From: John Keeping <john@keeping.me.uk>
To: "Alex Bennée" <kernel-hacker@bennee.com>
Cc: Thomas Rast <trast@inf.ethz.ch>,
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 09:32:52 +0100 [thread overview]
Message-ID: <20130531083252.GA1072@serenity.lan> (raw)
In-Reply-To: <CAJ-05NOEuxOVy7LFp_XRa_08G-Mj0x7q+RiR=u71-iyfOXpHow@mail.gmail.com>
On Fri, May 31, 2013 at 09:14:49AM +0100, Alex Bennée wrote:
> 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:
> >> >> Alex Bennée <kernel-hacker@bennee.com> writes:
> > <snip>
> >> > Will it be loading the blob for every commit it traverses or just ones that hit
> >> > a tag? Why does it need to load the blob at all? Surely the commit
> >> > tree state doesn't
> >> > need to be walked down?
> >>
> >> 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?
No, this is something slightly different. In Git there are four types
of object: tag, commit, tree and blob. When you have a heavyweight tag,
the tag reference points at a tag object (which in turn points at
another object). With a lightweight tag, the tag reference typically
points at a commit object.
However, there is no restriction that says that a tag object must point
to a commit or that a lightweight tag must point at a commit - it is
equally possible to point directly at a tree or a blob (although a lot
less common).
Thomas is suggesting that you might have a tag that does not point at a
commit but instead points to a blob object.
> > You can see if that is the case by doing something like this:
> >
> > eval $(git for-each-ref --shell --format '
> > test $(git cat-file -t %(objectname)^{}) = commit ||
> > echo %(refname);')
> >
> > That will print out the name of any ref that doesn't point at a
> > commit.
>
> Hmm that didn't seem to work.
You mean there was no output? In that case it's likely that all your
references do indeed point at commits.
> But looking at the output by hand I
> certainly have a mix of tags that are commits vs tags:
>
>
> 09:08 ajb@sloy/x86_64 [work.git] >git for-each-ref | grep "refs/tags"
> | grep "commit" | wc -l
> 1345
> 09:12 ajb@sloy/x86_64 [work.git] >git for-each-ref | grep "refs/tags"
> | grep -v "commit" | wc -l
> 66
This means that you have 1345 lightweight tags and 66 heavyweight tags,
assuming that all of the lines that don't say "commit" do say "tag".
By the way, I don't remember if you said which version of Git you're
using. If it's an older version then it's possible that something has
changed.
next prev parent reply other threads:[~2013-05-31 8:33 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
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 [this message]
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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