[Aptitude-devel] Bug#697724: Bug#697724: aptitude: selecting packages in the curses interface slow iff Acquire::GzipIndexes="true"

[Axel Beckert]

Hi Daniel,

Daniel Hartwig wrote:
> On 9 January 2013 05:55, Axel Beckert <abe at debian.org> wrote:
> > If I set Acquire::GzipIndexes to "true" in apt.conf, remove all files
> > from /var/lib/apt/lists/ and run "apt-get update" again, the downloaded
> > files don't get uncompressed but stay in compressed form on disk.
> 
> These indices (Packages files mainly) are part of APTs database and
> contain much information that is not present in the binary cache.  While
> apt-get performs fine with this setting, aptitude frequently accesses
> package fields that are not in the binary cache and wants for
> uncompressed access to the indices.

I see.

> > I though don't expect that this causes the obvious speed difference
> > between with and without Acquire::GzipIndexes, so I suspect it's some
> > decompression which slows down selecting packages in the TUI.
> >
> > So maybe it can cache the information gathered at the first time read or
> > read all the information into memory on startup (which would likely
> > raise memory consumption which would be not ideal either).
> 
> I believe that synaptic does something like this as part of converting
> the data to a form suitable for GTK+ to use.  However, implementing
> such caching above the APT level is a major burden from a maintenance
> perspective.

Indeed, also because other tools have way worse issues with that
setting, e.g. http://bugs.debian.org/617856

> Better to do this in APT, [...]

*nod* Reassigning, affects aptitude and downgrading to wishlist?

> Given the ease of configuring this setting appropriately I doubt
> anyone will be interested in implementing “on-demand” caching of
> the uncompressed data.

*nod*

> This setting is really for situations where programs such as
> aptitude are not used, and the extra MBs of disk space are
> important.

Here I disagree. These things are not mutually exclusive. If there
wasn't #617856, I may have reported this much earlier (*), because on
my EeePC with just 4 GB of hard-wired disk space, I'd be very happy
about that 87 MB more disk space I'd have if I could use that feature.

There are also a few boxes which run on CF cards with 512 MB to 2 GB
where I'm happy about every MB I can spare without compensating in
features.

(*) I mostly reported it because
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=317841#10 looks a lot
like this and I didn't want to close #317841 (which was definitely a
different issue) without giving that commenter's issue a proper bug
report.

		Regards, Axel
-- 
 ,''`.  |  Axel Beckert <abe at debian.org>, http://people.debian.org/~abe/
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