compact_range ineffective?

[mrx23dot]

Is it me or db.compact_range() doesn't do anything?

It returns instantly on 10GB database, and it's far from optimal content wise.
(I get 2x speed up after iterating end recreating it)

[mrx23dot]

or is it async? there is no doc here https://github.com/google/leveldb/blob/main/doc/index.md

from changelog: 'LevelDB uses for compaction calls back into Python code in that case.' although it was regarding comparators