Public SourceMage Discussion List

[flux <flux AT sourcemage.org>]

Sukneet Basuta (sukneet AT gmail.com) wrote [11.11.13 13:07]:
> On Sat, Nov 12, 2011 at 8:02 PM, flux <flux AT sourcemage.org> wrote:
> > It's necessary for stable sorcery to support xz, otherwise you'd be
> > forcing all users to switch to either test or devel sorcery. If they
> > don't switch and there are xz things in the grimoire that stable sorcery
> > can't handle, then those bits in the grimoire will be broken for them.
> 
> Fair enough. But when sorcery 1.15 is pushed to stable, should we be
> using xz over bzip2 or gzip given the option? xz-utils isn't a
> dependency of basesytem, which is why I'm hesitant.
> 
> > Also, xz is not absolutely better than bzip2 or gzip. It depends on the
> > particular material being compressed, as well as what compression levels
> > are being compared for the respective compressors (both for compressed
> > size and time for decompression), AFAIK.
> 
> True, but in most cases, xz has a better compression ratio and
> decompression time. Upstream developers are going to (or at least
> should) use a compression level that makes xz advantages over bzip2.
> Why would they provide it as an alternative otherwise?

Where exactly would you replace bzip2 and/or gzip by xz? If for upstream
sources, I think it depends on what upstream is doing. If upstream drops
the others for xz, obviously we'd do that. If they're just providing an
additional download option, that doesn't necessetate that we switch
anything on our end (though it also doesn't prevent us from doing it). I
think really it will come down to a matter of personal choice. The same
used to be the case between gzip and bzip2. xz is just a new player to
the game, and there's no clear absolute winner that will make literally
everyone happy. Don't forget, there are yet other (at least
semi-)popular choices as well (such as lzo).

I'm not against xz personally (though compressing with it does seem to
take considerably longer, so that would be a factor when creating, say,
install logs), but I know that I don't speak for everyone, and no one
really does. As long as we have choice, I think it can work out nicely.

Perhaps we can eventually add support to configure sorcery to "prefer" a
certain package option (.gz, .xz, etc.) depending on what's available in
a spell (this would require changing spells a little bit too perhaps),
and if a certain option isn't available it can go with the next
preference down in the list. Just an idea, probably a royal pain to
implement, and possibly not for much gain, but now it's out there. :)

-- 
Justin "flux_control" Boffemmyer
Cauldron wizard and general mage
Source Mage GNU/Linux
http://www.sourcemage.org

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