From: Junio C Hamano <gitster@pobox•com>
To: "Jens Lindström" <jl@opera•com>
Cc: git@vger•kernel.org
Subject: Re: [PATCH v2 2/3] remote: repack packed-refs once when deleting multiple refs
Date: Fri, 23 May 2014 12:11:57 -0700 [thread overview]
Message-ID: <xmqq61kwjon6.fsf@gitster.dls.corp.google.com> (raw)
In-Reply-To: <537F2319.7040105@opera.com> ("Jens Lindström"'s message of "Fri, 23 May 2014 12:29:45 +0200")
Jens Lindström <jl@opera•com> writes:
> When 'git remote rm' or 'git remote prune' were used in a repository
> with many refs, and needed to delete many remote-tracking refs, a lot
> of time was spent deleting those refs since for each deleted ref,
> repack_without_refs() was called to rewrite packed-refs without just
> that deleted ref.
>
> To avoid this, call repack_without_refs() first to repack without all
> the refs that will be deleted, before calling delete_ref() to delete
> each one completely. The call to repack_without_ref() in delete_ref()
> then becomes a no-op, since packed-refs already won't contain any of
> the deleted refs.
>
> Signed-off-by: Jens Lindström <jl@opera•com>
> ---
> Note: remove_branches() no longer checks that the remote-tracking
> branches it deletes point at the right object before deleting them
> by passing the expected SHA-1 to delete_ref(). This was a required
> change since all packed refs have been deleted already by the time
> we call delete_ref(), which causes delete_ref() to fail if given an
> expected SHA-1 to check. 'remote prune' already behaved this way.
>
> builtin/remote.c | 20 ++++++++++++++++++--
> refs.c | 2 +-
> refs.h | 2 ++
> 3 files changed, 21 insertions(+), 3 deletions(-)
>
> diff --git a/builtin/remote.c b/builtin/remote.c
> index 84802cd..d33abe6 100644
> --- a/builtin/remote.c
> +++ b/builtin/remote.c
> @@ -749,15 +749,23 @@ static int mv(int argc, const char **argv)
>
> static int remove_branches(struct string_list *branches)
> {
> + const char **branch_names;
> int i, result = 0;
> +
> + branch_names = xmalloc(branches->nr * sizeof(*branch_names));
> + for (i = 0; i < branches->nr; i++)
> + branch_names[i] = branches->items[i].string;
> + result |= repack_without_refs(branch_names, branches->nr);
> + free(branch_names);
Hmph. I wonder if you can refactor/enhance the interface to the
repack_without_refs() function before this step in the series, so
that the function lets the caller to know if each ref was actually
removed or it was not in packed-refs from the beginning, and also I
wonder if such a refactoring helps. My gut feeling is that it would
not help that much this particular series, but it would probably be
a good thing to do in the longer run. So probably it is better to do
without such a change as a part of this series.
> for (i = 0; i < branches->nr; i++) {
> struct string_list_item *item = branches->items + i;
> const char *refname = item->string;
> - unsigned char *sha1 = item->util;
Here, you can check if the refname still exists as a ref; if it no
longer exists, it would mean that the only copy of the ref was in
the packed-refs file and you have already deleted it, and you can
refrain from calling delete_ref() altogether, e.g.
if (!ref_exists(refname))
continue; /* already removed the sole copy from packed-ref */
and then still retain the safetly against racing somebody else who
created or updated the ref you wanted to remove here by passing the
object name to delete_ref().
> - if (delete_ref(refname, sha1, 0))
> + if (delete_ref(refname, NULL, 0))
> result |= error(_("Could not remove branch %s"), refname);
> }
> +
> return result;
> }
next prev parent reply other threads:[~2014-05-23 19:12 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-20 10:34 [PATCH 0/2] remote: optimize rm/prune ref deletion Jens Lindström
2014-05-20 10:39 ` [PATCH 1/2] remote: defer repacking packed-refs when deleting refs Jens Lindström
2014-05-20 19:30 ` Junio C Hamano
2014-05-20 20:29 ` Junio C Hamano
2014-05-23 10:03 ` Jens Lindström
2014-05-23 17:09 ` Junio C Hamano
2014-05-24 7:54 ` Jens Lindström
2014-05-27 16:55 ` Junio C Hamano
2014-05-20 10:41 ` [PATCH 2/2] remote prune: optimize "dangling symref" check/warning Jens Lindström
2014-05-23 10:26 ` [PATCH v2 0/3] remote: optimize rm/prune ref deletion Jens Lindström
2014-05-23 10:28 ` [PATCH v2 1/3] remote rm: delete remote configuration as the last Jens Lindström
2014-05-23 18:55 ` Junio C Hamano
2014-05-23 10:29 ` [PATCH v2 2/3] remote: repack packed-refs once when deleting multiple refs Jens Lindström
2014-05-23 19:11 ` Junio C Hamano [this message]
2014-05-23 19:25 ` Junio C Hamano
2014-05-23 10:30 ` [PATCH v2 3/3] remote prune: optimize "dangling symref" check/warning Jens Lindström
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