SERVER-37665 Get rid of the 'checkOutSession' parameter of OperationContextSession

This simplifies the behaviour of the class and moves all the check-out
decision taking to happen in the only consumer - the endpoint.

Also renames OperationContextSessionMongoD to MongoDOperationContextSession
in order to be in sync with the naming nomenclature of SessionCatalog and
MongoDSessionCatalog.

17 files changed, 127 insertions, 234 deletions

diff --git a/src/mongo/db/SConscript b/src/mongo/db/SConscript
index c3c544a7cce..909faaaab47 100644
--- a/src/mongo/db/SConscript
+++ b/src/mongo/db/SConscript
@@ -680,7 +680,6 @@ env.Library(
     target='catalog_raii',
     source=[
         'catalog_raii.cpp',
-        'operation_context_session_mongod.cpp',
         'retryable_writes_stats.cpp',
         'server_transactions_metrics.cpp',
         'session_catalog_mongod.cpp',
diff --git a/src/mongo/db/op_observer_impl_test.cpp b/src/mongo/db/op_observer_impl_test.cpp
index 0c2501cd6f0..6bfd5a8ec48 100644
--- a/src/mongo/db/op_observer_impl_test.cpp
+++ b/src/mongo/db/op_observer_impl_test.cpp
@@ -40,7 +40,6 @@
 #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"
@@ -540,7 +539,8 @@ public:
         _times.emplace(opCtx());
         opCtx()->setLogicalSessionId(session()->getSessionId());
         opCtx()->setTxnNumber(txnNum());
-        _sessionCheckout = std::make_unique<OperationContextSessionMongod>(opCtx(), true);
+
+        _sessionCheckout = std::make_unique<MongoDOperationContextSession>(opCtx());
         auto txnParticipant = TransactionParticipant::get(opCtx());
         txnParticipant->beginOrContinue(*opCtx()->getTxnNumber(), false, true);
     }
@@ -627,7 +627,7 @@ private:
     boost::optional<ScopedSession> _session;
     ServiceContext::UniqueOperationContext _opCtx;
     boost::optional<ExposeOpObserverTimes::ReservedTimes> _times;
-    std::unique_ptr<OperationContextSessionMongod> _sessionCheckout;
+    std::unique_ptr<MongoDOperationContextSession> _sessionCheckout;
     TxnNumber _txnNum = 0;
 };
 
diff --git a/src/mongo/db/operation_context_session_mongod.cpp b/src/mongo/db/operation_context_session_mongod.cpp
deleted file mode 100644
index 6622a5f4e0d..00000000000
--- a/src/mongo/db/operation_context_session_mongod.cpp
+++ /dev/null
@@ -1,58 +0,0 @@
-
-/**
- *    Copyright (C) 2018-present MongoDB, Inc.
- *
- *    This program is free software: you can redistribute it and/or modify
- *    it under the terms of the Server Side Public License, version 1,
- *    as published by MongoDB, Inc.
- *
- *    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
- *    Server Side Public License for more details.
- *
- *    You should have received a copy of the Server Side Public License
- *    along with this program. If not, see
- *    <http://www.mongodb.com/licensing/server-side-public-license>.
- *
- *    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 Server Side 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.
- */
-
-#include "mongo/platform/basic.h"
-
-#include "mongo/db/operation_context_session_mongod.h"
-
-#include "mongo/db/transaction_participant.h"
-
-namespace mongo {
-
-OperationContextSessionMongod::OperationContextSessionMongod(OperationContext* opCtx,
-                                                             bool shouldCheckOutSession)
-    : _operationContextSession(opCtx, shouldCheckOutSession) {
-    if (shouldCheckOutSession && !opCtx->getClient()->isInDirectClient()) {
-        const auto txnParticipant = TransactionParticipant::get(opCtx);
-        txnParticipant->refreshFromStorageIfNeeded(opCtx);
-    }
-}
-
-OperationContextSessionMongodWithoutRefresh::OperationContextSessionMongodWithoutRefresh(
-    OperationContext* opCtx)
-    : _operationContextSession(opCtx, true /* checkout */) {
-    invariant(!opCtx->getClient()->isInDirectClient());
-    const auto clientTxnNumber = *opCtx->getTxnNumber();
-
-    const auto txnParticipant = TransactionParticipant::get(opCtx);
-    txnParticipant->beginOrContinueTransactionUnconditionally(clientTxnNumber);
-}
-
-}  // namespace mongo
diff --git a/src/mongo/db/operation_context_session_mongod.h b/src/mongo/db/operation_context_session_mongod.h
deleted file mode 100644
index bdbea720dbf..00000000000
--- a/src/mongo/db/operation_context_session_mongod.h
+++ /dev/null
@@ -1,69 +0,0 @@
-
-/**
- *    Copyright (C) 2018-present MongoDB, Inc.
- *
- *    This program is free software: you can redistribute it and/or modify
- *    it under the terms of the Server Side Public License, version 1,
- *    as published by MongoDB, Inc.
- *
- *    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
- *    Server Side Public License for more details.
- *
- *    You should have received a copy of the Server Side Public License
- *    along with this program. If not, see
- *    <http://www.mongodb.com/licensing/server-side-public-license>.
- *
- *    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 Server Side 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 <boost/optional.hpp>
-
-#include "mongo/db/session_catalog.h"
-
-namespace mongo {
-
-class OperationContext;
-
-/**
- * Scoped object, which checks out the session specified in the passed operation context and stores
- * it for later access by the command. The session is installed at construction time and is removed
- * at destruction.
- */
-class OperationContextSessionMongod {
-public:
-    OperationContextSessionMongod(OperationContext* opCtx, bool shouldCheckOutSession);
-
-private:
-    OperationContextSession _operationContextSession;
-};
-
-/**
- * Similar to OperationContextSessionMongod, but marks the TransactionParticipant as valid without
- * refreshing from disk and starts a new transaction unconditionally.
- *
- * NOTE: Only used by the replication oplog application logic on secondaries in order to replay
- * prepared transactions.
- */
-class OperationContextSessionMongodWithoutRefresh {
-public:
-    OperationContextSessionMongodWithoutRefresh(OperationContext* opCtx);
-
-private:
-    OperationContextSession _operationContextSession;
-};
-
-}  // namespace mongo
diff --git a/src/mongo/db/repl/apply_ops.cpp b/src/mongo/db/repl/apply_ops.cpp
index ea7e62763a0..9edb6be9bc8 100644
--- a/src/mongo/db/repl/apply_ops.cpp
+++ b/src/mongo/db/repl/apply_ops.cpp
@@ -49,10 +49,10 @@
 #include "mongo/db/matcher/matcher.h"
 #include "mongo/db/op_observer.h"
 #include "mongo/db/operation_context.h"
-#include "mongo/db/operation_context_session_mongod.h"
 #include "mongo/db/query/collation/collation_spec.h"
 #include "mongo/db/repl/replication_coordinator.h"
 #include "mongo/db/service_context.h"
+#include "mongo/db/session_catalog_mongod.h"
 #include "mongo/db/transaction_participant.h"
 #include "mongo/rpc/get_status_from_command_result.h"
 #include "mongo/util/fail_point_service.h"
@@ -313,7 +313,7 @@ Status _applyPrepareTransaction(OperationContext* opCtx,
     // The write on transaction table may be applied concurrently, so refreshing state
     // from disk may read that write, causing starting a new transaction on an existing
     // txnNumber. Thus, we start a new transaction without refreshing state from disk.
-    OperationContextSessionMongodWithoutRefresh sessionCheckout(opCtx);
+    MongoDOperationContextSessionWithoutRefresh sessionCheckout(opCtx);
 
