Hello! I tested the scenario where a system had mariadb-server-10.0 et al installed in Jessie, and then upgrades to Stretch. In Streatch mariadb-server-10.0 is replaced by 10.1 but not purged.
Then I ran $ apt-get purge mariadb-*-10.0 The following packages will be REMOVED: mariadb-client-10.0* mariadb-server-10.0* 0 upgraded, 0 newly installed, 2 to remove and 0 not upgraded. After this operation, 0 B of additional disk space will be used. Do you want to continue? [Y/n] y (Reading database ... 45411 files and directories currently installed.) Purging configuration files for mariadb-server-10.0 (10.0.29-0+deb8u1) ... Purging configuration files for mariadb-client-10.0 (10.0.29-0+deb8u1) ... root@purge-test:~# ls -la /etc/init.d/mysql -rwxr-xr-x 1 root root 5929 Jan 19 20:54 /etc/init.d/mysql root@purge-test:~# grep mysql /var/log/syslog | tail -n 5 Jan 25 10:34:18 mysqld_safe[27837]: 2017-01-25 10:34:18 139642039747136 [Note] /usr/sbin/mysqld (mysqld 10.1.21-MariaDB-2) starting as process 27836 ... Jan 25 10:34:22 mysqld[28032]: 2017-01-25 10:34:22 140657493631552 [Note] /usr/sbin/mysqld (mysqld 10.1.21-MariaDB-2) starting as process 28032 ... (nothing around 10:40) The init file remained after purge and mysqld did not restart. I even had a console open to mysqld during the purge and it did not close/restart. I am happy to accept patches though for this issue if somebody else can better reproduce the problem and then verify that the patches work when written.
