SERVER-34101 Revert change to free transaction resources on snapshot read killCursors

9 files changed, 51 insertions, 349 deletions

diff --git a/jstests/noPassthrough/kill_snapshot_cursor.js b/jstests/noPassthrough/kill_snapshot_cursor.js
deleted file mode 100644
index c1916a0926a..00000000000
--- a/jstests/noPassthrough/kill_snapshot_cursor.js
+++ /dev/null
@@ -1,140 +0,0 @@
-// Tests that destroying a snapshot read cursor aborts its transaction.
-// @tags: [requires_replication]
-(function() {
-    "use strict";
-
-    const dbName = "test";
-    const collName = "coll";
-
-    // The cursor timeout thread runs every 'cursorMonitorFrequencySecs' seconds, timing out cursors
-    // that have been inactive for 'cursorTimeoutMs' milliseconds.
-    const cursorTimeoutMs = 2000;
-    const cursorMonitorFrequencySecs = 1;
-
-    const options = {
-        setParameter: {
-            // We use the "cursorTimeoutMillis" server parameter to decrease how long it takes for a
-            // non-exhausted cursor to time out. We use the "clientCursorMonitorFrequencySecs"
-            // server parameter to make the ClientCursorMonitor that cleans up the timed out cursors
-            // run more often. The combination of these server parameters reduces the amount of time
-            // we need to wait within this test.
-            cursorTimeoutMillis: cursorTimeoutMs,
-            clientCursorMonitorFrequencySecs: cursorMonitorFrequencySecs,
-        }
-    };
-
-    const rst = new ReplSetTest({nodes: 1, nodeOptions: options});
-    rst.startSet();
-    rst.initiate();
-
-    const primaryDB = rst.getPrimary().getDB(dbName);
-    if (!primaryDB.serverStatus().storageEngine.supportsSnapshotReadConcern) {
-        rst.stopSet();
-        return;
-    }
-
-    const session = primaryDB.getMongo().startSession();
-    const sessionDB = session.getDatabase(dbName);
-    let txnNumber = 0;
-
-    //
-    // Test killCursors.
-    //
-
-    for (let i = 0; i < 4; i++) {
-        sessionDB.coll.insert({_id: i}, {writeConcern: {w: "majority"}});
-    }
-
-    // Create a snapshot read cursor.
-    let res = assert.commandWorked(sessionDB.runCommand({
-        find: collName,
-        batchSize: 2,
-        readConcern: {level: "snapshot"},
-        txnNumber: NumberLong(++txnNumber)
-    }));
-
-    // It should not be possible to drop the collection.
-    assert.commandFailedWithCode(sessionDB.runCommand({drop: collName, maxTimeMS: 500}),
-                                 ErrorCodes.ExceededTimeLimit);
-
-    // Kill the cursor.
-    assert.commandWorked(sessionDB.runCommand({killCursors: collName, cursors: [res.cursor.id]}));
-
-    // It should be possible to drop the collection.
-    sessionDB.coll.drop();
-
-    //
-    // Test legacy killCursors.
-    //
-
-    for (let i = 0; i < 4; i++) {
-        sessionDB.coll.insert({_id: i}, {writeConcern: {w: "majority"}});
-    }
-
-    // Create a snapshot read cursor.
-    res = assert.commandWorked(sessionDB.runCommand({
-        find: collName,
-        batchSize: 2,
-        readConcern: {level: "snapshot"},
-        txnNumber: NumberLong(++txnNumber)
-    }));
-
-    // It should not be possible to drop the collection.
-    assert.commandFailedWithCode(sessionDB.runCommand({drop: collName, maxTimeMS: 500}),
-                                 ErrorCodes.ExceededTimeLimit);
-
-    // Kill the cursor using legacy.
-    primaryDB.getMongo().forceReadMode("legacy");
-    let cursor = new DBCommandCursor(primaryDB, res);
-    cursor.close();
-    primaryDB.getMongo().forceReadMode("commands");
-
-    // It should be possible to drop the collection.
-    sessionDB.coll.drop();
-
-    //
-    // Test cursor timeout.
-    //
-
-    for (let i = 0; i < 4; i++) {
-        sessionDB.coll.insert({_id: i}, {writeConcern: {w: "majority"}});
-    }
-
-    let serverStatus = assert.commandWorked(sessionDB.serverStatus());
-    const expectedNumTimedOutCursors = serverStatus.metrics.cursor.timedOut + 1;
-
-    // Create a snapshot read cursor.
-    res = assert.commandWorked(sessionDB.runCommand({
-        find: collName,
-        batchSize: 2,
-        readConcern: {level: "snapshot"},
-        txnNumber: NumberLong(++txnNumber)
-    }));
-
-    // It should not be possible to drop the collection.
-    assert.commandFailedWithCode(sessionDB.runCommand({drop: collName, maxTimeMS: 500}),
-                                 ErrorCodes.ExceededTimeLimit);
-
-    // Wait until the idle cursor background job has killed the cursor.
-    assert.soon(
-        function() {
-            serverStatus = assert.commandWorked(sessionDB.serverStatus());
-            return +serverStatus.metrics.cursor.timedOut === expectedNumTimedOutCursors;
-        },
-        function() {
-            return "cursor failed to time out: " + tojson(serverStatus.metrics.cursor);
-        });
-    assert.eq(0, serverStatus.metrics.cursor.open.total, tojson(serverStatus));
-
-    // Verify that the cursor was killed.
-    assert.commandFailedWithCode(
-        sessionDB.runCommand(
-            {getMore: res.cursor.id, collection: collName, txnNumber: NumberLong(txnNumber)}),
-        ErrorCodes.CursorNotFound);
-
-    // It should be possible to drop the collection.
-    sessionDB.coll.drop();
-
-    session.endSession();
-    rst.stopSet();
-})();
diff --git a/src/mongo/db/commands/killcursors_cmd.cpp b/src/mongo/db/commands/killcursors_cmd.cpp
index 453c703dfa4..512ec7e0e94 100644
--- a/src/mongo/db/commands/killcursors_cmd.cpp
+++ b/src/mongo/db/commands/killcursors_cmd.cpp
@@ -36,7 +36,6 @@
 #include "mongo/db/cursor_manager.h"
 #include "mongo/db/db_raii.h"
 #include "mongo/db/query/killcursors_request.h"
-#include "mongo/db/session_catalog.h"
 #include "mongo/db/stats/top.h"
 #include "mongo/util/scopeguard.h"
 
