From: Derrick Stolee <stolee@gmail.com>
To: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Cc: "Git List" <git@vger.kernel.org>,
"Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>,
"SZEDER Gábor" <szeder.dev@gmail.com>,
"Jeff King" <peff@peff.net>, "Stefan Beller" <sbeller@google.com>
Subject: Re: [RFC PATCH] We should add a "git gc --auto" after "git clone" due to commit graph
Date: Fri, 5 Oct 2018 08:05:55 -0400 [thread overview]
Message-ID: <dcb8f115-ce3c-64fa-50cc-dd03569c0164@gmail.com> (raw)
In-Reply-To: <87in2hgzin.fsf@evledraar.gmail.com>
On 10/4/2018 5:42 PM, Ævar Arnfjörð Bjarmason wrote:
> I don't have time to polish this up for submission now, but here's a WIP
> patch that implements this, highlights:
>
> * There's a gc.clone.autoDetach=false default setting which overrides
> gc.autoDetach if 'git gc --auto' is run via git-clone (we just pass a
> --cloning option to indicate this).
I'll repeat that it could make sense to do the same thing on clone _and_
fetch. Perhaps a "--post-fetch" flag would be good here to communicate
that we just downloaded a pack from a remote.
> * A clone of say git.git with gc.writeCommitGraph=true looks like:
>
> [...]
> Receiving objects: 100% (255262/255262), 100.49 MiB | 17.78 MiB/s, done.
> Resolving deltas: 100% (188947/188947), done.
> Computing commit graph generation numbers: 100% (55210/55210), done.
This looks like good UX. Thanks for the progress here!
> * The 'git gc --auto' command also knows to (only) run the commit-graph
> (and space is left for future optimization steps) if general GC isn't
> needed, but we need "optimization":
>
> $ rm .git/objects/info/commit-graph; ~/g/git/git --exec-path=$PWD -c gc.writeCommitGraph=true -c gc.autoDetach=false gc --auto;
> Annotating commits in commit graph: 341229, done.
> Computing commit graph generation numbers: 100% (165969/165969), done.
> $
Will this also trigger a full commit-graph rewrite on every 'git commit'
command? Or is there some way we can compute the staleness of the
commit-graph in order to only update if we get too far ahead?
Previously, this was solved by relying on the auto-GC threshold.
> * The patch to gc.c looks less scary with -w, most of it is indenting
> the existing pack-refs etc. with a "!auto_gc || should_gc" condition.
>
> * I added a commit_graph_exists() exists function and only care if I
> get ENOENT for the purposes of this gc mode. This would need to be
> tweaked for the incremental mode Derrick talks about, but if we just
> set "should_optimize" that'll also work as far as gc --auto is
> concerned (e.g. on fetch, am etc.)
The incremental mode would operate the same as split-index, which means
we will still look for .git/objects/info/commit-graph. That file may
point us to more files.
> +int commit_graph_exists(const char *graph_file)
> +{
> + struct stat st;
> + if (stat(graph_file, &st)) {
> + if (errno == ENOENT)
> + return 0;
> + else
> + return -1;
> + }
> + return 1;
> +}
> +
This method serves a very similar purpose to
generation_numbers_enabled(), except your method only cares about the
file existing. It ignores information like `core.commitGraph`, which
should keep us from doing anything with the commit-graph file if false.
Nothing about your method is specific to the commit-graph file, since
you provide a filename as a parameter. It could easily be "int
file_exists(const char *filename)".
