Joblist thread pool doesn't release threads occupied by JobList steps if mariadb client breaks its connection before the JobList step finishes.
To reproduce one should follow these steps:
- Joblist thread pool debugging must be enabled in Columnstore.xml first
- run select * from tpch1c.lineitem and hit ctrl+c before the query returns the result set.
- then number of Active threads in
/var/log/mariadb/columnstore/trace/ThreadPool_ExeMgrJobList.log must be >=
10 and it won't decrease.