     auto transaction = TransactionParticipant::get(opCtx);
     transaction->unstashTransactionResources(opCtx, "prepareTransaction");
diff --git a/src/mongo/db/repl/do_txn_test.cpp b/src/mongo/db/repl/do_txn_test.cpp
index 1820b17e78d..66d3017b415 100644
--- a/src/mongo/db/repl/do_txn_test.cpp
+++ b/src/mongo/db/repl/do_txn_test.cpp
@@ -35,7 +35,6 @@
 #include "mongo/db/client.h"
 #include "mongo/db/op_observer_noop.h"
 #include "mongo/db/op_observer_registry.h"
-#include "mongo/db/operation_context_session_mongod.h"
 #include "mongo/db/repl/do_txn.h"
 #include "mongo/db/repl/oplog_interface_local.h"
 #include "mongo/db/repl/repl_client_info.h"
@@ -117,7 +116,7 @@ protected:
     OpObserverMock* _opObserver = nullptr;
     std::unique_ptr<StorageInterface> _storage;
     ServiceContext::UniqueOperationContext _opCtx;
-    boost::optional<OperationContextSessionMongod> _ocs;
+    boost::optional<MongoDOperationContextSession> _ocs;
 };
 
 void DoTxnTest::setUp() {
@@ -156,7 +155,7 @@ void DoTxnTest::setUp() {
     // Set up the transaction and session.
     _opCtx->setLogicalSessionId(makeLogicalSessionIdForTest());
     _opCtx->setTxnNumber(0);  // TxnNumber can always be 0 because we have a new session.
-    _ocs.emplace(_opCtx.get(), true /* checkOutSession */);
+    _ocs.emplace(_opCtx.get());
 
     auto txnParticipant = TransactionParticipant::get(opCtx());
     txnParticipant->beginOrContinue(*opCtx()->getTxnNumber(), false, true);
diff --git a/src/mongo/db/repl/transaction_oplog_application.cpp b/src/mongo/db/repl/transaction_oplog_application.cpp
index 00460ed68f2..52f99c6fdbf 100644
--- a/src/mongo/db/repl/transaction_oplog_application.cpp
+++ b/src/mongo/db/repl/transaction_oplog_application.cpp
@@ -28,13 +28,13 @@
  *    it in the license file.
  */
 
-#include "mongo/db/repl/transaction_oplog_application.h"
-
 #include "mongo/platform/basic.h"
 
+#include "mongo/db/repl/transaction_oplog_application.h"
+
 #include "mongo/db/commands/txn_cmds_gen.h"
-#include "mongo/db/operation_context_session_mongod.h"
 #include "mongo/db/repl/apply_ops.h"
+#include "mongo/db/session_catalog_mongod.h"
 #include "mongo/db/transaction_history_iterator.h"
 #include "mongo/db/transaction_participant.h"
 