@@ -72,28 +71,10 @@ private:
             }
         }
 
-        boost::optional<std::pair<LogicalSessionId, TxnNumber>> txnToAbort;
-
-        auto status = CursorManager::withCursorManager(
-            opCtx, id, nss, [opCtx, id, &txnToAbort](CursorManager* manager) {
-                auto status = manager->killCursor(opCtx, id, true /* shouldAudit */);
-                if (status.isOK()) {
-                    txnToAbort = status.getValue();
-                }
-                return status.getStatus();
+        return CursorManager::withCursorManager(
+            opCtx, id, nss, [opCtx, id](CursorManager* manager) {
+                return manager->killCursor(opCtx, id, true /* shouldAudit */);
             });
-
-        // If the cursor has a corresponding transaction, abort that transaction if it is a snapshot
-        // read. This must be done while we are not holding locks.
-        invariant(!opCtx->lockState()->isLocked());
-        if (txnToAbort) {
-            auto session = SessionCatalog::get(opCtx)->getSession(opCtx, txnToAbort->first);
-            if (session) {
-                (*session)->abortIfSnapshotRead(txnToAbort->second);
-            }
-        }
-
-        return status;
     }
 } killCursorsCmd;
 
diff --git a/src/mongo/db/cursor_manager.cpp b/src/mongo/db/cursor_manager.cpp
index 4ae9bafd9ed..39c82910bcb 100644
--- a/src/mongo/db/cursor_manager.cpp
+++ b/src/mongo/db/cursor_manager.cpp
@@ -50,7 +50,6 @@
 #include "mongo/db/query/plan_executor.h"
 #include "mongo/db/server_parameters.h"
 #include "mongo/db/service_context.h"
-#include "mongo/db/session_catalog.h"
 #include "mongo/platform/random.h"
 #include "mongo/stdx/memory.h"
 #include "mongo/util/exit.h"
@@ -216,62 +215,40 @@ bool GlobalCursorIdCache::killCursor(OperationContext* opCtx, CursorId id, bool
         }
     }
 
