Re: git gc --aggressive led to about 40 times slower "git log --raw"

On Sat, Feb 22, 2014 at 3:53 PM, David Kastrup [off-list ref] wrote:

David Kastrup [off-list ref] writes:

quoted

Duy Nguyen [off-list ref] writes:

quoted

OK with git://git.savannah.gnu.org/emacs.git we have

 - a 209MB pack with --aggressive
 - 1.3GB with --depth=50
 - 1.3GB with --window=4000 --depth=32
 - 1.3GB with --depth=20
 - 821MB with --depth=250 for commits --before=2.years.ago, --depth=50
for the rest

So I don't think we should go with your following patch because the
size explosion is just too much no matter how faster it could be. An
immediate action could be just make --depth=250 configurable and let
people deal with it. A better option is something like "3 repack
steps" you described where we pack deep depth first, mark .keep, pack
shallower depth and combine them all into one.

I'm not really happy with --depth=250 producing 209MB while
--depth=250 --before=2.year.ago a 800MB pack. It looks wrong (or maybe
I did something wrong)

That does look strange: Emacs has a history of more than 30 years.  But
the Git mirror is quite younger.  Maybe one needs to make sure to use
the author date rather than the commit date here?

I think commit date is fine because it covers a large portion of
objects (649946 per total 739990) and it does not (or should not)
affect object ordering in pack-objects/rev-list.

Another thing: did you really use --depth=250 here or did you use
--aggressive?  It may be that the latter also sets other options?

I can't use --aggressive because I need to feed revisions directly to
pack-objects. --aggressive also sets --window=250. Thanks for
checking. My machine will have another workout session.
-- 
Duy