@@ -89,7 +89,7 @@ Status applyCommitTransaction(OperationContext* opCtx,
     // The write on transaction table may be applied concurrently, so refreshing state
     // from disk may read that write, causing starting a new transaction on an existing
     // txnNumber. Thus, we start a new transaction without refreshing state from disk.
-    OperationContextSessionMongodWithoutRefresh sessionCheckout(opCtx);
+    MongoDOperationContextSessionWithoutRefresh sessionCheckout(opCtx);
 
     auto transaction = TransactionParticipant::get(opCtx);
     invariant(transaction);
@@ -123,7 +123,7 @@ Status applyAbortTransaction(OperationContext* opCtx,
     // The write on transaction table may be applied concurrently, so refreshing state
     // from disk may read that write, causing starting a new transaction on an existing
     // txnNumber. Thus, we start a new transaction without refreshing state from disk.
-    OperationContextSessionMongodWithoutRefresh sessionCheckout(opCtx);
+    MongoDOperationContextSessionWithoutRefresh sessionCheckout(opCtx);
 
     auto transaction = TransactionParticipant::get(opCtx);
     transaction->unstashTransactionResources(opCtx, "abortTransaction");
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 f929156353a..95e806a0afd 100644
--- a/src/mongo/db/s/session_catalog_migration_destination_test.cpp
+++ b/src/mongo/db/s/session_catalog_migration_destination_test.cpp
@@ -37,14 +37,12 @@
 #include "mongo/db/initialize_operation_session_info.h"
 #include "mongo/db/logical_session_cache_noop.h"
 #include "mongo/db/logical_session_id.h"
-#include "mongo/db/operation_context_session_mongod.h"
 #include "mongo/db/ops/write_ops_exec.h"
 #include "mongo/db/ops/write_ops_gen.h"
 #include "mongo/db/repl/oplog_entry.h"
 #include "mongo/db/s/migration_session_id.h"
 #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"
@@ -250,7 +248,7 @@ public:
             // requests with txnNumbers aren't allowed. To get around this, we have to manually set
             // up the session state and perform the insert.
             initializeOperationSessionInfo(innerOpCtx.get(), insertBuilder.obj(), true, true, true);
-            OperationContextSessionMongod sessionTxnState(innerOpCtx.get(), true);
+            MongoDOperationContextSession sessionTxnState(innerOpCtx.get());
             auto txnParticipant = TransactionParticipant::get(innerOpCtx.get());
             txnParticipant->beginOrContinue(*sessionInfo.getTxnNumber(), boost::none, boost::none);
 
diff --git a/src/mongo/db/s/txn_two_phase_commit_cmds.cpp b/src/mongo/db/s/txn_two_phase_commit_cmds.cpp
index 7edb6c2ee4a..270d3a31cf8 100644
--- a/src/mongo/db/s/txn_two_phase_commit_cmds.cpp
+++ b/src/mongo/db/s/txn_two_phase_commit_cmds.cpp
@@ -35,9 +35,9 @@
 #include "mongo/client/remote_command_targeter.h"
 #include "mongo/db/commands.h"
 #include "mongo/db/commands/txn_two_phase_commit_cmds_gen.h"
-#include "mongo/db/operation_context_session_mongod.h"
 #include "mongo/db/repl/repl_client_info.h"
 #include "mongo/db/s/sharding_state.h"
+#include "mongo/db/session_catalog_mongod.h"
 #include "mongo/db/transaction_coordinator_service.h"
 #include "mongo/db/transaction_participant.h"
 #include "mongo/executor/task_executor.h"
diff --git a/src/mongo/db/service_entry_point_common.cpp b/src/mongo/db/service_entry_point_common.cpp
index 292bbf6db7b..c695741d003 100644
--- a/src/mongo/db/service_entry_point_common.cpp
+++ b/src/mongo/db/service_entry_point_common.cpp
@@ -57,7 +57,6 @@
 #include "mongo/db/logical_session_id.h"
 #include "mongo/db/logical_session_id_helpers.h"
 #include "mongo/db/logical_time_validator.h"
-#include "mongo/db/operation_context_session_mongod.h"
 #include "mongo/db/ops/write_ops.h"
 #include "mongo/db/ops/write_ops_exec.h"
 #include "mongo/db/query/find.h"
@@ -70,6 +69,7 @@
 #include "mongo/db/s/sharded_connection_info.h"
 #include "mongo/db/s/sharding_state.h"
 #include "mongo/db/service_entry_point_common.h"
+#include "mongo/db/session_catalog_mongod.h"
 #include "mongo/db/snapshot_window_util.h"
 #include "mongo/db/stats/counters.h"
 #include "mongo/db/stats/top.h"
@@ -576,9 +576,11 @@ void execCommandDatabase(OperationContext* opCtx,
         // handles the appropriate state management for both multi-statement transactions and
         // retryable writes. Currently, only requests with a transaction number will check out the
         // session.
-        const bool shouldCheckOutSession = static_cast<bool>(sessionOptions.getTxnNumber()) &&
-            !shouldCommandSkipSessionCheckout(command->getName());
-        OperationContextSessionMongod sessionTxnState(opCtx, shouldCheckOutSession);
+        boost::optional<MongoDOperationContextSession> sessionTxnState;
+        const bool shouldCheckOutSession =
+            sessionOptions.getTxnNumber() && !shouldCommandSkipSessionCheckout(command->getName());
+        if (shouldCheckOutSession)
+            sessionTxnState.emplace(opCtx);
 
         std::unique_ptr<MaintenanceModeSetter> mmSetter;
 
diff --git a/src/mongo/db/session_catalog.cpp b/src/mongo/db/session_catalog.cpp
index 70049de30a4..bc6d09710a5 100644
--- a/src/mongo/db/session_catalog.cpp
+++ b/src/mongo/db/session_catalog.cpp
@@ -186,55 +186,44 @@ void SessionCatalog::_releaseSession(const LogicalSessionId& lsid,
     }
 }
 