-    boost::optional<std::pair<LogicalSessionId, TxnNumber>> txnToAbort;
-
     // If this cursor is owned by the global cursor manager, ask it to kill the cursor for us.
     if (CursorManager::isGloballyManagedCursor(id)) {
-        auto statusWithTxnToAbort = globalCursorManager->killCursor(opCtx, id, checkAuth);
+        Status killStatus = globalCursorManager->killCursor(opCtx, id, checkAuth);
         massert(28697,
-                statusWithTxnToAbort.getStatus().reason(),
-                statusWithTxnToAbort.getStatus().code() == ErrorCodes::OK ||
-                    statusWithTxnToAbort.getStatus().code() == ErrorCodes::CursorNotFound);
-        if (!statusWithTxnToAbort.isOK()) {
-            return false;
-        }
-        txnToAbort = statusWithTxnToAbort.getValue();
-    } else {
-        // If not, then the cursor must be owned by a collection. Kill the cursor under the
-        // collection lock (to prevent the collection from going away during the erase).
-        AutoGetCollectionForReadCommand ctx(opCtx, nss);
-        Collection* collection = ctx.getCollection();
-        if (!collection) {
-            if (checkAuth)
-                audit::logKillCursorsAuthzCheck(
-                    opCtx->getClient(), nss, id, ErrorCodes::CursorNotFound);
-            return false;
-        }
-
-        auto statusWithTxnToAbort =
-            collection->getCursorManager()->killCursor(opCtx, id, checkAuth);
-        uassert(16089,
-                statusWithTxnToAbort.getStatus().reason(),
-                statusWithTxnToAbort.getStatus().code() == ErrorCodes::OK ||
-                    statusWithTxnToAbort.getStatus().code() == ErrorCodes::CursorNotFound);
-        if (!statusWithTxnToAbort.isOK()) {
-            return false;
-        }
-        txnToAbort = statusWithTxnToAbort.getValue();
-    }
-
-    // If the cursor has a corresponding transaction, abort that transaction if it is a snapshot
-    // read. This must be done while we are not holding locks.
-    invariant(!opCtx->lockState()->isLocked());
-    if (txnToAbort) {
-        auto session = SessionCatalog::get(opCtx)->getSession(opCtx, txnToAbort->first);
-        if (session) {
-            (*session)->abortIfSnapshotRead(txnToAbort->second);
-        }
+                killStatus.reason(),
+                killStatus.code() == ErrorCodes::OK ||
+                    killStatus.code() == ErrorCodes::CursorNotFound);
+        return killStatus.isOK();
+    }
+
+    // If not, then the cursor must be owned by a collection. Kill the cursor under the
+    // collection lock (to prevent the collection from going away during the erase).
+    AutoGetCollectionForReadCommand ctx(opCtx, nss);
+    Collection* collection = ctx.getCollection();
+    if (!collection) {
+        if (checkAuth)
+            audit::logKillCursorsAuthzCheck(
+                opCtx->getClient(), nss, id, ErrorCodes::CursorNotFound);
+        return false;
     }
 
-    return true;
+    Status eraseStatus = collection->getCursorManager()->killCursor(opCtx, id, checkAuth);
+    uassert(16089,
+            eraseStatus.reason(),
+            eraseStatus.code() == ErrorCodes::OK ||
+                eraseStatus.code() == ErrorCodes::CursorNotFound);
+    return eraseStatus.isOK();
 }
 
 std::size_t GlobalCursorIdCache::timeoutCursors(OperationContext* opCtx, Date_t now) {
     size_t totalTimedOut = 0;
-    std::vector<std::pair<LogicalSessionId, TxnNumber>> txnsToAbort;
 
     // Time out the cursors from the global cursor manager.
-    totalTimedOut += globalCursorManager->timeoutCursors(opCtx, now, &txnsToAbort);
+    totalTimedOut += globalCursorManager->timeoutCursors(opCtx, now);
 
     // Compute the set of collection names that we have to time out cursors for.
     vector<NamespaceString> todo;
@@ -309,17 +286,7 @@ std::size_t GlobalCursorIdCache::timeoutCursors(OperationContext* opCtx, Date_t
             continue;
         }
 
