Re: PostgreSQL GIT mirror status

On Thu, Jan 15, 2009 at 2:26 AM, Peter Eisentraut <peter_e@gmx.net> wrote:
> git gc --aggressive has now been run...

I did a little bit more investigation. Actually, it seems that
--aggressive settings aren't 'fixed', but seems okay for Postgres...

To avoid spreading misconception, I figured I should post this for
completeness:

I think --aggressive it runs something akin to "git repack -a -f -d
--window=100 --depth=100" by default, (tweakable using configuration
options, I think). In fact, repacking the emacs git repository with
--aggressive causes the pack to explode in size. My guess is that some
projects would benefit from larger window sizes (although repacking
then takes longer and is more computationally expensive). Too-long
delta chains can degrade performance, so some care must be exhibited
with --depth.

I have tried with the settings "git repack -a -f -d --window=250
--depth=250" as suggested in the mail by Linus Torvalds posted
previously. For the Postgres git it probably shaves off another 10MB,
so it seems the difference is somewhat negligible, as I have tried
much more aggressive settings and have not seen appreciable gain
beyond that (perhaps creeping towards another 10MB savings). It may be
worth doing if you have extra time on your hands.

Also, unless git.postgresql.org is using object alternates/shared
repos, you may want to consider deleting the ./logs/ directory or
expiring them with 'git reflog': there's a lot of garbage objects that
will remain reachable otherwise and will not be collected.

fdr