-OperationContextSession::OperationContextSession(OperationContext* opCtx, bool checkOutSession)
-    : _opCtx(opCtx) {
-    if (!opCtx->getLogicalSessionId()) {
-        return;
-    }
-
-    if (!checkOutSession) {
-        return;
-    }
-
+OperationContextSession::OperationContextSession(OperationContext* opCtx) : _opCtx(opCtx) {
     auto& checkedOutSession = operationSessionDecoration(opCtx);
-    if (!checkedOutSession) {
-        auto sessionTransactionTable = SessionCatalog::get(opCtx);
-        auto scopedCheckedOutSession = sessionTransactionTable->checkOutSession(opCtx);
-        // We acquire a Client lock here to guard the construction of this session so that
-        // references to this session are safe to use while the lock is held.
-        stdx::lock_guard<Client> lk(*opCtx->getClient());
-        checkedOutSession.emplace(std::move(scopedCheckedOutSession));
-    } else {
-        // The only reason to be trying to check out a session when you already have a session
-        // checked out is if you're in DBDirectClient.
+    if (checkedOutSession) {
+        // The only case where a session can be checked-out more than once is due to DBDirectClient
+        // reentrancy
         invariant(opCtx->getClient()->isInDirectClient());
         return;
     }
 
-    const auto session = checkedOutSession->get();
-    invariant(opCtx->getLogicalSessionId() == session->getSessionId());
+    const auto catalog = SessionCatalog::get(opCtx);
+    auto scopedCheckedOutSession = catalog->checkOutSession(opCtx);
+
+    // We acquire a Client lock here to guard the construction of this session so that references to
+    // this session are safe to use while the lock is held
+    stdx::lock_guard<Client> lk(*opCtx->getClient());
+    checkedOutSession.emplace(std::move(scopedCheckedOutSession));
 }
 
 OperationContextSession::~OperationContextSession() {
-    // Only release the checked out session at the end of the top-level request from the client,
-    // not at the end of a nested DBDirectClient call.
+    // Only release the checked out session at the end of the top-level request from the client, not
+    // at the end of a nested DBDirectClient call
     if (_opCtx->getClient()->isInDirectClient()) {
         return;
     }
 
     auto& checkedOutSession = operationSessionDecoration(_opCtx);
-    if (checkedOutSession) {
-        // Removing the checkedOutSession from the OperationContext must be done under the Client
-        // lock, but destruction of the checkedOutSession must not be, as it takes the
-        // SessionCatalog mutex, and other code may take the Client lock while holding that mutex.
-        stdx::unique_lock<Client> lk(*_opCtx->getClient());
-        ScopedCheckedOutSession sessionToDelete(std::move(checkedOutSession.get()));
-
-        // This destroys the moved-from ScopedCheckedOutSession, and must be done within the client
-        // lock.
-        checkedOutSession = boost::none;
-        lk.unlock();
-    }
+    if (!checkedOutSession)
+        return;
+
+    // Removing the checkedOutSession from the OperationContext must be done under the Client lock,
+    // but destruction of the checkedOutSession must not be, as it takes the SessionCatalog mutex,
+    // and other code may take the Client lock while holding that mutex.
+    stdx::unique_lock<Client> lk(*_opCtx->getClient());
+    ScopedCheckedOutSession sessionToDelete(std::move(checkedOutSession.get()));
+
+    // This destroys the moved-from ScopedCheckedOutSession, and must be done within the client lock
+    checkedOutSession = boost::none;
+    lk.unlock();
 }
 
 Session* OperationContextSession::get(OperationContext* opCtx) {
diff --git a/src/mongo/db/session_catalog.h b/src/mongo/db/session_catalog.h
index 8e2a35d8b8d..020d1fa5c06 100644
--- a/src/mongo/db/session_catalog.h
+++ b/src/mongo/db/session_catalog.h
@@ -250,7 +250,7 @@ class OperationContextSession {
     MONGO_DISALLOW_COPYING(OperationContextSession);
 
 public:
-    OperationContextSession(OperationContext* opCtx, bool checkOutSession);
+    OperationContextSession(OperationContext* opCtx);
     ~OperationContextSession();
 
     /**
diff --git a/src/mongo/db/session_catalog_mongod.cpp b/src/mongo/db/session_catalog_mongod.cpp
index 1c844bd78f0..5ea8173ca05 100644
--- a/src/mongo/db/session_catalog_mongod.cpp
+++ b/src/mongo/db/session_catalog_mongod.cpp
@@ -171,4 +171,23 @@ void MongoDSessionCatalog::invalidateSessions(OperationContext* opCtx,
     }));
 }
 