-        totalTimedOut += collection->getCursorManager()->timeoutCursors(opCtx, now, &txnsToAbort);
-    }
-
-    // If the cursors had corresponding transactions, abort the transactions if they are snapshot
-    // reads. This must be done while we are not holding locks.
-    invariant(!opCtx->lockState()->isLocked());
-    for (auto&& txnToAbort : txnsToAbort) {
-        auto session = SessionCatalog::get(opCtx)->getSession(opCtx, txnToAbort.first);
-        if (session) {
-            (*session)->abortIfSnapshotRead(txnToAbort.second);
-        }
+        totalTimedOut += collection->getCursorManager()->timeoutCursors(opCtx, now);
     }
 
     return totalTimedOut;
@@ -538,10 +505,7 @@ bool CursorManager::cursorShouldTimeout_inlock(const ClientCursor* cursor, Date_
     return (now - cursor->_lastUseDate) >= Milliseconds(getCursorTimeoutMillis());
 }
 
-std::size_t CursorManager::timeoutCursors(
-    OperationContext* opCtx,
-    Date_t now,
-    std::vector<std::pair<LogicalSessionId, TxnNumber>>* txnsToAbort) {
+std::size_t CursorManager::timeoutCursors(OperationContext* opCtx, Date_t now) {
     std::vector<std::unique_ptr<ClientCursor, ClientCursor::Deleter>> toDelete;
 
     for (size_t partitionId = 0; partitionId < kNumPartitions; ++partitionId) {
@@ -552,10 +516,6 @@ std::size_t CursorManager::timeoutCursors(
                 // Dispose of the cursor and remove it from the partition.
                 cursor->dispose(opCtx);
                 toDelete.push_back(std::unique_ptr<ClientCursor, ClientCursor::Deleter>{cursor});
-                if (cursor->getTxnNumber()) {
-                    invariant(cursor->getSessionId());
-                    txnsToAbort->emplace_back(*cursor->getSessionId(), *cursor->getTxnNumber());
-                }
                 it = lockedPartition->erase(it);
             } else {
                 ++it;
@@ -762,8 +722,7 @@ void CursorManager::deregisterCursor(ClientCursor* cc) {
     _cursorMap->erase(cc->cursorid());
 }
 
-StatusWith<boost::optional<std::pair<LogicalSessionId, TxnNumber>>> CursorManager::killCursor(
-    OperationContext* opCtx, CursorId id, bool shouldAudit) {
+Status CursorManager::killCursor(OperationContext* opCtx, CursorId id, bool shouldAudit) {
     auto lockedPartition = _cursorMap->lockOnePartition(id);
     auto it = lockedPartition->find(id);
     if (it == lockedPartition->end()) {
@@ -788,23 +747,18 @@ StatusWith<boost::optional<std::pair<LogicalSessionId, TxnNumber>>> CursorManage
         if (shouldAudit) {
             audit::logKillCursorsAuthzCheck(opCtx->getClient(), _nss, id, ErrorCodes::OK);
         }
-        return {boost::none};
+        return Status::OK();
     }
     std::unique_ptr<ClientCursor, ClientCursor::Deleter> ownedCursor(cursor);
 
-    boost::optional<std::pair<LogicalSessionId, TxnNumber>> toReturn;
-    if (ownedCursor->getTxnNumber()) {
-        invariant(ownedCursor->getSessionId());
-        toReturn = std::make_pair(*ownedCursor->getSessionId(), *ownedCursor->getTxnNumber());
-    }
-
     if (shouldAudit) {
         audit::logKillCursorsAuthzCheck(opCtx->getClient(), _nss, id, ErrorCodes::OK);
     }
 
     lockedPartition->erase(ownedCursor->cursorid());
     ownedCursor->dispose(opCtx);
-    return toReturn;
+    return Status::OK();
+    ;
 }
 
 Status CursorManager::checkAuthForKillCursors(OperationContext* opCtx, CursorId id) {
diff --git a/src/mongo/db/cursor_manager.h b/src/mongo/db/cursor_manager.h
index 791007134de..90895407f53 100644
--- a/src/mongo/db/cursor_manager.h
+++ b/src/mongo/db/cursor_manager.h
@@ -132,12 +132,9 @@ public:
     /**
      * Destroys cursors that have been inactive for too long.
      *
-     * Returns the number of cursors that were timed out. If any of the cursors were running in
-     * transactions, appends those transaction IDs to 'txnsToAbort'.
+     * Returns the number of cursors that were timed out.
      */
-    std::size_t timeoutCursors(OperationContext* opCtx,
-                               Date_t now,
-                               std::vector<std::pair<LogicalSessionId, TxnNumber>>* txnsToAbort);
+    std::size_t timeoutCursors(OperationContext* opCtx, Date_t now);
 
