We run a few sharded clusters and many replicasets. Our customers don't use TTL Indexes.
Will there be a better performance if we disable background thread that is responsible for deleting documents from collections with TTL indexes?
mongod --setParameter ttlMonitorEnabled=false
I found an old (2013) Time to live (TTL) slows down mongod post on mailing list. I don't know if this is a edge case or general optimizion.
Quote from SERVER-10033
May be used to stop TTL deletes if the system is under extreme load or during an outage/corruption investigation. A single global (or per-DB) setting would be easier than having to update or drop all TTL indexes.