[Rpm-metadata] adding different compression types to createrepo

[James Antill]

On Tue, 2010-08-03 at 18:12 +0200, Anders F Björklund wrote:
> James Antill wrote:
> 
> > On Tue, 2010-08-03 at 11:14 -0400, seth vidal wrote:
> >
> >>> I think the extended opensuse patch should be acceptable, where it
> >>> uses "primary" for .xml or .xml.gz and the new "primary_lzma" key
> >>> for .xml.lzma or .xml.xz - plus the same added for "filelists_lzma"
> >>> and "other_lzma", it causes less breakage than changing "primary"...
> >>
> >> I suspect it would make sense to provide:
> >>
> >> [primary|filelists|other][_db]_xz in the repomd.xml, in addition  
> >> to the
> >> gzip/bzip2 compressed alternatives and then gradually phase out the
> >> older ones.
> 
> openSUSE actually uses LZMA, not XZ. Both for RPMS and for repodata.
>
> Using liblzma would handle both, but feeding xz to lzma doesn't work.

 Does that matter? The rpm payload is inside rpm, so matters less, and
can't be changed now anyway. But for "normal" files the convention is to
use .xz now ... no?

> >  *shrug*, I'm not sure why we'd want to add support for lzma on the
> > obsolete .xml files. Smart and apt both support .sqlite now, and if
> > zypper doesn't they can always use modifyrepo to add them for SuSE.
> 
> Smart supposes .sqlite, but it is slower to parse and not extendible ?

 I find it _really_ hard to believe that XML parsing is faster than
reading data from .sqlite.
 .sqlite is about as extensible as XML, and primary/etc. have never
changed (and the coming changes are just as likely to be done by adding
new files).

 However there is a cost to having 4-8 different versions of
primary/filelists/etc. ... both in createrepo time, in hosting disk
space, in maintenance of all the weird code paths and in repomd.xml size
(most repos. aren't using metalink, so repomd.xml is downloaded a lot).

> >  Also calling them "primary_db.xz" would fit the convention with
> > "groups.gz".
> 
> Except that it is "group_gz"... (the type of the comps.xml.gz file)

 You're right, for some reason I thought it was "group.gz" ... my bad,
ignore that comment.