     /**
      * Register an executor so that it can be notified of deletions, invalidations, collection
@@ -177,8 +174,7 @@ public:
 
     /**
      * Returns an OK status if the cursor was successfully killed, meaning either:
-     * (1) The cursor was erased from the cursor registry. In this case, we also return the
-     * transaction ID of the transaction the cursor belonged to (if it exists).
+     * (1) The cursor was erased from the cursor registry
      * (2) The cursor's operation was interrupted, and the cursor will be cleaned up when the
      * operation next checks for interruption.
      * Case (2) will only occur if the cursor is pinned.
@@ -188,8 +184,7 @@ public:
      *
      * If 'shouldAudit' is true, will perform audit logging.
      */
-    StatusWith<boost::optional<std::pair<LogicalSessionId, TxnNumber>>> killCursor(
-        OperationContext* opCtx, CursorId id, bool shouldAudit);
+    Status killCursor(OperationContext* opCtx, CursorId id, bool shouldAudit);
 
     /**
      * Returns an OK status if we're authorized to erase the cursor. Otherwise, returns
diff --git a/src/mongo/db/session.cpp b/src/mongo/db/session.cpp
index 5cecce89bd2..53fbc443744 100644
--- a/src/mongo/db/session.cpp
+++ b/src/mongo/db/session.cpp
@@ -671,13 +671,6 @@ void Session::unstashTransactionResources(OperationContext* opCtx) {
     }
 }
 
-void Session::abortIfSnapshotRead(TxnNumber txnNumber) {
-    stdx::lock_guard<stdx::mutex> lg(_mutex);
-    if (_activeTxnNumber == txnNumber && _autocommit) {
-        _abortTransaction(lg);
-    }
-}
-
 void Session::abortArbitraryTransaction() {
     stdx::lock_guard<stdx::mutex> lock(_mutex);
     _abortTransaction(lock);
diff --git a/src/mongo/db/session.h b/src/mongo/db/session.h
index 68cc83a9c14..adad7376b43 100644
--- a/src/mongo/db/session.h
+++ b/src/mongo/db/session.h
@@ -223,12 +223,6 @@ public:
     void unstashTransactionResources(OperationContext* opCtx);
 
     /**
-     * If there is transaction in progress with transaction number 'txnNumber' and _autocommit=true,
-     * aborts the transaction.
-     */
-    void abortIfSnapshotRead(TxnNumber txnNumber);
-
-    /**
      * Commits the transaction, including committing the write unit of work and updating
      * transaction state.
      */
diff --git a/src/mongo/db/session_catalog.cpp b/src/mongo/db/session_catalog.cpp
index 23f830be2e3..48869e4c338 100644
--- a/src/mongo/db/session_catalog.cpp
+++ b/src/mongo/db/session_catalog.cpp
@@ -156,28 +156,6 @@ ScopedSession SessionCatalog::getOrCreateSession(OperationContext* opCtx,
     return ss;
 }
 
-boost::optional<ScopedSession> SessionCatalog::getSession(OperationContext* opCtx,
-                                                          const LogicalSessionId& lsid) {
-    invariant(!opCtx->lockState()->isLocked());
-    invariant(!OperationContextSession::get(opCtx));
-
-    boost::optional<ScopedSession> ss;
-    {
-        stdx::unique_lock<stdx::mutex> ul(_mutex);
-        auto sri = _getSessionRuntimeInfo(ul, opCtx, lsid);
-        if (sri) {
-            ss = ScopedSession(sri);
-        }
-    }
-
-    // Perform the refresh outside of the mutex.
-    if (ss) {
-        (*ss)->refreshFromStorageIfNeeded(opCtx);
-    }
-
-    return ss;
-}
-
 void SessionCatalog::invalidateSessions(OperationContext* opCtx,
                                         boost::optional<BSONObj> singleSessionDoc) {
     uassert(40528,
@@ -244,18 +222,6 @@ std::shared_ptr<SessionCatalog::SessionRuntimeInfo> SessionCatalog::_getOrCreate
     return it->second;
 }
 
