Re: git tag --contains now takes a long time

From: Junio C Hamano <gitster@pobox.com>
Date: Oct 16, 2015, 22:37 UTC
Message-ID: <xmqqd1wecuea.fsf@gitster.mtv.corp.google.com>
In-Reply-To: <20151016220739.GF17700@cantor.redhat.com>

Jerry Snitselaar <jsnitsel@redhat.com> writes:

> Is this known and being looked into? I've seen a jump from 12 seconds
> to over 9 minutes with running git tag --contains on my kernel repo.

Thanks for a report. Yes, it seems that there is a recent regression on the 'master' branch, not yet in any released version, and we can observe with a much smaller repository X-<. E.g.

    git tag --contains v2.5.0~12

in git itself seems to have got 10 times slower.

Show 57 quoted lines

> snits ~/dev/linux> git --version
> git version 2.6.1.145.gb27dacc
>
> snits ~/dev/linux> time git tag --contains 825fcfc
> next-20151012
> next-20151013
> v4.3-rc5
>
> real	9m4.765s
> user	8m56.157s
> sys	0m2.450s
>
>
>
> snits ~/dev/linux> git --version
> git version 2.5.0.275.gac4cc86
>
> snits ~/dev/linux> time git tag --contains 825fcfc
> next-20151012
> next-20151013
> v4.3-rc5
>
> real	0m12.842s
> user	0m11.536s
> sys	0m1.098s
>
>
>
> b7cc53e92c806b73e14b03f60c17b7c29e52b4a4 is the first bad commit
> commit b7cc53e92c806b73e14b03f60c17b7c29e52b4a4
> Author: Karthik Nayak <karthik.188@gmail.com>
> Date:   Fri Sep 11 20:36:16 2015 +0530
>
>    tag.c: use 'ref-filter' APIs
>
>    Make 'tag.c' use 'ref-filter' APIs for iterating through refs, sorting
>    and printing of refs. This removes most of the code used in 'tag.c'
>    replacing it with calls to the 'ref-filter' library.
>
>    Make 'tag.c' use the 'filter_refs()' function provided by 'ref-filter'
>    to filter out tags based on the options set.
>
>    For printing tags we use 'show_ref_array_item()' function provided by
>    'ref-filter'.
>
>    We improve the sorting option provided by 'tag.c' by using the sorting
>    options provided by 'ref-filter'. This causes the test 'invalid sort
>    parameter on command line' in t7004 to fail, as 'ref-filter' throws an
>    error for all sorting fields which are incorrect. The test is changed
>    to reflect the same.
>
>    Modify documentation for the same.
>
>    Mentored-by: Christian Couder <christian.couder@gmail.com>
>    Mentored-by: Matthieu Moy <matthieu.moy@grenoble-inp.fr>
>    Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
>    Signed-off-by: Junio C Hamano <gitster@pobox.com>