Hello.
MongoDB 5.0.17 Community.
We see nearly the same behavior of storage allocation and use for a number of collections with TTL indexes. The storageSize field value returned by the $collStats aggregation stage constantly grows despite the size and count values stay nearly the same.
For example, after subsequent resynchronization of one of our collections we have:
count ~ 100M, size ~ 170 GB, storageSize ~ 90 GB
Having nearly the same count & size every time we see, that storageSize grows slowly but continuously, and finally we get storageSize ~ 400GB, when we have to run another recync cycle to decrease storageSize for this and a number of other collections.
We have never seen such a behavior on our 4.4 version.
What could be a reason of such a strange storage management in 5.0?