Post TTL index document expiry delete , space is not freed up

Working with Data
1

Using MongoDB 4.2.9, Have query on TTL index. Post expiry document deletion does it free space in 4.2.9 version?

2

normally no. db can sometimes grow very fast, so to better deal with that, db systems usually manage freed space on their own instead of returning to OS. So that later they can allocate more space for new data faster.

But you need to double check the official doc of course.