Apt performs some actions multiple times when once would suffice

[David Jaša]

I've noticed that if I just ask aptitude to purge kernel packages (packages linux-image-, linux-restricted-modules- and linux-ubuntu-modules-2.6.24-11-generic), apt/dpkg is invoking twice:

1) update-initramfs which doesn't need to be invoked at all (or once at the end when it's got nothing to do)
2) update-grub which needs to be invoked just once at the end

(you can see output of aptitude in attachment). I think that this is reason, why has bug #44535 so bad impact.

[David Jaša (dejv)]

I think it's neither aptitude's nor linux's bug. There are certain actions, which can be run just at the end of apt's actions (update-grub, scrollkeeper-update and maybe others), but there's no way to tell apt to do this, so packager have tu run such action during "setting up" stage of package.

[Leann Ogasawara (leannogasawara)]

Hi David,

Per your last comment, do you want to keep this report open or close it out? Thanks.

[David Jaša (dejv)]

This is bug in debian package management but I'm not sure on which level. And I'd like to keep it opened until it's fixed. :-)

[Leann Ogasawara (leannogasawara)]

The Ubuntu Kernel Team is planning to move to the 2.6.27 kernel for the upcoming Intrepid Ibex 8.10 release. As a result, the kernel team would appreciate it if you could please test this newer 2.6.27 Ubuntu kernel. There are one of two ways you should be able to test:

1) If you are comfortable installing packages on your own, the linux-image-2.6.27-* package is currently available for you to install and test.

--or--

2) The upcoming Alpha5 for Intrepid Ibex 8.10 will contain this newer 2.6.27 Ubuntu kernel. Alpha5 is set to be released Thursday Sept 4. Please watch http://www.ubuntu.com/testing for Alpha5 to be announced. You should then be able to test via a LiveCD.

Please let us know immediately if this newer 2.6.27 kernel resolves the bug reported here or if the issue remains. More importantly, please open a new bug report for each new bug/regression introduced by the 2.6.27 kernel and tag the bug report with 'linux-2.6.27'. Also, please specifically note if the issue does or does not appear in the 2.6.26 kernel. Thanks again, we really appreicate your help and feedback.

[Przemek K. (azrael)]

Definitely not a Linux kernel bug. It's a bug in apt or dpkg. One of them should check for such repeatable actions invoked by packages and run them once at the end.

[Evgeny Kapun (abacabadabacaba)]

This is bug in apt. This is because apt-get invokes dpkg once for each installed/removed package instead of invoking it just once for the whole operation.

[Tomas Van Verrewegen (tomasvanverrewegen)]

I think this is a reasonably serious bug. I know it has been bugging me for a long time already :)
Example: I just removed 4 obsolete kernel packages, which should be a fairly straightforward operation, but it took more than 5 minutes to complete. Running update-grub with 4 kernels, 3 kernels, 2 kernels, ... It should have finished in 30 seconds. that's a HUGE difference.

[Raphaël Hertzog (hertzog)]

The required support already exists with triggers. There's no need for any improvement to dpkg. Marking this bug as invalid for dpkg.

[Julian Andres Klode (juliank)]

We use triggers now. Not to full extent, though, as there are some issues, but those are not APT issues.