+
+MongoDOperationContextSession::MongoDOperationContextSession(OperationContext* opCtx)
+    : _operationContextSession(opCtx) {
+    if (!opCtx->getClient()->isInDirectClient()) {
+        const auto txnParticipant = TransactionParticipant::get(opCtx);
+        txnParticipant->refreshFromStorageIfNeeded(opCtx);
+    }
+}
+
+MongoDOperationContextSessionWithoutRefresh::MongoDOperationContextSessionWithoutRefresh(
+    OperationContext* opCtx)
+    : _operationContextSession(opCtx) {
+    invariant(!opCtx->getClient()->isInDirectClient());
+    const auto clientTxnNumber = *opCtx->getTxnNumber();
+
+    const auto txnParticipant = TransactionParticipant::get(opCtx);
+    txnParticipant->beginOrContinueTransactionUnconditionally(clientTxnNumber);
+}
+
 }  // namespace mongo
diff --git a/src/mongo/db/session_catalog_mongod.h b/src/mongo/db/session_catalog_mongod.h
index 4496c8b17f3..c71e0dce076 100644
--- a/src/mongo/db/session_catalog_mongod.h
+++ b/src/mongo/db/session_catalog_mongod.h
@@ -65,4 +65,32 @@ public:
                                    boost::optional<BSONObj> singleSessionDoc);
 };
 
+/**
+ * Scoped object, which checks out the session specified in the passed operation context and stores
+ * it for later access by the command. The session is installed at construction time and is removed
+ * at destruction.
+ */
+class MongoDOperationContextSession {
+public:
+    MongoDOperationContextSession(OperationContext* opCtx);
+
+private:
+    OperationContextSession _operationContextSession;
+};
+
+/**
+ * Similar to MongoDOperationContextSession, but marks the TransactionParticipant as valid without
+ * refreshing from disk and starts a new transaction unconditionally.
+ *
+ * NOTE: Only used by the replication oplog application logic on secondaries in order to replay
+ * prepared transactions.
+ */
+class MongoDOperationContextSessionWithoutRefresh {
+public:
+    MongoDOperationContextSessionWithoutRefresh(OperationContext* opCtx);
+
+private:
+    OperationContextSession _operationContextSession;
+};
+
 }  // namespace mongo
diff --git a/src/mongo/db/session_catalog_test.cpp b/src/mongo/db/session_catalog_test.cpp
index 1f8312b6e69..09bf4c7e878 100644
--- a/src/mongo/db/session_catalog_test.cpp
+++ b/src/mongo/db/session_catalog_test.cpp
@@ -92,21 +92,12 @@ TEST_F(SessionCatalogTestWithDefaultOpCtx, OperationContextCheckedOutSession) {
     const TxnNumber txnNum = 20;
     _opCtx->setTxnNumber(txnNum);
 
-    OperationContextSession ocs(_opCtx, true);
+    OperationContextSession ocs(_opCtx);
     auto session = OperationContextSession::get(_opCtx);
     ASSERT(session);
     ASSERT_EQ(*_opCtx->getLogicalSessionId(), session->getSessionId());
 }
 
-TEST_F(SessionCatalogTestWithDefaultOpCtx, OperationContextNonCheckedOutSession) {
-    _opCtx->setLogicalSessionId(makeLogicalSessionIdForTest());
-
-    OperationContextSession ocs(_opCtx, false);
-    auto session = OperationContextSession::get(_opCtx);
-
-    ASSERT(!session);
-}
-
 TEST_F(SessionCatalogTestWithDefaultOpCtx, GetOrCreateNonExistentSession) {
     const auto lsid = makeLogicalSessionIdForTest();
     auto scopedSession = catalog()->getOrCreateSession(_opCtx, lsid);
@@ -120,7 +111,7 @@ TEST_F(SessionCatalogTestWithDefaultOpCtx, GetOrCreateSessionAfterCheckOutSessio
     _opCtx->setLogicalSessionId(lsid);
 
     boost::optional<OperationContextSession> ocs;
-    ocs.emplace(_opCtx, true);
+    ocs.emplace(_opCtx);
 
     stdx::async(stdx::launch::async, [&] {
         ThreadClient tc(getGlobalServiceContext());
@@ -149,11 +140,11 @@ TEST_F(SessionCatalogTestWithDefaultOpCtx, NestedOperationContextSession) {
     _opCtx->setLogicalSessionId(makeLogicalSessionIdForTest());
 
     {
-        OperationContextSession outerScopedSession(_opCtx, true);
+        OperationContextSession outerScopedSession(_opCtx);
 
