What does that "Slow Operation" mean in Replication

Mat_Chan · 2024-12-28T13:29:04.497Z

According to the documentation, it says

Secondary members of a replica set now log oplog entries that take longer than the slow operation threshold to apply.

I wonder what that means exactly? Currently I understand we can have primary node and secondary members for a replica set where secondary members rely on oplog for write operation in order to sync information.

chris · 2024-12-29T01:08:20.158Z

Hi @Mat_Chan

Replication in a MongoDB replica set is logical replication. The operations replicated have to be applied to the secondary. If the duration to complete the update takes longer than the configured slowms threshold(default 100ms) then that will be logged.

Mat_Chan · 2024-12-30T16:04:59.721Z

Mat_Chan:

Secondary members of a replica set now log oplog entries that take longer than the slow operation threshold to apply.

Hi @chris,

So you mean by default the secondary will reference the oplog from primary for replication but when the operation exceeds the configured slowms threshold then the secondary itself will log a separate oplog?