From: Johan Herland <johan@herland.net>
To: Theodore Tso <tytso@mit.edu>
Cc: git@vger.kernel.org, Jeff King <peff@peff.net>,
Will Palmer <wmpalmer@gmail.com>,
Avery Pennarun <apenwarr@gmail.com>
Subject: Re: Why is "git tag --contains" so slow?
Date: Thu, 8 Jul 2010 16:35:25 +0200 [thread overview]
Message-ID: <201007081635.25381.johan@herland.net> (raw)
In-Reply-To: <11D5771D-EB47-42E9-BCC3-69C8FE1999EC@MIT.EDU>
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On Thursday 08 July 2010, Theodore Tso wrote:
> On Jul 7, 2010, at 1:45 PM, Jeff King wrote:
> > And of course it's just complex, and I tend to shy away from
> > complexity when I can. The question to me comes back to (1)
> > above. Is massive clock skew a breakage that should produce a few
> > incorrect results, or is it something we should always handle?
>
> Going back to the question that kicked off this thread, I wonder if
> there is some way that cacheing could be used to speed up the all
> cases, or at lest the edge cases, without imposing as much latency as
> tracking the max skew? i.e., some thing like gitk's gitk.cache
> file. For bonus points, it could be a cache file that is used by
> both gitk and git tag --contains, git branch --contains, and git
> name-rev.
>
> Does that sound like reasonable idea?
Here's a quick-and-dirty POC which builds a mapping from commits to
their children and stores it using git notes [1], and then uses that to
implement 'git tag --contains <commit>' by traversing _forwards_ from
<commit> and printing all tags we encounter along the way [2].
[1]: The attached "build_childnotes.py" script builds this mapping.
Invoke as follows:
git log --all --format="%H,%P" |
./build_childnotes.py |
git fast-import
[2]: The attached "git_tag_contains.py" script traverses the notes
printing out tags along the way. Invoke it as follows:
git_tag_contains.py <commit>
The second script is way too slow, and really needs to use "git
cat-file --batch" to not fork a process for every commit in history...
...Johan
--
Johan Herland, <johan@herland.net>
www.herland.net
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next prev parent reply other threads:[~2010-07-08 14:36 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-01 0:54 Why is "git tag --contains" so slow? Theodore Ts'o
2010-07-01 0:58 ` Shawn O. Pearce
2010-07-03 23:27 ` Sam Vilain
2010-07-01 1:00 ` Avery Pennarun
2010-07-01 12:17 ` tytso
2010-07-01 15:03 ` Jeff King
2010-07-01 15:38 ` Jeff King
2010-07-02 19:26 ` tytso
2010-07-03 8:06 ` Jeff King
2010-07-04 0:55 ` tytso
2010-07-05 12:27 ` Jeff King
2010-07-05 12:33 ` [RFC/PATCH 1/4] tag: speed up --contains calculation Jeff King
2010-10-13 22:07 ` Jonathan Nieder
2010-10-13 22:56 ` Clemens Buchacher
2011-02-23 15:51 ` Ævar Arnfjörð Bjarmason
2011-02-23 16:39 ` Jeff King
2010-07-05 12:34 ` [RFC/PATCH 2/4] limit "contains" traversals based on commit timestamp Jeff King
2010-10-13 23:21 ` Jonathan Nieder
2010-07-05 12:35 ` [RFC/PATCH 3/4] default core.clockskew variable to one day Jeff King
2010-07-05 12:36 ` [RFC/PATCH 4/4] name-rev: respect core.clockskew Jeff King
2010-07-05 12:39 ` Why is "git tag --contains" so slow? Jeff King
2010-10-14 18:59 ` Jonathan Nieder
2010-10-16 14:32 ` Clemens Buchacher
2010-10-27 17:11 ` Jeff King
2010-10-28 8:07 ` Clemens Buchacher
2010-07-05 14:10 ` tytso
2010-07-06 11:58 ` Jeff King
2010-07-06 15:31 ` Will Palmer
2010-07-06 16:53 ` tytso
2010-07-08 11:28 ` Jeff King
2010-07-08 13:21 ` Will Palmer
2010-07-08 13:54 ` tytso
2010-07-07 17:45 ` Jeff King
2010-07-08 10:29 ` Theodore Tso
2010-07-08 11:12 ` Jakub Narebski
2010-07-08 19:29 ` Nicolas Pitre
2010-07-08 19:39 ` Avery Pennarun
2010-07-08 20:13 ` Nicolas Pitre
2010-07-08 21:20 ` Jakub Narebski
2010-07-08 21:30 ` Sverre Rabbelier
2010-07-08 23:10 ` Nicolas Pitre
2010-07-08 23:15 ` Nicolas Pitre
2010-07-08 11:31 ` Jeff King
2010-07-08 14:35 ` Johan Herland [this message]
2010-07-08 19:06 ` Nicolas Pitre
2010-07-07 17:50 ` Jeff King
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