         {
             DirectClientSetter inDirectClient(_opCtx);
-            OperationContextSession innerScopedSession(_opCtx, true);
+            OperationContextSession innerScopedSession(_opCtx);
 
             auto session = OperationContextSession::get(_opCtx);
             ASSERT(session);
@@ -214,7 +205,7 @@ TEST_F(SessionCatalogTest, KillSessionWhenSessionIsNotCheckedOut) {
     {
         auto opCtx = makeOperationContext();
         opCtx->setLogicalSessionId(lsid);
-        OperationContextSession unusedOperationContextSession(opCtx.get(), true);
+        OperationContextSession unusedOperationContextSession(opCtx.get());
     }
 
     auto killToken = catalog()->killSession(lsid);
@@ -224,9 +215,8 @@ TEST_F(SessionCatalogTest, KillSessionWhenSessionIsNotCheckedOut) {
         auto opCtx = makeOperationContext();
         opCtx->setLogicalSessionId(lsid);
         opCtx->setDeadlineAfterNowBy(Milliseconds(10), ErrorCodes::MaxTimeMSExpired);
-        ASSERT_THROWS_CODE(OperationContextSession(opCtx.get(), true),
-                           AssertionException,
-                           ErrorCodes::MaxTimeMSExpired);
+        ASSERT_THROWS_CODE(
+            OperationContextSession(opCtx.get()), AssertionException, ErrorCodes::MaxTimeMSExpired);
     }
 
     // Schedule a separate "regular operation" thread, which will block on checking-out the session,
@@ -236,7 +226,7 @@ TEST_F(SessionCatalogTest, KillSessionWhenSessionIsNotCheckedOut) {
         auto sideOpCtx = Client::getCurrent()->makeOperationContext();
         sideOpCtx->setLogicalSessionId(lsid);
 
-        OperationContextSession unusedOperationContextSession(sideOpCtx.get(), true);
+        OperationContextSession unusedOperationContextSession(sideOpCtx.get());
     });
     ASSERT(stdx::future_status::ready != future.wait_for(Milliseconds(10).toSystemDuration()));
 
@@ -251,7 +241,7 @@ TEST_F(SessionCatalogTest, KillSessionWhenSessionIsNotCheckedOut) {
     {
         auto opCtx = makeOperationContext();
         opCtx->setLogicalSessionId(lsid);
-        OperationContextSession unusedOperationContextSession(opCtx.get(), true);
+        OperationContextSession unusedOperationContextSession(opCtx.get());
     }
 
     // Make sure the "regular operation" eventually is able to proceed and use the just killed
@@ -266,7 +256,7 @@ TEST_F(SessionCatalogTest, KillSessionWhenSessionIsCheckedOut) {
         // Create the session so there is something to kill
         auto opCtx = makeOperationContext();
         opCtx->setLogicalSessionId(lsid);
-        OperationContextSession operationContextSession(opCtx.get(), true);
+        OperationContextSession operationContextSession(opCtx.get());
 
         auto killToken = catalog()->killSession(lsid);
 
@@ -281,7 +271,7 @@ TEST_F(SessionCatalogTest, KillSessionWhenSessionIsCheckedOut) {
             sideOpCtx->setLogicalSessionId(lsid);
             sideOpCtx->setDeadlineAfterNowBy(Milliseconds(10), ErrorCodes::MaxTimeMSExpired);
 
-            OperationContextSession unusedOperationContextSession(sideOpCtx.get(), true);
+            OperationContextSession unusedOperationContextSession(sideOpCtx.get());
         });
 
         ASSERT_THROWS_CODE(future.get(), AssertionException, ErrorCodes::MaxTimeMSExpired);
@@ -294,9 +284,8 @@ TEST_F(SessionCatalogTest, KillSessionWhenSessionIsCheckedOut) {
         auto opCtx = makeOperationContext();
         opCtx->setLogicalSessionId(lsid);
         opCtx->setDeadlineAfterNowBy(Milliseconds(10), ErrorCodes::MaxTimeMSExpired);
-        ASSERT_THROWS_CODE(OperationContextSession(opCtx.get(), true),
-                           AssertionException,
-                           ErrorCodes::MaxTimeMSExpired);
+        ASSERT_THROWS_CODE(
+            OperationContextSession(opCtx.get()), AssertionException, ErrorCodes::MaxTimeMSExpired);
     }
 
     // Schedule a separate "regular operation" thread, which will block on checking-out the session,
@@ -306,7 +295,7 @@ TEST_F(SessionCatalogTest, KillSessionWhenSessionIsCheckedOut) {
         auto sideOpCtx = Client::getCurrent()->makeOperationContext();
         sideOpCtx->setLogicalSessionId(lsid);
 
-        OperationContextSession unusedOperationContextSession(sideOpCtx.get(), true);
+        OperationContextSession unusedOperationContextSession(sideOpCtx.get());
     });
     ASSERT(stdx::future_status::ready != future.wait_for(Milliseconds(10).toSystemDuration()));
 
@@ -321,7 +310,7 @@ TEST_F(SessionCatalogTest, KillSessionWhenSessionIsCheckedOut) {
     {
         auto opCtx = makeOperationContext();
         opCtx->setLogicalSessionId(lsid);
-        OperationContextSession unusedOperationContextSession(opCtx.get(), true);
+        OperationContextSession unusedOperationContextSession(opCtx.get());
     }
 
