SERVER-34215 Clear oplog truncate after point when clearing initial sync flag

(cherry picked from commit f320f151e0a709dafc8f8359ab7fab303a7f74a9)

3 files changed, 32 insertions, 0 deletions

diff --git a/src/mongo/db/repl/replication_consistency_markers_impl.cpp b/src/mongo/db/repl/replication_consistency_markers_impl.cpp
index 5d0b1f70a4a..1486d1ab397 100644
--- a/src/mongo/db/repl/replication_consistency_markers_impl.cpp
+++ b/src/mongo/db/repl/replication_consistency_markers_impl.cpp
@@ -162,6 +162,11 @@ void ReplicationConsistencyMarkersImpl::clearInitialSyncFlag(OperationContext* o
 
     _updateMinValidDocument(opCtx, update);
 
+    // Make sure to clear the oplogTrucateAfterPoint in case it is stale. Otherwise, we risk the
+    // possibility of deleting oplog entries that we want to keep. It is safe to clear this
+    // here since we are consistent at the top of our oplog at this point.
+    setOplogTruncateAfterPoint(opCtx, Timestamp());
+
     if (getGlobalServiceContext()->getStorageEngine()->isDurable()) {
         opCtx->recoveryUnit()->waitUntilDurable();
         replCoord->setMyLastDurableOpTime(time);
diff --git a/src/mongo/db/repl/replication_consistency_markers_impl_test.cpp b/src/mongo/db/repl/replication_consistency_markers_impl_test.cpp
index 864a5b6601f..d20a8d64423 100644
--- a/src/mongo/db/repl/replication_consistency_markers_impl_test.cpp
+++ b/src/mongo/db/repl/replication_consistency_markers_impl_test.cpp
@@ -193,6 +193,32 @@ TEST_F(ReplicationConsistencyMarkersTest, GetMinValidAfterSettingInitialSyncFlag
     ASSERT(consistencyMarkers.getOplogTruncateAfterPoint(opCtx).isNull());
 }
 
+TEST_F(ReplicationConsistencyMarkersTest, ClearInitialSyncFlagResetsOplogTruncateAfterPoint) {
+    auto minValidNss = makeNamespace(_agent, "minValid");
+    auto oplogTruncateAfterPointNss = makeNamespace(_agent, "oplogTruncateAfterPoint");
+
+    ReplicationConsistencyMarkersImpl consistencyMarkers(
+        getStorageInterface(), minValidNss, oplogTruncateAfterPointNss);
+    auto opCtx = getOperationContext();
+    ASSERT(consistencyMarkers.createInternalCollections(opCtx).isOK());
+    consistencyMarkers.initializeMinValidDocument(opCtx);
+
+    ASSERT(consistencyMarkers.getOplogTruncateAfterPoint(opCtx).isNull());
+    ASSERT_FALSE(consistencyMarkers.getInitialSyncFlag(opCtx));
+
+    // Set the oplog truncate after point and verify it has been set correctly.
+    OpTime endOpTime({Seconds(456), 0}, 1LL);
+    consistencyMarkers.setOplogTruncateAfterPoint(opCtx, endOpTime.getTimestamp());
+    ASSERT_EQ(consistencyMarkers.getOplogTruncateAfterPoint(opCtx), endOpTime.getTimestamp());
+
+    // Clear the initial sync flag.
+    consistencyMarkers.clearInitialSyncFlag(opCtx);
+    ASSERT_FALSE(consistencyMarkers.getInitialSyncFlag(opCtx));
+
+    // Make sure the oplog truncate after point no longer exists.
+    ASSERT(consistencyMarkers.getOplogTruncateAfterPoint(opCtx).isNull());
+}
+
 TEST_F(ReplicationConsistencyMarkersTest, ReplicationConsistencyMarkers) {
     auto minValidNss = makeNamespace(_agent, "minValid");
     auto oplogTruncateAfterPointNss = makeNamespace(_agent, "oplogTruncateAfterPoint");
diff --git a/src/mongo/dbtests/storage_timestamp_tests.cpp b/src/mongo/dbtests/storage_timestamp_tests.cpp
index f2ac40ad101..ecb3acea951 100644
--- a/src/mongo/dbtests/storage_timestamp_tests.cpp
+++ b/src/mongo/dbtests/storage_timestamp_tests.cpp
@@ -1568,6 +1568,7 @@ public:
 
         repl::ReplicationConsistencyMarkersImpl consistencyMarkers(
             repl::StorageInterface::get(_opCtx));
+        ASSERT(consistencyMarkers.createInternalCollections(_opCtx).isOK());
         consistencyMarkers.initializeMinValidDocument(_opCtx);
         consistencyMarkers.setInitialSyncFlag(_opCtx);