SERVER-42343 drop all snapshots on transition from a readable state to a non-readable one

This avoids accumulating unnecessary historical information in the storage engine while
we are in a non-readable state.

1 files changed, 6 insertions, 0 deletions

diff --git a/src/mongo/db/repl/replication_coordinator_impl.cpp b/src/mongo/db/repl/replication_coordinator_impl.cpp
index f532032a309..a1635f6b795 100644
--- a/src/mongo/db/repl/replication_coordinator_impl.cpp
+++ b/src/mongo/db/repl/replication_coordinator_impl.cpp
@@ -2694,6 +2694,12 @@ ReplicationCoordinatorImpl::_updateMemberStateFromTopologyCoordinator_inlock() {
         _externalState->forceSnapshotCreation();
     }
 
+    if (!newState.readable() && _memberState.readable()) {
+        // Avoid accumulating history after transitioning to a non-readable state.
+        log() << "Dropping all snapshots on transition from " << _memberState << " to " << newState;
+        _dropAllSnapshots_inlock();
+    }
+
     if (newState.rollback()) {
         // When we start rollback, we need to drop all snapshots since we may need to create
         // out-of-order snapshots. This would be necessary even if the SnapshotName was completely