SERVER-41560 default the snapshot window size to 0 when running with the WT inMemory storage engine

1 files changed, 5 insertions, 1 deletions

diff --git a/src/mongo/db/db.cpp b/src/mongo/db/db.cpp
index 3ba6eb79169..652355ee908 100644
--- a/src/mongo/db/db.cpp
+++ b/src/mongo/db/db.cpp
@@ -611,7 +611,11 @@ ExitCode _initAndListen(int listenPort) {
     // release periodically in order to avoid storage cache pressure build up.
     if (storageEngine->supportsReadConcernSnapshot()) {
         PeriodicThreadToAbortExpiredTransactions::get(serviceContext)->start();
-        PeriodicThreadToDecreaseSnapshotHistoryCachePressure::get(serviceContext)->start();
+        // The inMemory engine is not yet used for replica or sharded transactions in production so
+        // it does not currently maintain snapshot history. It is live in testing, however.
+        if (!storageEngine->isEphemeral() || getTestCommandsEnabled()) {
+            PeriodicThreadToDecreaseSnapshotHistoryCachePressure::get(serviceContext)->start();
+        }
     }
 
     // Set up the logical session cache