[debian-mysql] Support for MySQL 5.0 and 5.1

[Mathias Gug]

Hi Norbert,

On Thu, Jan 15, 2009 at 09:22:47AM +0100, Norbert Tretkowski wrote:
> Am Mittwoch, den 14.01.2009, 13:45 -0500 schrieb Mathias Gug:
> > I was wondering what the plan was for MySQL 5.0 and 5.1 in Debian
> > (after lenny is released). Do you plan to provide both 5.0 and 5.1?
> 
> I don't plan to have 5.0 and 5.1 in unstable at the same time. Maybe
> I'll change my mind about that, so we'll have 5.0 and 5.1 in unstable at
> least for a while, but I definitely don't want to have 5.0 and 5.1 in
> our next release.

Understood. The situation in Ubuntu for now (and probably for Jaunty due
in April 2009) is that both 5.0 and 5.1 are in the archive (5.0 in main
and 5.1 in universe). If you plan to support 5.0 and 5.1 in unstable at
least for a while how would do it?

The first option is to make them conflict with each other: you can only
have 5.0 or 5.1 installed on a system. That almost works now: there is
only one option (skip-bdb) in /etc/mysql/my.cnf from 5.0 that isn't
supported by 5.1.

The second option is to change the MySQL infrastructure to support both
5.0 and 5.1 installed at the same time. This is what postgresql does.
Here is an excerpt of the architecture overview page:

  Each versioned package installs into /usr/lib/postgresql/version. In
  order to allow users easily to select the right version and cluster
  when working, the postgresql-common package provides the pg_wrapper
  program, which reads the  per-user and system wide configuration file
  and forks the correct executable with the correct library versions
  according to those preferences.  /usr/bin provides executables
  soft-linked to pg_wrapper.

More information can be found in the architecture.html file from the postgresql-common package.

Supporting both 5.0 and 5.1 installed at the same time is a requirement
to run two KDE applications: amarok (music player) and akonadi (pim
manager). amarok uses the 5.1 embedded mysqld library while akonadi
starts its own 5.0 mysqld process.

It seems that splitting the mysql-server-5.1 in a different packages
could cover the amarok use case: provide a package for the embedded
server library (in mysql-server-common-5.1 for ex) and the init script
in mysql-server-5.1). I haven't investigated how to support the second
use case.

One thing that is sure is that supporting both 5.0 and 5.1 installed would
require significant work in both 5.0 and 5.1 packages. That's why I'm
seeking input from the Debian maintainer team. What's your opinion on
this?

-- 
Mathias Gug
Ubuntu Developer  http://www.ubuntu.com