-std::shared_ptr<SessionCatalog::SessionRuntimeInfo> SessionCatalog::_getSessionRuntimeInfo(
-    WithLock, OperationContext* opCtx, const LogicalSessionId& lsid) {
-    invariant(!opCtx->lockState()->inAWriteUnitOfWork());
-
-    auto it = _txnTable.find(lsid);
-    if (it == _txnTable.end()) {
-        return nullptr;
-    }
-
-    return it->second;
-}
-
 void SessionCatalog::_releaseSession(const LogicalSessionId& lsid) {
     stdx::lock_guard<stdx::mutex> lg(_mutex);
 
diff --git a/src/mongo/db/session_catalog.h b/src/mongo/db/session_catalog.h
index 1c68fdaa623..657f6baf405 100644
--- a/src/mongo/db/session_catalog.h
+++ b/src/mongo/db/session_catalog.h
@@ -106,18 +106,6 @@ public:
     ScopedSession getOrCreateSession(OperationContext* opCtx, const LogicalSessionId& lsid);
 
     /**
-     * Returns a reference to the specified cached session if it exists, regardless of whether it is
-     * checked-out or not. The returned session is not returned checked-out and is allowed to be
-     * checked-out concurrently.
-     *
-     * The intended usage for this method is to allow cursor destruction that may abort the
-     * transaction to run in parallel with operations for the same session without blocking it.
-     * Because of this, it may not be used from operations which run on a session.
-     */
-    boost::optional<ScopedSession> getSession(OperationContext* opCtx,
-                                              const LogicalSessionId& lsid);
-
-    /**
      * Callback to be invoked when it is suspected that the on-disk session contents might not be in
      * sync with what is in the sessions cache.
      *
@@ -169,15 +157,6 @@ private:
         WithLock, OperationContext* opCtx, const LogicalSessionId& lsid);
 
     /**
-     * May release and re-acquire it zero or more times before returning. The returned
-     * 'SessionRuntimeInfo' is guaranteed to be linked on the catalog's _txnTable as long as the
-     * lock is held. If the requested 'SessionRuntimeInfo' does not exist, returns nullptr.
-     */
-    std::shared_ptr<SessionRuntimeInfo> _getSessionRuntimeInfo(WithLock,
-                                                               OperationContext* opCtx,
-                                                               const LogicalSessionId& lsid);
-
-    /**
      * Makes a session, previously checked out through 'checkoutSession', available again.
      */
     void _releaseSession(const LogicalSessionId& lsid);
diff --git a/src/mongo/dbtests/cursor_manager_test.cpp b/src/mongo/dbtests/cursor_manager_test.cpp
index 9f28a32e143..ee3933dfa35 100644
--- a/src/mongo/dbtests/cursor_manager_test.cpp
+++ b/src/mongo/dbtests/cursor_manager_test.cpp
@@ -303,7 +303,7 @@ TEST_F(CursorManagerTest, ShouldBeAbleToKillPinnedCursor) {
                                                     BSONObj()});
 
     auto cursorId = cursorPin.getCursor()->cursorid();
-    ASSERT_OK(cursorManager->killCursor(_opCtx.get(), cursorId, shouldAudit).getStatus());
+    ASSERT_OK(cursorManager->killCursor(_opCtx.get(), cursorId, shouldAudit));
 
     // The original operation should have been interrupted since the cursor was pinned.
     ASSERT_EQ(pinningOpCtx->checkForInterruptNoAssert(), ErrorCodes::CursorKilled);
@@ -339,7 +339,7 @@ TEST_F(CursorManagerTest, ShouldBeAbleToKillPinnedCursorMultiClient) {
 
     auto killCursorOpCtx = killCursorClient->makeOperationContext();
     invariant(killCursorOpCtx);
-    ASSERT_OK(cursorManager->killCursor(killCursorOpCtx.get(), cursorId, shouldAudit).getStatus());
+    ASSERT_OK(cursorManager->killCursor(killCursorOpCtx.get(), cursorId, shouldAudit));
 