Thanks,
-Stolee
next prev parent reply other threads:[~2018-10-05 12:06 UTC|newest]
Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-03 13:23 We should add a "git gc --auto" after "git clone" due to commit graph Ævar Arnfjörð Bjarmason
2018-10-03 13:36 ` SZEDER Gábor
2018-10-03 13:42 ` Derrick Stolee
2018-10-03 14:18 ` Ævar Arnfjörð Bjarmason
2018-10-03 14:01 ` Ævar Arnfjörð Bjarmason
2018-10-03 14:17 ` SZEDER Gábor
2018-10-03 14:22 ` Ævar Arnfjörð Bjarmason
2018-10-03 14:53 ` SZEDER Gábor
2018-10-03 15:19 ` Ævar Arnfjörð Bjarmason
2018-10-03 16:59 ` SZEDER Gábor
2018-10-05 6:09 ` Junio C Hamano
2018-10-10 22:07 ` SZEDER Gábor
2018-10-10 23:01 ` Ævar Arnfjörð Bjarmason
2018-10-03 19:08 ` Stefan Beller
2018-10-03 19:21 ` Jeff King
2018-10-03 20:35 ` Ævar Arnfjörð Bjarmason
2018-10-03 17:47 ` Stefan Beller
2018-10-03 18:47 ` Ævar Arnfjörð Bjarmason
2018-10-03 18:51 ` Jeff King
2018-10-03 18:59 ` Derrick Stolee
2018-10-03 19:18 ` Jeff King
2018-10-08 16:41 ` SZEDER Gábor
2018-10-08 16:57 ` Derrick Stolee
2018-10-08 18:10 ` SZEDER Gábor
2018-10-08 18:29 ` Derrick Stolee
2018-10-09 3:08 ` Jeff King
2018-10-09 13:48 ` Bloom Filters (was Re: We should add a "git gc --auto" after "git clone" due to commit graph) Derrick Stolee
2018-10-09 18:45 ` Ævar Arnfjörð Bjarmason
2018-10-09 18:46 ` Jeff King
2018-10-09 19:03 ` Derrick Stolee
2018-10-09 21:14 ` Jeff King
2018-10-09 23:12 ` Bloom Filters Jeff King
2018-10-09 23:13 ` [PoC -- do not apply 1/3] initial tree-bitmap proof of concept Jeff King
2018-10-09 23:14 ` [PoC -- do not apply 2/3] test-tree-bitmap: add "dump" mode Jeff King
2018-10-10 0:48 ` Junio C Hamano
2018-10-11 3:13 ` Jeff King
2018-10-09 23:14 ` [PoC -- do not apply 3/3] test-tree-bitmap: replace ewah with custom rle encoding Jeff King
2018-10-10 0:58 ` Junio C Hamano
2018-10-11 3:20 ` Jeff King
2018-10-11 12:33 ` Bloom Filters Derrick Stolee
2018-10-11 13:43 ` Jeff King
2018-10-09 21:30 ` We should add a "git gc --auto" after "git clone" due to commit graph SZEDER Gábor
2018-10-09 19:34 ` [PATCH 0/4] Bloom filter experiment SZEDER Gábor
2018-10-09 19:34 ` [PATCH 1/4] Add a (very) barebones Bloom filter implementation SZEDER Gábor
2018-10-09 19:34 ` [PATCH 2/4] commit-graph: write a Bloom filter containing changed paths for each commit SZEDER Gábor
2018-10-09 21:06 ` Jeff King
2018-10-09 21:37 ` SZEDER Gábor
2018-10-09 19:34 ` [PATCH 3/4] revision.c: use the Bloom filter to speed up path-limited revision walks SZEDER Gábor
2018-10-09 19:34 ` [PATCH 4/4] revision.c: add GIT_TRACE_BLOOM_FILTER for a bit of statistics SZEDER Gábor
2018-10-09 19:47 ` [PATCH 0/4] Bloom filter experiment Derrick Stolee
2018-10-11 1:21 ` [PATCH 0/2] Per-commit filter proof of concept Jonathan Tan
2018-10-11 1:21 ` [PATCH 1/2] One filter per commit Jonathan Tan
2018-10-11 12:49 ` Derrick Stolee
2018-10-11 19:11 ` [PATCH] Per-commit and per-parent filters for 2 parents Jonathan Tan
2018-10-11 1:21 ` [PATCH 2/2] Only make bloom filter for first parent Jonathan Tan
2018-10-11 7:37 ` [PATCH 0/2] Per-commit filter proof of concept Ævar Arnfjörð Bjarmason
2018-10-15 14:39 ` [PATCH 0/4] Bloom filter experiment Derrick Stolee
2018-10-16 4:45 ` Junio C Hamano
2018-10-16 11:13 ` Derrick Stolee
2018-10-16 12:57 ` Ævar Arnfjörð Bjarmason
2018-10-16 13:03 ` Derrick Stolee
2018-10-18 2:00 ` Junio C Hamano
2018-10-16 23:41 ` Jonathan Tan
2018-10-08 23:02 ` We should add a "git gc --auto" after "git clone" due to commit graph Junio C Hamano
2018-10-03 14:32 ` Duy Nguyen
2018-10-03 16:45 ` Duy Nguyen
2018-10-04 21:42 ` [RFC PATCH] " Ævar Arnfjörð Bjarmason
2018-10-05 12:05 ` Derrick Stolee [this message]
2018-10-05 13:05 ` Ævar Arnfjörð Bjarmason
2018-10-05 13:45 ` Derrick Stolee
2018-10-05 14:04 ` Ævar Arnfjörð Bjarmason
2018-10-05 19:21 ` Jeff King
2018-10-05 19:41 ` Derrick Stolee
2018-10-05 19:47 ` Jeff King
2018-10-05 20:00 ` Derrick Stolee
2018-10-05 20:02 ` Jeff King
2018-10-05 20:01 ` Ævar Arnfjörð Bjarmason
2018-10-05 20:09 ` Jeff King
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