Percona Server does not release memory after executing query that required full-text index.
Tested against 5.7.24-26, this issue is not reproducible with upstream or PS 8. This is reproducible with thread_cache_size=0.
Steps to reproduce:
1. Create a test table.
2. Populate it with data:
3. Start monitoring memory usage (pidstat -p pid -r 1 1000, for example)
4. Start select query in a loop:
5. Check current MySQL memory usage
- It starts growing:
and finally, it reaches a maximum point after it is not released back even if queries from point 3 are finished already:
What's interesting, executing the same amount of 'dummy' queries:
caused MySQL to release back its memory: