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Re: 1 of 400 dpkg databases corrupt?

On Sat, Aug 23, 2008 at 09:13:42AM +0200, Petter Reinholdtsen wrote:
> [Russ Allbery]
> > It's not *impossible*... someone could be running the scripts from the
> > package without having the package installed.  I don't know why they'd do
> > that, though, or whether that's a more plausible explanation than a
> > corrupt database.
> Sure, it is possible for people to run the script manually without the
> package, but I believe it is unlikely.

I believe .25% of systems having a corrupt dpkg database is also rather
unlikely; it would mean we're getting a far lower amount of bugreports
than we deserve.

> The ratio of hosts submitting to popcon without having popcon
> installed has been fairly stable, and I kind of doubt that such
> activity is done regularly by several people.

Indeed. This would also rule out a temporary bug in popcon (in that
case, it would have been a peak which would subside over time). Instead,
my guess is that there are corner-case situations in which popcon tries
to read the dpkg database at a time when it is in a state of flux; and
that because of that, popcon doesn't get all the existing data, only
part of it.

Of the top of my head, I can think of two possible examples where this
might be the case:
- If popcon tries to read the dpkg database while it's being installed
  or immediately after (no clue whether it does), that could be the
  problem. This would suggest that the ratio of the number of people
  newly installing popcon versus the number of people having popcon
  installed already is stable over time; this in turn would suggest an
  increasing rate of growth.
- Another possibility might be a group of people having popcon and
  something like cron-apt installed at the same time; if both cronjobs
  trigger at approximately the same time, that would greatly increase
  the chance that popcon is indeed trying to read the dpkg database at
  the time when cron-apt is rewriting it.

I think the latter of the above two is the more likely. Of course, all
of the above is guesswork...

<Lo-lan-do> Home is where you have to wash the dishes.
  -- #debian-devel, Freenode, 2004-09-22

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