SERVER-36956 SnapshotTooOld errors will always increase the snapshot history window size

1 files changed, 6 insertions, 4 deletions

diff --git a/src/mongo/db/periodic_runner_job_decrease_snapshot_cache_pressure.h b/src/mongo/db/periodic_runner_job_decrease_snapshot_cache_pressure.h
index fca8b832fbf..1b6c2e65b18 100644
--- a/src/mongo/db/periodic_runner_job_decrease_snapshot_cache_pressure.h
+++ b/src/mongo/db/periodic_runner_job_decrease_snapshot_cache_pressure.h
@@ -34,13 +34,15 @@ namespace mongo {
 class ServiceContext;
 
 /**
- * Periodically checks for storage engine cache pressure to determine whether the maintained
- * snapshot history window target setting should be decreased. Maintaining too much snapshot and
- * write history can slow down the system. Runs once every checkCachePressurePeriodSeconds.
+ * Periodically checks whether there has been any storage engine cache pressure and SnapshotTooOld
+ * errors to determine whether the maintained snapshot history window target setting should be
+ * decreased. If there has been cache pressure and no new SnapshotTooOld errors in the last period,
+ * then the target window size will be decrease. Maintaining too much snapshot and write history can
+ * slow down the system. Runs once every decreaseHistoryIfNotNeededPeriodSeconds.
  *
  * This function should only ever be called once, during mongod server startup (db.cpp).
  * The PeriodicRunner will handle shutting down the job on shutdown, no extra handling necessary.
  */
-void startPeriodicThreadToDecreaseSnapshotHistoryCachePressure(ServiceContext* serviceContext);
+void startPeriodicThreadToDecreaseSnapshotHistoryIfNotNeeded(ServiceContext* serviceContext);
 
 }  // namespace mongo