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

From
brian m. carlson <sandals@crustytoothpaste.net>
Date
Feb 20, 2015, 17:16 UTC
Message-ID
<20150220171614.GA5730@vauxhall.crustytoothpaste.net>
In-Reply-To
<CAH8BJxEWDb0SDHPS_ZnPzz0QEbryw2GCv2RtJm2u_6rPH566hg@mail.gmail.com>
On Fri, Feb 20, 2015 at 11:06:44AM -0500, Stephen Morton wrote:
Show 7 quoted lines
>2. I'd not heard about bitmap indexes before this thread but it sounds
>like they should help me. In limited searching I can't find much
>useful documentation about them. It is also not clear to me if I have
>to explicitly run "git repack --write-bitmap-indexes" or if git will
>automatically detect when they're needed; first experiments seem to
>indicate that I need to explicitly generate them. I assume that once
>the index is there, git will just use it automatically.

Pack bitmaps are a way of speeding up clones and fetches by precomputing reachability information. Practically, this means that the initial "Counting objects" phase is instantaneous for clones and much faster for fetches.

The way I've done it in the past is to set repack.writeBitmaps = true in /etc/gitconfig on the server. (I highly recommend enabling reflogs in the same place.) Then you'll need to ensure that git gc runs periodically so that bitmaps are generated.

-- 
brian m. carlson / brian with sandals: Houston, Texas, US
+1 832 623 2791 | http://www.crustytoothpaste.net/~bmc | My opinion only
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Previous: Matthieu MoyNext: Sebastian Schuberth
Message 26 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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