     // The original operation should have been interrupted since the cursor was pinned.
     ASSERT_EQ(pinningOpCtx->checkForInterruptNoAssert(), ErrorCodes::CursorKilled);
@@ -359,15 +359,11 @@ TEST_F(CursorManagerTest, InactiveCursorShouldTimeout) {
                                    repl::ReadConcernLevel::kLocalReadConcern,
                                    BSONObj()});
 
-    std::vector<std::pair<LogicalSessionId, TxnNumber>> txnsToAbort;
-
-    ASSERT_EQ(0UL, cursorManager->timeoutCursors(_opCtx.get(), Date_t(), &txnsToAbort));
-    ASSERT_EQ(0UL, txnsToAbort.size());
+    ASSERT_EQ(0UL, cursorManager->timeoutCursors(_opCtx.get(), Date_t()));
 
     clock->advance(getDefaultCursorTimeoutMillis());
-    ASSERT_EQ(1UL, cursorManager->timeoutCursors(_opCtx.get(), clock->now(), &txnsToAbort));
+    ASSERT_EQ(1UL, cursorManager->timeoutCursors(_opCtx.get(), clock->now()));
     ASSERT_EQ(0UL, cursorManager->numCursors());
-    ASSERT_EQ(0UL, txnsToAbort.size());
 
     cursorManager->registerCursor(_opCtx.get(),
                                   {makeFakePlanExecutor(),
@@ -375,9 +371,8 @@ TEST_F(CursorManagerTest, InactiveCursorShouldTimeout) {
                                    {},
                                    repl::ReadConcernLevel::kLocalReadConcern,
                                    BSONObj()});
-    ASSERT_EQ(1UL, cursorManager->timeoutCursors(_opCtx.get(), Date_t::max(), &txnsToAbort));
+    ASSERT_EQ(1UL, cursorManager->timeoutCursors(_opCtx.get(), Date_t::max()));
     ASSERT_EQ(0UL, cursorManager->numCursors());
-    ASSERT_EQ(0UL, txnsToAbort.size());
 }
 
 /**
@@ -396,9 +391,7 @@ TEST_F(CursorManagerTest, InactivePinnedCursorShouldNotTimeout) {
 
     // The pin is still in scope, so it should not time out.
     clock->advance(getDefaultCursorTimeoutMillis());
-    std::vector<std::pair<LogicalSessionId, TxnNumber>> txnsToAbort;
-    ASSERT_EQ(0UL, cursorManager->timeoutCursors(_opCtx.get(), clock->now(), &txnsToAbort));
-    ASSERT_EQ(0UL, txnsToAbort.size());
+    ASSERT_EQ(0UL, cursorManager->timeoutCursors(_opCtx.get(), clock->now()));
 }
 
 /**
@@ -423,10 +416,8 @@ TEST_F(CursorManagerTest, InactiveKilledCursorsShouldTimeout) {
     // Advance the clock to simulate time passing.
     clock->advance(getDefaultCursorTimeoutMillis());
 
-    std::vector<std::pair<LogicalSessionId, TxnNumber>> txnsToAbort;
-    ASSERT_EQ(1UL, cursorManager->timeoutCursors(_opCtx.get(), clock->now(), &txnsToAbort));
+    ASSERT_EQ(1UL, cursorManager->timeoutCursors(_opCtx.get(), clock->now()));
     ASSERT_EQ(0UL, cursorManager->numCursors());
-    ASSERT_EQ(0UL, txnsToAbort.size());
 }
 
 /**
@@ -451,9 +442,7 @@ TEST_F(CursorManagerTest, InactiveKilledCursorsThatAreStillPinnedShouldNotTimeou
     clock->advance(getDefaultCursorTimeoutMillis());
 
     // The pin is still in scope, so it should not time out.
-    std::vector<std::pair<LogicalSessionId, TxnNumber>> txnsToAbort;
-    ASSERT_EQ(0UL, cursorManager->timeoutCursors(_opCtx.get(), clock->now(), &txnsToAbort));
-    ASSERT_EQ(0UL, txnsToAbort.size());
+    ASSERT_EQ(0UL, cursorManager->timeoutCursors(_opCtx.get(), clock->now()));
 }
 
 /**
@@ -488,20 +477,16 @@ TEST_F(CursorManagerTest, UsingACursorShouldUpdateTimeOfLastUse) {
     // Touch the cursor with id 'usedCursorId' to advance its time of last use.
     cursorManager->pinCursor(_opCtx.get(), usedCursorId).status_with_transitional_ignore();
 
