update-manager hangs for 10 seconds

[Chris Moore]

once I've applied all the outstanding patches, and the update manager is telling me my system is up to date, if I click 'reload' at the bottom, the following happens:

1. after a pause of about a second, a small window called "downloading package information" appears. it very quickly verifies that there's nothing new to download, and disappears again after about a second.

2. the "software updates" window (where I clicked 'reload') is all greyed out. none of the buttons are operational, and nothing appears to be happening. there's no modal sub-window, no progress bar, no CPU in use, no disk activity, nothing. this lasts for 8 to 10 seconds - long enough to have me reaching for the web browser to report that it's hung

3. after 8 to 10 seconds a new small window appears, called "checking for available updates". the progress bar zips from left to right 4 times, "building dependancy tree", then the small window goes away leaving me with the "software updates" window. the "help", "reload" and "close" buttons are now available again.

The bug is that step 2 hangs for 8 to 10 seconds, apparently doing nothing, with no "please wait" message, or anything to suggest that it hasn't crashed. It doesn't look good for an important application like the update manager to be hanging like this.

[Chris Moore (dooglus)]

This is what I see for the 8 to 10 seconds that the application is hanging.

[Chris Moore (dooglus)]

I should have mentioned. This happens with at least versions 0.42.2ubuntu6 and 0.42.2ubuntu5 of update-manager, and the machine I'm using is a 2.2GHz Intel P4 laptop with a 6Mb net connection.

[Chris Moore (dooglus)]

For completeness, here's how long apt-get commands take to run from the command line:

$ time sudo apt-get update; time sudo apt-get upgrade; time sudo apt-get dist-upgrade

[...]
Hit http://archive.ubuntu.com dapper/multiverse Sources
Fetched 1B in 0s (2B/s)
Reading package lists... Done

real 0m0.719s
user 0m0.063s
sys 0m0.033s
Reading package lists... Done
Building dependency tree... Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

real 0m0.766s
user 0m0.558s
sys 0m0.085s
Reading package lists... Done
Building dependency tree... Done
Calculating upgrade...Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

real 0m0.652s
user 0m0.517s
sys 0m0.094s

ie. each is less than a second.

[Chris Moore (dooglus)]

I've looked in to this a bit more and found that this command is the one which is hanging:

  sudo /usr/sbin/synaptic --hide-main-window --non-interactive --parent-window-id 29360131 --update-at-startup

And contrary to my previous claim, the CPU is flat out (100%) for the whole time it's hanging.

[Chris Moore (dooglus)]

chris@chrislap:~$ time sudo /usr/sbin/synaptic --hide-main-window --non-interactive --parent-window-id 29360131 --update-at-startup

real 0m11.276s
user 0m8.391s
sys 0m0.280s

[Chris Moore (dooglus)]

... but is it safe?

I found that when synaptic is run to update the package list, it updates the package list very quickly and then spends a lot of time sorting a big list of package names into alphabetical order 13 times. Yes, the same list is sorted 13 times. It seems like the results of the sort aren't even used, so my patch simply returns immediately after updating the package list if the '--hide-main-window' flag is specified to synaptic.

Is that safe?

[Chris Moore (dooglus)]

I see the same list of 18603 packages being sorted 13 times.

Here are the 13 backtraces, one per sort, caused when I run:

  sudo ./synaptic --hide-main-window --non-interactive --parent-window-id 29360131 --update-at-startup

with these 2 lines in my sources.list:

  deb http://archive.ubuntu.com/ubuntu/ dapper main restricted universe multiverse
  deb-src http://archive.ubuntu.com/ubuntu/ dapper main restricted universe multiverse

[Sebastian Heinlein (glatzor)]

Thanks for your detailed bug report.

I hope that you haven't been discouraged by the huge lack of response. Time is very rare at the moment, but your bug report will be considered.

Regards,

Sebastian

[Adam Niedling (krychek)]

That "hang" is about 2-3 seconds for me in Intrepid. The mouse pointer also suggests that it didn't freeze. I don't think this is a bug. Is this still an issue for you? If so which version of Ubuntu are you using now?

[Chris Moore (dooglus)]

On Thu, Nov 27, 2008 at 7:25 PM, Adam Niedling <email address hidden> wrote:
> Is
> this still an issue for you? If so which version of Ubuntu are you using
> now?

It's no longer an issue for me. I got tired of the lack of response
to pretty much every bug I raised and switched to debian.