SERVER-49895 Expose getLatestOplogTimestamp() in aggregation cursor command responses on oplog

1 files changed, 11 insertions, 1 deletions

diff --git a/src/mongo/db/exec/collection_scan.h b/src/mongo/db/exec/collection_scan.h
index 3d79915b0fe..b67d8cd6603 100644
--- a/src/mongo/db/exec/collection_scan.h
+++ b/src/mongo/db/exec/collection_scan.h
@@ -35,6 +35,7 @@
 #include "mongo/db/exec/requires_collection_stage.h"
 #include "mongo/db/matcher/expression_leaf.h"
 #include "mongo/db/record_id.h"
+#include "mongo/s/resharding/resume_token_gen.h"
 
 namespace mongo {
 
@@ -74,7 +75,16 @@ public:
     }
 
     BSONObj getPostBatchResumeToken() const {
-        return _params.requestResumeToken ? BSON("$recordId" << _lastSeenId.repr()) : BSONObj();
+        // Return a resume token compatible with resumable initial sync.
+        if (_params.requestResumeToken) {
+            return BSON("$recordId" << _lastSeenId.repr());
+        }
+        // Return a resume token compatible with resharding oplog sync.
+        if (_params.shouldTrackLatestOplogTimestamp) {
+            return ResumeTokenOplogTimestamp{_latestOplogEntryTimestamp}.toBSON();
+        }
+
+        return {};
     }
 
     std::unique_ptr<PlanStageStats> getStats() final;