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From: Junio C Hamano <gitster@pobox.com>
To: Rafael Silva <rafaeloliveira.cs@gmail.com>
Cc: git@vger.kernel.org, "Jeff King" <peff@peff.net>,
	"Jonathan Tan" <jonathantanmy@google.com>,
	"SZEDER Gábor" <szeder.dev@gmail.com>
Subject: Re: [PATCH v2 1/1] repack: avoid loosening promisor objects in partial clones
Date: Mon, 19 Apr 2021 16:09:03 -0700	[thread overview]
Message-ID: <xmqqa6pt98j4.fsf@gitster.g> (raw)
In-Reply-To: <20210418135749.27152-2-rafaeloliveira.cs@gmail.com> (Rafael Silva's message of "Sun, 18 Apr 2021 15:57:49 +0200")

Rafael Silva <rafaeloliveira.cs@gmail.com> writes:

> When `git repack -A -d` is run in a partial clone, `pack-objects`
> is invoked twice: once to repack all promisor objects, and once to
> repack all non-promisor objects. The latter `pack-objects` invocation
> is with --exclude-promisor-objects and --unpack-unreachable, which
> loosens all unused objects. Unfortunately, this includes promisor
> objects.
>
> Because the -d argument to `git repack` subsequently deletes all loose
> objects also in packs, these just-loosened promisor objects will be
> immediately deleted. However, this extra disk churn is unnecessary in
> the first place.  For example, a newly-clone partial repo that filters

"in a newly-cloned partial repo", I'd think.

> For testing, we need to validate whether any object was loosened.
> However, the "evidence" (loosened objects) is deleted during the
> process which prevents us from inspecting the object directory.
> Instead, let's teach `pack-objects` to count loosened objects and
> emit via trace2 thus allowing inspecting the debug events after the
> process is finished. This new event is used on the added regression
> test.

Nicely designed.

> +	uint32_t loosened_objects_nr = 0;
>  	struct object_id oid;
>  
>  	for (p = get_all_packs(the_repository); p; p = p->next) {
> @@ -3492,11 +3493,16 @@ static void loosen_unused_packed_objects(void)
>  			nth_packed_object_id(&oid, p, i);
>  			if (!packlist_find(&to_pack, &oid) &&
>  			    !has_sha1_pack_kept_or_nonlocal(&oid) &&
> -			    !loosened_object_can_be_discarded(&oid, p->mtime))
> +			    !loosened_object_can_be_discarded(&oid, p->mtime)) {
>  				if (force_object_loose(&oid, p->mtime))
>  					die(_("unable to force loose object"));
> +				loosened_objects_nr++;
> +			}
>  		}
>  	}
> +
> +	trace2_data_intmax("pack-objects", the_repository,
> +			   "loosen_unused_packed_objects/loosened", loosened_objects_nr);
>  }

OK, so this is just the "stats".

> diff --git a/builtin/repack.c b/builtin/repack.c
> index 2847fdfbab..5f9bc74adc 100644
> --- a/builtin/repack.c
> +++ b/builtin/repack.c
> @@ -20,7 +20,7 @@ static int delta_base_offset = 1;
>  static int pack_kept_objects = -1;
>  static int write_bitmaps = -1;
>  static int use_delta_islands;
> -static char *packdir, *packtmp;
> +static char *packdir, *packtmp_name, *packtmp;
>  
>  static const char *const git_repack_usage[] = {
>  	N_("git repack [<options>]"),
> @@ -530,7 +530,8 @@ int cmd_repack(int argc, const char **argv, const char *prefix)
>  	}
>  
>  	packdir = mkpathdup("%s/pack", get_object_directory());
> -	packtmp = mkpathdup("%s/.tmp-%d-pack", packdir, (int)getpid());
> +	packtmp_name = xstrfmt(".tmp-%d-pack", (int)getpid());
> +	packtmp = mkpathdup("%s/%s", packdir, packtmp_name);

Just a mental note, but we should move away from ".tmp-$$" that is a
remnant from the days back when this was a shell script, and use the
tempfile.h API (#leftoverbits).  Such a change must not be part of
this topic, of course.

Thanks.  Will queue and see what others say.


  parent reply	other threads:[~2021-04-19 23:09 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-03  9:04 rather slow 'git repack' in 'blob:none' partial clones SZEDER Gábor
2021-04-05  1:02 ` Rafael Silva
2021-04-07 21:17   ` Jeff King
2021-04-08  0:02     ` Jonathan Tan
2021-04-08  0:35       ` Jeff King
2021-04-12  7:09     ` Rafael Silva
2021-04-12 21:36     ` SZEDER Gábor
2021-04-12 21:49       ` Bryan Turner
2021-04-12 23:51         ` Jeff King
2021-04-12 23:47       ` Jeff King
2021-04-13  7:12         ` [PATCH 0/3] low-hanging performance fruit with promisor packs Jeff King
2021-04-13  7:15           ` [PATCH 1/3] is_promisor_object(): free tree buffer after parsing Jeff King
2021-04-13 20:17             ` Junio C Hamano
2021-04-14  5:18               ` Jeff King
2021-04-13  7:16           ` [PATCH 2/3] lookup_unknown_object(): take a repository argument Jeff King
2021-04-13  7:17           ` [PATCH 3/3] revision: avoid parsing with --exclude-promisor-objects Jeff King
2021-04-13 20:22             ` Junio C Hamano
2021-04-13 18:10           ` [PATCH 0/3] low-hanging performance fruit with promisor packs SZEDER Gábor
2021-04-14 17:14           ` Jonathan Tan
2021-04-14 19:22           ` Rafael Silva
2021-04-13 18:05         ` rather slow 'git repack' in 'blob:none' partial clones SZEDER Gábor
2021-04-14  5:14           ` Jeff King
2021-04-11 10:59   ` SZEDER Gábor
2021-04-12  7:53     ` Rafael Silva
2021-04-14 19:14 ` [PATCH 0/2] prevent `repack` to unpack and delete promisor objects Rafael Silva
2021-04-14 19:14   ` [PATCH 1/2] repack: teach --no-prune-packed to skip `git prune-packed` Rafael Silva
2021-04-14 23:50     ` Jonathan Tan
2021-04-18 14:15       ` Rafael Silva
2021-04-14 19:14   ` [PATCH 2/2] repack: avoid loosening promisor pack objects in partial clones Rafael Silva
2021-04-15  1:04     ` Jonathan Tan
2021-04-15  3:51       ` Junio C Hamano
2021-04-15  9:03         ` Jeff King
2021-04-15  9:05       ` Jeff King
2021-04-18  7:12       ` Rafael Silva
2021-04-15 18:06     ` Junio C Hamano
2021-04-18  8:40       ` Rafael Silva
2021-04-14 22:10   ` [PATCH 0/2] prevent `repack` to unpack and delete promisor objects Junio C Hamano
2021-04-15  9:15   ` Jeff King
2021-04-18  8:20     ` Rafael Silva
2021-04-18 13:57   ` [PATCH v2 0/1] " Rafael Silva
2021-04-18 13:57     ` [PATCH v2 1/1] repack: avoid loosening promisor objects in partial clones Rafael Silva
2021-04-19 19:15       ` Jonathan Tan
2021-04-21 18:54         ` Rafael Silva
2021-04-19 23:09       ` Junio C Hamano [this message]
2021-04-21 19:25         ` Rafael Silva
2021-04-21 19:32     ` [PATCH v3] " Rafael Silva

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