In rollback to stable, we need to open all the dhandles to check whether any work is required to rollback the particular table. If we have a lot of files in the database, we would have a lot of dhandles open in WiredTiger after rollback to stable. The following checkpoint after rollback to stable then would become very expensive in this case. Some customers with large dhandles are experiencing performance issues during shut down and startup since upgrading to mongodb 4.4.
We need to figure out a solution to reduce the checkpoint overhead caused by the dhandles opened by rollback to stable.