Error upgrading mariadb-10.1 to 10.2 on debian 9

Question

What about this error? upgrading on debian 9 with plesk from mariadb 10.1 to 10.2

Any clue how to fix it and continue upgrade?

apt install mariadb-server-10.2
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following additional packages will be installed:
  libmariadb3 libmariadbclient18 mariadb-client-10.2 mariadb-client-core-10.2 mariadb-server-core-10.2
Suggested packages:
  mariadb-test netcat-openbsd tinyca
Recommended packages:
  libhtml-template-perl
The following packages will be REMOVED:
  default-mysql-server mariadb-client-10.1 mariadb-client-core-10.1 mariadb-server-10.1 mariadb-server-core-10.1
The following NEW packages will be installed:
  libmariadb3 mariadb-client-10.2 mariadb-client-core-10.2 mariadb-server-10.2 mariadb-server-core-10.2
The following packages will be upgraded:
  libmariadbclient18
1 upgraded, 5 newly installed, 5 to remove and 10 not upgraded.
Need to get 0 B/11.8 MB of archives.
After this operation, 46.1 MB disk space will be freed.
Do you want to continue? [Y/n] y
Preconfiguring packages ...
(Reading database ... 97530 files and directories currently installed.)
Removing default-mysql-server (1.0.2) ...
dpkg: mariadb-server-10.1: dependency problems, but removing anyway as you requested:
 plesk-mysql-server depends on virtual-mysql-server | mysql-server; however:
  Package virtual-mysql-server is not installed.
  Package mariadb-server-10.1 which provides virtual-mysql-server is to be removed.
  Package mysql-server is not installed.
 plesk-mysql-server depends on virtual-mysql-server | mysql-server; however:
  Package virtual-mysql-server is not installed.
  Package mariadb-server-10.1 which provides virtual-mysql-server is to be removed.
  Package mysql-server is not installed.
 plesk-mysql-server depends on virtual-mysql-server | mysql-server; however:
  Package virtual-mysql-server is not installed.
  Package mariadb-server-10.1 which provides virtual-mysql-server is to be removed.
  Package mysql-server is not installed.
 plesk-mysql-server depends on virtual-mysql-server | mysql-server; however:
  Package virtual-mysql-server is not installed.
  Package mariadb-server-10.1 which provides virtual-mysql-server is to be removed.
  Package mysql-server is not installed.

Removing mariadb-server-10.1 (10.1.47-0+deb9u1) ...
(Reading database ... 97403 files and directories currently installed.)
Preparing to unpack .../mariadb-server-10.2_10.2.36+maria~stretch_amd64.deb ...
/var/lib/mysql: found previous version 10.1
Unpacking mariadb-server-10.2 (10.2.36+maria~stretch) ...
dpkg: error processing archive /var/cache/apt/archives/mariadb-server-10.2_10.2.36+maria~stretch_amd64.deb (--unpack):
 trying to overwrite '/usr/bin/mysql_install_db', which is also in package mariadb-server-core-10.1 10.1.47-0+deb9u1
dpkg-deb: error: subprocess paste was killed by signal (Broken pipe)
Errors were encountered while processing:
 /var/cache/apt/archives/mariadb-server-10.2_10.2.36+maria~stretch_amd64.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

Answer 1

You upgraded mariadb-10.1 from the Debian Stretch repo with mariadb-10.2 from the mariadb.org repo. One Problem seems to be that the plesk packages want virtual-mysql-server installed which get pulled in by the mariadb-10.1 packages from the Debian Stretch repo but not by the ones from the mariadb.org repo. That already indicates that it might be a bad idea to upgrade.

The problem that halts the installation is that the file /usr/bin/mysql_install_db is part of the mariadb-server-core package in mariadb-10.1 but part of mariadb-server package in mariadb-10.2. Since mariadb-server package gets upgraded first, the file is still there and owned by another package.

The installation would most likely succeed if you'd remove the mariadb-server-core-10.1 package (and therefore all its dependencies) before upgrading to mariadb-10.2. But this would still leave you with the plesk dependency problem.