mariadb <10.1.30 hangs on FLUSH LOGS
Under some circumstances, MariaDB hangs on FLUSH LOGS (a command used to rotate error logs or to enforce the start of a new binary log).
This bug was fixed in MariaDB 10.1.30, and given the its impact it might be worth to update MariaDB to this version in the stable alpine-3.7.
https://jira.mariadb.org/browse/MDEV-10809
(from redmine: issue id 8402, created on 2018-01-15)