     // Make sure the "regular operation" eventually is able to proceed and use the just killed
@@ -336,7 +325,7 @@ TEST_F(SessionCatalogTest, MarkSessionAsKilledThrowsWhenCalledTwice) {
     {
         auto opCtx = makeOperationContext();
         opCtx->setLogicalSessionId(lsid);
-        OperationContextSession unusedOperationContextSession(opCtx.get(), true);
+        OperationContextSession unusedOperationContextSession(opCtx.get());
     }
 
     auto killToken = catalog()->killSession(lsid);
@@ -351,9 +340,8 @@ TEST_F(SessionCatalogTest, MarkSessionAsKilledThrowsWhenCalledTwice) {
         auto opCtx = makeOperationContext();
         opCtx->setLogicalSessionId(lsid);
         opCtx->setDeadlineAfterNowBy(Milliseconds(10), ErrorCodes::MaxTimeMSExpired);
-        ASSERT_THROWS_CODE(OperationContextSession(opCtx.get(), true),
-                           AssertionException,
-                           ErrorCodes::MaxTimeMSExpired);
+        ASSERT_THROWS_CODE(
+            OperationContextSession(opCtx.get()), AssertionException, ErrorCodes::MaxTimeMSExpired);
     }
 
     // Finish "killing" the session so the SessionCatalog destructor doesn't complain
@@ -388,7 +376,7 @@ TEST_F(SessionCatalogTestWithDefaultOpCtx, KillSessionsThroughScanSessions) {
                     auto sideOpCtx = Client::getCurrent()->makeOperationContext();
                     sideOpCtx->setLogicalSessionId(lsid);
 
-                    OperationContextSession unusedOperationContextSession(sideOpCtx.get(), true);
+                    OperationContextSession unusedOperationContextSession(sideOpCtx.get());
                     firstUseOfTheSessionReachedBarrier.countDownAndWait();
 
                     ASSERT_THROWS_CODE(sideOpCtx->sleepFor(Hours{6}),
@@ -400,7 +388,7 @@ TEST_F(SessionCatalogTestWithDefaultOpCtx, KillSessionsThroughScanSessions) {
                     auto sideOpCtx = Client::getCurrent()->makeOperationContext();
                     sideOpCtx->setLogicalSessionId(lsid);
 
-                    OperationContextSession unusedOperationContextSession(sideOpCtx.get(), true);
+                    OperationContextSession unusedOperationContextSession(sideOpCtx.get());
                 }
             }));
     }
diff --git a/src/mongo/db/transaction_participant_test.cpp b/src/mongo/db/transaction_participant_test.cpp
index d6b64bc960b..1518edff739 100644
--- a/src/mongo/db/transaction_participant_test.cpp
+++ b/src/mongo/db/transaction_participant_test.cpp
@@ -36,7 +36,6 @@
 #include "mongo/db/op_observer_noop.h"
 #include "mongo/db/op_observer_registry.h"
 #include "mongo/db/operation_context.h"
-#include "mongo/db/operation_context_session_mongod.h"
 #include "mongo/db/repl/mock_repl_coord_server_fixture.h"
 #include "mongo/db/repl/oplog.h"
 #include "mongo/db/repl/oplog_entry.h"
@@ -272,8 +271,8 @@ protected:
         runFunctionFromDifferentOpCtx(func);
     }
 
-    std::unique_ptr<OperationContextSessionMongod> checkOutSession() {
-        auto opCtxSession = std::make_unique<OperationContextSessionMongod>(opCtx(), true);
+    std::unique_ptr<MongoDOperationContextSession> checkOutSession() {
+        auto opCtxSession = std::make_unique<MongoDOperationContextSession>(opCtx());
         auto txnParticipant = TransactionParticipant::get(opCtx());
         txnParticipant->beginOrContinue(*opCtx()->getTxnNumber(), false, true);
         return opCtxSession;
@@ -318,7 +317,7 @@ TEST_F(TxnParticipantTest, TransactionThrowsLockTimeoutIfLockIsUnavailable) {
         newOpCtx.get()->setLogicalSessionId(newSessionId);
         newOpCtx.get()->setTxnNumber(newTxnNum);
 
-        OperationContextSessionMongod newOpCtxSession(newOpCtx.get(), true);
+        MongoDOperationContextSession newOpCtxSession(newOpCtx.get());
         auto newTxnParticipant = TransactionParticipant::get(newOpCtx.get());
         newTxnParticipant->beginOrContinue(newTxnNum, false, true);
         newTxnParticipant->unstashTransactionResources(newOpCtx.get(), "insert");
@@ -1077,7 +1076,7 @@ TEST_F(TxnParticipantTest, ContinuingATransactionWithNoResourcesAborts) {
     checkOutSession();
 
     // Check out the session again for a new operation.
-    OperationContextSessionMongod sessionCheckout(opCtx(), true);
+    MongoDOperationContextSession sessionCheckout(opCtx());
     auto txnParticipant = TransactionParticipant::get(opCtx());
 
     ASSERT_THROWS_CODE(
@@ -1278,7 +1277,7 @@ DEATH_TEST_F(TxnParticipantTest, AbortIsIllegalDuringCommittingPreparedTransacti
 }
 
 TEST_F(TxnParticipantTest, CannotContinueNonExistentTransaction) {
-    OperationContextSessionMongod opCtxSession(opCtx(), true);
+    MongoDOperationContextSession opCtxSession(opCtx());
     auto txnParticipant = TransactionParticipant::get(opCtx());
     ASSERT_THROWS_CODE(
         txnParticipant->beginOrContinue(*opCtx()->getTxnNumber(), false, boost::none),
@@ -1333,7 +1332,7 @@ TEST_F(TxnParticipantTest, StashInNestedSessionIsANoop) {
     {
         // Make it look like we're in a DBDirectClient running a nested operation.
         DirectClientSetter inDirectClient(opCtx());
-        OperationContextSessionMongod innerScopedSession(opCtx(), true);
+        MongoDOperationContextSession innerScopedSession(opCtx());
 
         txnParticipant->stashTransactionResources(opCtx());
 
