Re: Packages file missing from unstable archive

[Michael Vogt <mvo@debian.org>]

On Thu, Oct 27, 2005 at 10:06:22AM +0200, Robert Lemmen wrote:
> On Wed, Oct 26, 2005 at 09:15:38PM -0400, Joey Hess wrote:
> > (And yes, we still need a solution to speed up the actual deb file
> > downloads..)
[..]
> if zsync would be taught to handle .deb files as it does .gz files, and
> a method for apt be written, how big are the chances that support could 
> be integrated into dak? the effort wouldn't be *that* big...

I did a pretty unscientific test with apt and the changes from 
0.6.41 -> 0.6.42.1. It contains a good mix of code changes,
documentation updates and translation updates [1].

With the two normals debs I got no effect at all because no usable
data was found. 

I then repacked the data.tar.gz and control.tar.gz inside the deb with
"--rsyncable" (and reassmbled the deb).  This resulted in:
"Read apt_0.6.41_i386.deb. Target 0.8% complete."
So this didn't had a lot of effect either. 

My next test was to use only the data.tar.gz of the two
archives. Zsync will extract the gzip file then and use the tar as the
base. With that I got:
--------------------8<------------------------
Read data.tar.gz. Target 34.1% complete.
used 1056768 local, fetched 938415
--------------------8<------------------------
The size of the data.tar.gz is 1210514. 

A problem is that zsync needs to teached to deal with deb files (that
is, that it needs to unpack the data.tar and use that for the syncs).

Having it inside dak is not (at the beging) a requirement. Zsync seems
to be able to deal with URLs, so we could create a pool with zsync
files on any server and let them point to ftp.debian.org.

We need to guarantee that the md5sum of the synced deb must match the
md5sum in the Packages file. Initial tests indicate that that is not
the case. Only the md5sum of the unpacked data.tar file matches, not
from the gzip file (or the deb). This is a serious showstoper IMHO. 


Cheers,
 Michael

[1] I would love to hear results from other people testing it with
different packages and different changes.
-- 
Linux is not The Answer. Yes is the answer. Linux is The Question. - Neo