[Rpm-metadata] Implementing delta metadata

Michael Schroeder mls at suse.de
Wed Nov 30 11:03:47 UTC 2011

On Mon, Sep 26, 2011 at 03:33:54AM +0530, Tirtha Chatterjee wrote:
> I frequently face this problem with yum where i need to install a
> package, and it starts updating all the repo data at once. Since I am
> mostly behind a slow internet connection, this is all the more
> frustrating. I read up http://yum.baseurl.org/wiki/YumFuture , and it
> says here that there are plans to serve metadata delta to reduce the
> download. Also, the large databases can be intelligently broken up
> into smaller pieces (easier to download), so that when i try to
> install a package starting with 'a', only the repodata for all the
> packages starting with 'a' gets downloaded and synced [this was a
> crude example, but conveys the idea].

Uh, that won't work, as the package you want to install may require
something a different package provides.

> I am willing to work on both of these features. I have read the source
> code of createrepo and yum roughly, and am confident I'll be able to
> make this happen. I'd be glad if someone with ample experience in the
> codebase steps forward to guide me.

openSUSE uses a zsync algorithm to download only the "changed" parts
of the repodata. (The repodata needs to be compressed with
--rsyncable in that case, of course).

I don't know if this is what you're aiming for, but createrepo
could be changed to also create the needed .zsync files. (For
openSUSE, the files aren't needed as the data is provided in
the metalink files download.opensuse.org offers.)


Michael Schroeder                                   mls at suse.de
SUSE LINUX Products GmbH,  GF Jeff Hawn, HRB 16746 AG Nuernberg

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