@@ -1346,7 +1345,6 @@ TEST_F(TxnParticipantTest, StashInNestedSessionIsANoop) {
 }
 
 TEST_F(TxnParticipantTest, UnstashInNestedSessionIsANoop) {
-
     auto outerScopedSession = checkOutSession();
 
     Locker* originalLocker = opCtx()->lockState();
@@ -1366,7 +1364,7 @@ TEST_F(TxnParticipantTest, UnstashInNestedSessionIsANoop) {
     {
         // Make it look like we're in a DBDirectClient running a nested operation.
         DirectClientSetter inDirectClient(opCtx());
-        OperationContextSessionMongod innerScopedSession(opCtx(), true);
+        MongoDOperationContextSession innerScopedSession(opCtx());
 
         auto txnParticipant = TransactionParticipant::get(opCtx());
         txnParticipant->unstashTransactionResources(opCtx(), "find");
@@ -1451,7 +1449,7 @@ protected:
     }
 
     void cannotSpecifyStartTransactionOnStartedRetryableWrite() {
-        OperationContextSessionMongod opCtxSession(opCtx(), true);
+        MongoDOperationContextSession opCtxSession(opCtx());
 
         auto txnParticipant = TransactionParticipant::get(opCtx());
         txnParticipant->beginOrContinue(*opCtx()->getTxnNumber(), boost::none, boost::none);
@@ -2895,7 +2893,7 @@ TEST_F(TransactionsMetricsTest, ReportUnstashedResourcesForARetryableWrite) {
     ASSERT(opCtx()->lockState());
     ASSERT(opCtx()->recoveryUnit());
 
-    OperationContextSessionMongod opCtxSession(opCtx(), true);
+    MongoDOperationContextSession opCtxSession(opCtx());
     auto txnParticipant = TransactionParticipant::get(opCtx());
     txnParticipant->beginOrContinue(*opCtx()->getTxnNumber(), boost::none, boost::none);
     txnParticipant->unstashTransactionResources(opCtx(), "find");
@@ -3571,7 +3569,7 @@ TEST_F(TxnParticipantTest, WhenOldestTSRemovedNextOldestBecomesNewOldest) {
         newOpCtx.get()->setLogicalSessionId(newSessionId);
         newOpCtx.get()->setTxnNumber(newTxnNum);
 
-        OperationContextSessionMongod newOpCtxSession(newOpCtx.get(), true);
+        MongoDOperationContextSession newOpCtxSession(newOpCtx.get());
         auto newTxnParticipant = TransactionParticipant::get(newOpCtx.get());
         newTxnParticipant->beginOrContinue(newTxnNum, false, true);
         newTxnParticipant->unstashTransactionResources(newOpCtx.get(), "prepareTransaction");
@@ -3633,7 +3631,7 @@ TEST_F(TxnParticipantTest, ReturnNullTimestampIfNoOldestActiveTimestamp) {
         newOpCtx.get()->setLogicalSessionId(newSessionId);
         newOpCtx.get()->setTxnNumber(newTxnNum);
 
-        OperationContextSessionMongod newOpCtxSession(newOpCtx.get(), true);
+        MongoDOperationContextSession newOpCtxSession(newOpCtx.get());
         auto newTxnParticipant = TransactionParticipant::get(newOpCtx.get());
         newTxnParticipant->beginOrContinue(newTxnNum, false, true);
         newTxnParticipant->unstashTransactionResources(newOpCtx.get(), "prepareTransaction");
diff --git a/src/mongo/dbtests/storage_timestamp_tests.cpp b/src/mongo/dbtests/storage_timestamp_tests.cpp
index 468474393a1..7688df65a5c 100644
--- a/src/mongo/dbtests/storage_timestamp_tests.cpp
+++ b/src/mongo/dbtests/storage_timestamp_tests.cpp
@@ -53,7 +53,6 @@
 #include "mongo/db/logical_clock.h"
 #include "mongo/db/multi_key_path_tracker.h"
 #include "mongo/db/op_observer_registry.h"
-#include "mongo/db/operation_context_session_mongod.h"
 #include "mongo/db/repl/apply_ops.h"
 #include "mongo/db/repl/drop_pending_collection_reaper.h"
 #include "mongo/db/repl/multiapplier.h"
@@ -2498,7 +2497,7 @@ public:
         _opCtx->setLogicalSessionId(sessionId);
         _opCtx->setTxnNumber(26);
 
-        ocs = std::make_unique<OperationContextSessionMongod>(_opCtx, true);
+        ocs.emplace(_opCtx);
 
         auto txnParticipant = TransactionParticipant::get(_opCtx);
         ASSERT(txnParticipant);
@@ -2539,7 +2538,8 @@ protected:
     Timestamp presentTs;
     Timestamp beforeTxnTs;
     Timestamp commitEntryTs;
-    std::unique_ptr<OperationContextSessionMongod> ocs;
+
+    boost::optional<MongoDOperationContextSession> ocs;
 };
 
 class MultiDocumentTransaction : public MultiDocumentTransactionTest {