We found the last timestamp value is keyed by namespace(db.collection), however for mongo, one collection can be stored in multiple shards. In this situation, last timestamp may from shard A, and the latest timestamp may from shard B. When above two timestamp mismatch, the STALE happened.
We found the last timestamp value is keyed by namespace(db.collection), however for mongo, one collection can be stored in multiple shards. In this situation, last timestamp may from shard A, and the latest timestamp may from shard B. When above two timestamp mismatch, the STALE happened.