From: "Alex Bennée" <kernel-hacker@bennee.com>
To: Thomas Rast <trast@inf.ethz.ch>
Cc: John Keeping <john@keeping.me.uk>,
Ramkumar Ramachandra <artagnon@gmail.com>,
Git Mailing List <git@vger.kernel.org>
Subject: Re: Poor performance of git describe in big repos
Date: Fri, 31 May 2013 09:40:01 +0100 [thread overview]
Message-ID: <CAJ-05NOdg5TvjzEMrXaPgogU5z5W6kywZhD-82eTUmvE9Hp=Lw@mail.gmail.com> (raw)
In-Reply-To: <87obbr5zg3.fsf@linux-k42r.v.cablecom.net>
On 31 May 2013 09:24, Thomas Rast <trast@inf.ethz.ch> wrote:
> Alex Bennée <kernel-hacker@bennee.com> writes:
>> On 30 May 2013 20:30, John Keeping <john@keeping.me.uk> wrote:
>>> On Thu, May 30, 2013 at 06:21:55PM +0200, Thomas Rast wrote:
>>>> Alex Bennée <kernel-hacker@bennee.com> writes:
>>>> > On 30 May 2013 16:33, Thomas Rast <trast@inf.ethz.ch> wrote:
> <snip>
>>>> No, my theory is that you tagged *the blobs*. Git supports this.
>>
>> Wait is this the difference between annotated and non-annotated tags?
>> I thought a non-annotated just acted like references to a particular
>> tree state?
>
> A tag is just a ref. It can point at anything, in particular also a
> blob (= some file *contents*).
>
> An annotated tag is just a tag pointing at a "tag object". A tag object
> contains tagger name/email/date, a reference to an object, and a tag
> message.
>
> The slowness I found relates to having tags that point at blobs directly
> (unannotated).
I think you are right. I was brave (well I assumed the tags would come
back from the upstream repo) and ran:
git for-each-ref | grep "refs/tags" | grep "commit" | cut -d '/' -f 3
| xargs git tag -d
And boom:
09:19 ajb@sloy/x86_64 [work.git] >time /usr/bin/git --no-pager
describe --long --tags
ajb-build-test-5225-2-gdc0b771
real 0m0.009s
user 0m0.008s
sys 0m0.000s
Which is much better performance. So it does look like unannotated
tags pointing at binary blobs is the failure case.
<snip>
>
> I would be more interested in this:
>
> git for-each-ref | grep ' blob'
Hmmm that gives nothing. All the refs are either tag or commit
> and
>
> (git for-each-ref | grep ' blob' | cut -d\ -f1 | xargs -n1 git
>cat-file blob) | wc -c
However I have some big commits it seems:
09:37 ajb@sloy/x86_64 [work.git] >(git for-each-ref | grep ' commit' |
cut -d\ -f1 | xargs -n1 git cat-file commit) | wc -c
1147231984
>
> The first tells you if you have any refs pointing at blobs. The second
> computes their total unpacked size. My theory is that the second yields
> some large number (hundreds of megabytes at least).
>
> It would be nice if you checked, because if there turn out to be big
> blobs, we have all the pieces and just need to assemble the best
> solution. Otherwise, there's something else going on and the problem
> remains open.
If you want any other numbers I'm only too happy to help. Sorry I
can't share the repo though...
--
Alex, homepage: http://www.bennee.com/~alex/
next prev parent reply other threads:[~2013-05-31 8:40 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-30 10:38 Poor performance of git describe in big repos Alex Bennée
2013-05-30 11:33 ` Ramkumar Ramachandra
2013-05-30 13:09 ` Alex Bennée
2013-05-30 14:32 ` Ramkumar Ramachandra
2013-05-30 15:01 ` Alex Bennée
2013-05-30 15:17 ` Ramkumar Ramachandra
2013-05-30 15:33 ` Thomas Rast
2013-05-30 16:01 ` Alex Bennée
2013-05-30 16:21 ` Thomas Rast
2013-05-30 16:44 ` Thomas Rast
2013-05-30 19:01 ` Antoine Pelisse
2013-05-30 20:00 ` [PATCH 1/2] sha1_file: silence sha1_loose_object_info Thomas Rast
2013-05-30 20:00 ` [PATCH 2/2] lookup_commit_reference_gently: do not read non-{tag,commit} Thomas Rast
2013-05-30 21:22 ` Jeff King
2013-05-31 0:52 ` Duy Nguyen
2013-05-31 8:08 ` Thomas Rast
2013-05-31 16:00 ` Jeff King
2013-05-31 6:43 ` Ramkumar Ramachandra
2013-05-31 8:16 ` Thomas Rast
2013-05-30 19:30 ` Poor performance of git describe in big repos John Keeping
2013-05-31 8:14 ` Alex Bennée
2013-05-31 8:24 ` Thomas Rast
2013-05-31 8:40 ` Alex Bennée [this message]
2013-05-31 8:46 ` Thomas Rast
2013-05-31 9:57 ` Alex Bennée
2013-06-03 8:02 ` Alex Bennée
2013-06-03 16:32 ` Junio C Hamano
2013-06-03 17:48 ` Junio C Hamano
2013-05-31 10:27 ` Thomas Rast
2013-05-31 16:17 ` Jeff King
2013-06-03 8:39 ` Alex Bennée
2013-06-03 14:49 ` Jeff King
2013-05-31 8:32 ` John Keeping
2013-05-31 8:49 ` Alex Bennée
2013-05-31 8:59 ` John Keeping
2013-05-30 11:48 ` John Keeping
2013-05-30 12:29 ` Alex Bennée
2013-05-30 13:20 ` Duy Nguyen
[not found] ` <CAJ-05NPacjAEC99Ntd9eMnTD9_PMMYFob-_tAx5CeSB79TkRSg@mail.gmail.com>
2013-05-30 13:45 ` Duy Nguyen
2013-05-30 14:02 ` Alex Bennée
2013-05-30 13:16 ` Alex Bennée
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