/stdx/memory.h"
@@ -127,10 +126,9 @@ protected:
     void setUp() final {
         MockReplCoordServerFixture::setUp();
 
-        auto service = opCtx()->getServiceContext();
-        SessionCatalog::get(service)->reset_forTest();
-        SessionCatalog::get(service)->onStepUp(opCtx());
+        MongoDSessionCatalog::onStepUp(opCtx());
 
+        const auto service = opCtx()->getServiceContext();
         OpObserverRegistry* opObserverRegistry =
             dynamic_cast<OpObserverRegistry*>(service->getOpObserver());
         auto mockObserver = stdx::make_unique<OpObserverMock>();
@@ -139,8 +137,11 @@ protected:
     }
 
     void tearDown() final {
-        MockReplCoordServerFixture::tearDown();
         _opObserver = nullptr;
+
+        SessionCatalog::get(opCtx()->getServiceContext())->reset_forTest();
+
+        MockReplCoordServerFixture::tearDown();
     }
 
     SessionCatalog* catalog() {
diff --git a/src/mongo/db/transaction_participant_test.cpp b/src/mongo/db/transaction_participant_test.cpp
index 20282f83b25..3753ce81cad 100644
--- a/src/mongo/db/transaction_participant_test.cpp
+++ b/src/mongo/db/transaction_participant_test.cpp
@@ -41,7 +41,7 @@
 #include "mongo/db/repl/optime.h"
 #include "mongo/db/server_transactions_metrics.h"
 #include "mongo/db/service_context.h"
-#include "mongo/db/session_catalog.h"
+#include "mongo/db/session_catalog_mongod.h"
 #include "mongo/db/stats/fill_locker_info.h"
 #include "mongo/db/transaction_participant.h"
 #include "mongo/stdx/future.h"
@@ -176,7 +176,8 @@ protected:
         MockReplCoordServerFixture::setUp();
 
         auto service = opCtx()->getServiceContext();
-        SessionCatalog::get(service)->onStepUp(opCtx());
+
+        MongoDSessionCatalog::onStepUp(opCtx());
 
         OpObserverRegistry* opObserverRegistry =
             dynamic_cast<OpObserverRegistry*>(service->getOpObserver());
diff --git a/src/mongo/dbtests/storage_timestamp_tests.cpp b/src/mongo/dbtests/storage_timestamp_tests.cpp
index d5e7cc6ae06..43c766add16 100644
--- a/src/mongo/dbtests/storage_timestamp_tests.cpp
+++ b/src/mongo/dbtests/storage_timestamp_tests.cpp
@@ -72,6 +72,7 @@
 #include "mongo/db/s/op_observer_sharding_impl.h"
 #include "mongo/db/service_context.h"
 #include "mongo/db/session.h"
+#include "mongo/db/session_catalog_mongod.h"
 #include "mongo/db/storage/kv/kv_storage_engine.h"
 #include "mongo/db/transaction_participant.h"
 #include "mongo/dbtests/dbtests.h"
@@ -2477,7 +2478,7 @@ public:
         auto service = _opCtx->getServiceContext();
         auto sessionCatalog = SessionCatalog::get(service);
         sessionCatalog->reset_forTest();
-        sessionCatalog->onStepUp(_opCtx);
+        MongoDSessionCatalog::onStepUp(_opCtx);
 
         reset(nss);
         UUID ui = UUID::gen();