-    std::vector<std::pair<LogicalSessionId, TxnNumber>> txnsToAbort;
-
     // We should be able to time out the unused cursor, but the one we used should stay alive.
     ASSERT_EQ(2UL, cursorManager->numCursors());
     clock->advance(getDefaultCursorTimeoutMillis() - Milliseconds(1));
-    ASSERT_EQ(1UL, cursorManager->timeoutCursors(_opCtx.get(), clock->now(), &txnsToAbort));
+    ASSERT_EQ(1UL, cursorManager->timeoutCursors(_opCtx.get(), clock->now()));
     ASSERT_EQ(1UL, cursorManager->numCursors());
-    ASSERT_EQ(0UL, txnsToAbort.size());
 
     // We should be able to time out the used cursor after one more millisecond.
     clock->advance(Milliseconds(1));
-    ASSERT_EQ(1UL, cursorManager->timeoutCursors(_opCtx.get(), clock->now(), &txnsToAbort));
+    ASSERT_EQ(1UL, cursorManager->timeoutCursors(_opCtx.get(), clock->now()));
     ASSERT_EQ(0UL, cursorManager->numCursors());
-    ASSERT_EQ(0UL, txnsToAbort.size());
 }
 
 /**
@@ -523,27 +508,22 @@ TEST_F(CursorManagerTest, CursorShouldNotTimeOutUntilIdleForLongEnoughAfterBeing
     // Advance the clock to simulate time passing.
     clock->advance(getDefaultCursorTimeoutMillis() + Milliseconds(1));
 
-    std::vector<std::pair<LogicalSessionId, TxnNumber>> txnsToAbort;
-
     // Make sure the pinned cursor does not time out, before or after unpinning it.
     ASSERT_EQ(1UL, cursorManager->numCursors());
-    ASSERT_EQ(0UL, cursorManager->timeoutCursors(_opCtx.get(), clock->now(), &txnsToAbort));
+    ASSERT_EQ(0UL, cursorManager->timeoutCursors(_opCtx.get(), clock->now()));
     ASSERT_EQ(1UL, cursorManager->numCursors());
-    ASSERT_EQ(0UL, txnsToAbort.size());
 
     cursorPin.release();
 
     ASSERT_EQ(1UL, cursorManager->numCursors());
-    ASSERT_EQ(0UL, cursorManager->timeoutCursors(_opCtx.get(), clock->now(), &txnsToAbort));
+    ASSERT_EQ(0UL, cursorManager->timeoutCursors(_opCtx.get(), clock->now()));
     ASSERT_EQ(1UL, cursorManager->numCursors());
-    ASSERT_EQ(0UL, txnsToAbort.size());
 
     // Advance the clock to simulate more time passing, then assert that the now-inactive cursor
     // times out.
     clock->advance(getDefaultCursorTimeoutMillis() + Milliseconds(1));
-    ASSERT_EQ(1UL, cursorManager->timeoutCursors(_opCtx.get(), clock->now(), &txnsToAbort));
+    ASSERT_EQ(1UL, cursorManager->timeoutCursors(_opCtx.get(), clock->now()));
     ASSERT_EQ(0UL, cursorManager->numCursors());
-    ASSERT_EQ(0UL, txnsToAbort.size());
 }
 
 /**
@@ -606,7 +586,7 @@ TEST_F(CursorManagerTestCustomOpCtx, OneCursorWithASession) {
 
     // Remove the cursor from the manager.
     pinned.release();
-    ASSERT_OK(useCursorManager()->killCursor(opCtx.get(), cursorId, false).getStatus());
+    ASSERT_OK(useCursorManager()->killCursor(opCtx.get(), cursorId, false));
 
     // There should be no more cursor entries by session id.
     LogicalSessionIdSet sessions;
@@ -642,7 +622,7 @@ TEST_F(CursorManagerTestCustomOpCtx, MultipleCursorsWithSameSession) {
 
     // Remove one cursor from the manager.
     pinned.release();
-    ASSERT_OK(useCursorManager()->killCursor(opCtx.get(), cursorId1, false).getStatus());
+    ASSERT_OK(useCursorManager()->killCursor(opCtx.get(), cursorId1, false));
 
     // Should still be able to retrieve the session.
     lsids.clear();