The hard drive of my OS died so I had to do a sudden Kubuntu 9.10 to Kubuntu 11.04 upgrade. The OS is actually a fresh install, but the personal data and mysql data were on a different drive, so they were safe.
I am now running the latest mysql 5.1 version of the server. And I look at my mysql data that I still have to import and wonder: where they 5.0 data or 5.1 data? Do I need to do the 5.0 to 5.1 upgrade or not?
https://wiki.ubuntu.com/KarmicKoala/ReleaseNotes#MySQL_upgrade
Quoting the above page:
In Ubuntu 9.10 MySQL 5.1 has been promoted as the default MySQL server. MySQL 5.0 is still available from the universe repository though. Performing an upgrade via update-manager will correctly handle the transition from MySQL 5.0 to MySQL 5.1. However using a dist-upgrade will not: mysql-server-5.0 will be upgraded instead of being replaced by mysql-server-5.1. If MySQL 5.0 needs to be kept the mysql-server and mysql-client packages should be removed before the upgrade is started.
I completely forgot how I performed the upgrade to Kubuntu 9.10 from the previous release, so, reading the above, I am not sure whether my data was properly upgraded or not to 5.1.
How can I tell? What's the difference between the two versions (as far as the data is concerned)?
I had problems configuring mysql because of a non-standard data dir. Apparently, it was a problem with apparmor, which is now solved: I had to add the data dir path to the list of authorized paths for mysql within the apparmor config file.
In the data dir, I found the following files which indicates that the data was probably mysql 5.1 compatible:
Most importantly, mysql and phpmyadmin seem to work perfectly, now, and I can browse all the data. I have a backup of the whole datadir just in case.
Also, as suggested in the comments, I performed the upgrade anyway: it didn't harm anything and I found a bunch of tables that needed to be repaired:
Thank you to the people who commented, trying to help. :)