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Re: Git Scaling: What factors most affect Git performance for a large repo?

From
Junio C Hamano <gitster@pobox.com>
Date
Mar 2, 2015, 20:15 UTC
Message-ID
<xmqqsidn9mvo.fsf@gitster.dls.corp.google.com>
In-Reply-To
<CACBZZX7O77zfn75vJXsSyR58UjC_bfTu-DWwJC8n2fhemVBn2w@mail.gmail.com>
Ævar Arnfjörð Bjarmason <avarab@gmail.com> writes:
Show 20 quoted lines
> On Fri, Feb 20, 2015 at 10:04 PM, Junio C Hamano <gitster@pobox.com> wrote:
>> Ævar Arnfjörð Bjarmason <avarab@gmail.com> writes:
>>
>>> I actually ran this a few times while testing it, so this is a before
>>> and after on a hot cache of linux.git with 406 tags v.s. ~140k. I ran
>>> the gc + repack + bitmaps for both repos noted in an earlier reply of
>>> mine, and took the fastest run out of 3:
>>>
>>>     $ time (git log master -100 >/dev/null)
>>>     Before: real    0m0.021s
>>>     After: real    0m2.929s
>>
>> Do you force --decorate with some config?  Or do you see similar
>> performance difference with "git rev-parse master", too?
>
> Yes, I had log.decorate=short set in my config. With --no-decorate:
>
>     $ time (git log --no-decorate -100 >/dev/null)
>     # Before: real    0m0.010s
>     # After: real    0m0.065s
There you have the answer to your earlier question, then, which was:
Show 5 quoted lines
>> tl;dr: After some more testing it turns out the performance issues we
>> have are almost entirely due to the number of refs. Some of these I
>> knew about and were obvious (e..g. git pull), but some aren't so
>> obvious (why does "git log" without "--all" slow down as a function of
>> the overall number of refs?).
Previous: Ævar Arnfjörð BjarmasonNext: Sebastian Schuberth
Message 12 of 28 in “Git Scaling: What factors most affect Git performance for a large repo?”
  1. Stephen MortonFeb 19, 2015
  2. Stefan BellerFeb 19, 2015
  3. Stephen MortonFeb 19, 2015
  4. Stefan BellerFeb 19, 2015
  5. Ævar Arnfjörð BjarmasonFeb 19, 2015
  6. Duy NguyenFeb 20, 2015
  7. Ævar Arnfjörð BjarmasonFeb 20, 2015
  8. Ævar Arnfjörð BjarmasonFeb 20, 2015
  9. Ævar Arnfjörð BjarmasonFeb 20, 2015
  10. Junio C HamanoFeb 20, 2015
  11. Ævar Arnfjörð BjarmasonMar 2, 2015
  12. Junio C HamanoMar 2, 2015
  13. Sebastian SchuberthFeb 20, 2015
  14. Michael HaggertyFeb 24, 2015
  15. Ævar Arnfjörð BjarmasonMar 2, 2015
  16. Duy NguyenFeb 21, 2015
  17. Duy NguyenFeb 19, 2015
  18. David TurnerFeb 20, 2015
  19. Junio C HamanoFeb 20, 2015
  20. David TurnerFeb 23, 2015
  21. Duy NguyenFeb 21, 2015
  22. Duy NguyenFeb 25, 2015
  23. brian m. carlsonFeb 20, 2015
  24. Stephen MortonFeb 20, 2015
  25. Matthieu MoyFeb 20, 2015
  26. brian m. carlsonFeb 20, 2015
  27. Sebastian SchuberthFeb 20, 2015
  28. brian m. carlsonFeb 20, 2015

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