The range deleter observer is currently registering tasks on insert and on update , slightly before the entry oplog entry is actually committed.

This may lead to an improbable but still possible race condition:

1. The observer registers the task with "whenToClean=now"
2. The range deleter service executor picks the task and executes it right away
3. No orphan gets deleted because the range deletion document is not visible yet, the task gets unscheduled
4. The range deletion document gets committed

Purpose of this ticket is to delay the registration after the commit actually happens (basically making sure 4 always happens first). This can be done by registering an onCommit event similarly to the way it's done for the critical section.