Debian series upgrade (e.g. 5.5->5.6) runs mysql_install_db

[Glenn Pratt]

In #1507812, mysql_install_db was skipped on upgrade.

https://bugs.launchpad.net/percona-server/+bug/1507812

https://github.com/percona/percona-server/pull/366

However, it appears the postinst script is not aware that installing 5.6 over 5.5 is an upgrade and it still runs.

See this gist for full reproduction:

https://gist.github.com/glennpratt/319ca1440ae57d7f4060d8598b54997d

Here is a snip of the output with logging I added:

+ apt-get install -y --allow-unauthenticated percona-server-server-5.6=5.6.32-78.1-1.xenial~1
...
The following packages were automatically installed and are no longer required:
  libperconaserverclient18 percona-server-common-5.5
Use 'sudo apt autoremove' to remove them.
The following additional packages will be installed:
  libperconaserverclient18.1 percona-server-client-5.6
  percona-server-common-5.6
Suggested packages:
  tinyca
The following packages will be REMOVED:
  percona-server-client-5.5 percona-server-server-5.5
The following NEW packages will be installed:
  libperconaserverclient18.1 percona-server-client-5.6
  percona-server-common-5.6 percona-server-server-5.6
0 upgraded, 4 newly installed, 2 to remove and 4 not upgraded.
...
Setting up percona-server-server-5.6 (5.6.32-78.1-1.xenial~1) ...
Installing new version of config file /etc/init.d/mysql ...
<13>Oct 9 12:27:22 bug1507812: $0 == /var/lib/dpkg/info/percona-server-server-5.6.postinst
<13>Oct 9 12:27:22 bug1507812: $1 == configure
<13>Oct 9 12:27:22 bug1507812: $2 ==
<13>Oct 9 12:27:22 bug1507812: running mysql_install_db

[Tomislav Plavcic (tplavcic)]

There's a simple explanation why this could happen, the logic checks if it's an package upgrade and then doesn't run the mysql_install_db. But Percona server packages are called differently and have a suffix (-5.5/5.6/5.7) by major version since we only have one repository and so we can't put the same package name in that repo for every major version. So the apt/dpkg doesn't realize that it's an upgrade (package name is different) and thinks we are just making a normal installation.
I didn't test this but from what I see it should be like that.

Also I think you made a mistake in the bug report title - most probably it shouldn't be "Minor version upgrades..." but instead "Major version upgrades..." - so if you agree feel free to fix it.
Not sure how it's going to be fixed but the logic in that "if" check will need to be changed.

[Glenn Pratt (glennpratt)]

I agree that is the likely issue.

I might be confused, but 5.5 -> 5.6 is a minor version. (MAJOR.MINOR.PATCH)

I'm def. interested in how we detect this situation properly. Any direction there would be very helpful!

[Tomislav Plavcic (tplavcic)]

Sorry about the misunderstanding on versions, you are right about how we look at the full version number, but when upgrading from PS 5.5->5.6->5.7 due to the amount of changes we consider those to be major upgrades and upgrades from eg. 5.6.30->5.6.31 (smaller upgrades in the same series) only minor upgrades. I hope it makes sense.

[Glenn Pratt (glennpratt)]

Sorry, #4 was a mistake. Please ignore.

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PS-3576