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Re: [PATCH 0/4] gc docs: modernize and fix the documentation

From
Jeff King <peff@peff.net>
Date
Mar 18, 2019, 21:51 UTC
Message-ID
<20190318215107.GH29661@sigill.intra.peff.net>
In-Reply-To
<20190318161502.7979-1-avarab@gmail.com>
On Mon, Mar 18, 2019 at 05:14:58PM +0100, Ævar Arnfjörð Bjarmason wrote:
Show 27 quoted lines
> This series is unrelated (and does not conflict with) my in-flight gc
> contention series
> (https://public-inbox.org/git/20190315155959.12390-1-avarab@gmail.com/),
> but the "git-gc" docs should be updated to discuss the
> core.filesRefLockTimeout option and how it impacts contention, see 8/8
> in that series for context. I.e. "you may have contention, but
> core.filesRefLockTimeout can mitigate blah blah".
> 
> I was going to do that, but then thought that we should also mention
> that on the server-side we mitigate most/all of the contention via the
> quarantine, see "QUARANTINE ENVIRONMENT" in
> git-receive-pack(1). I.e. we:
> 
>  1. Get the temp pack
>  2. OK it (fsck, hooks etc.)
>  3. Move *complete* previously temp packs over
>  4. Update the refs
> 
> I.e. we are immune from the "concurrently with another process" race,
> but of course something concurrently updating the "server" repo
> without a quarantine environment may be subject to that race.
> 
> The only problem is that the last couple of paragraphs may be
> wrong. That's just my understanding from a brief reading of
> 722ff7f876c ("receive-pack: quarantine objects until pre-receive
> accepts", 2016-10-03) so I didn't want to include that in this
> series. Peff (or others), any comments?

I don't think the quarantine stuff should impact contention at all. It's only quarantining the objects, which are the least contentious part of Git (because object content is idempotent, so we don't do any locking there, and with two racing processes, one will just "win").

-Peff
Previous: Ævar Arnfjörð BjarmasonNext: Ævar Arnfjörð Bjarmason
Message 20 of 64 in “gc docs: modernize and fix the documentation”
  1. 0/4 gc docs: modernize and fix the documentationÆvar Arnfjörð Bjarmason, Mar 18, 2019
  2. 1/4 gc docs: modernize the advice for manually running "gc"Ævar Arnfjörð Bjarmason, Mar 18, 2019
  3. Jeff KingMar 18, 2019
  4. Ævar Arnfjörð BjarmasonMar 18, 2019
  5. 2/4 gc docs: include the "gc.*" section from "config" in "gc"Ævar Arnfjörð Bjarmason, Mar 18, 2019
  6. Jeff KingMar 18, 2019
  7. Andreas HeidukMar 21, 2019
  8. Duy NguyenMar 19, 2019
  9. 3/4 gc docs: de-duplicate "OPTIONS" and "CONFIGURATION"Ævar Arnfjörð Bjarmason, Mar 18, 2019
  10. Jeff KingMar 18, 2019
  11. Ævar Arnfjörð BjarmasonMar 18, 2019
  12. Jeff KingMar 18, 2019
  13. 4/4 gc docs: downplay the usefulness of --aggressiveÆvar Arnfjörð Bjarmason, Mar 18, 2019
  14. Jonathan NiederMar 18, 2019
  15. Jeff KingMar 18, 2019
  16. Ævar Arnfjörð BjarmasonMar 18, 2019
  17. Jeff KingMar 18, 2019
  18. Johannes SixtMar 19, 2019
  19. Ævar Arnfjörð BjarmasonMar 19, 2019
  20. Jeff KingMar 18, 2019
  21. Ævar Arnfjörð BjarmasonMar 18, 2019
  22. Jeff KingMar 19, 2019
  23. Ævar Arnfjörð BjarmasonMay 6, 2019
  24. Jeff KingMay 7, 2019
  25. Ævar Arnfjörð BjarmasonMay 9, 2019
  26. Jeff KingJul 31, 2019
  27. Ævar Arnfjörð BjarmasonJul 31, 2019
  28. 00/10 gc docs: modernize and fix the documentationÆvar Arnfjörð Bjarmason, Mar 21, 2019
  29. 00/11 gc docs: modernize the advice for manually running "gc"Ævar Arnfjörð Bjarmason, Mar 22, 2019
  30. 01/11 gc docs: modernize the advice for manually running "gc"Ævar Arnfjörð Bjarmason, Mar 22, 2019
  31. 02/11 gc docs: stop noting "repack" flagsÆvar Arnfjörð Bjarmason, Mar 22, 2019
  32. 03/11 gc docs: clean grammar for "gc.bigPackThreshold"Ævar Arnfjörð Bjarmason, Mar 22, 2019
  33. 06/11 gc docs: fix formatting for "gc.writeCommitGraph"Ævar Arnfjörð Bjarmason, Mar 22, 2019
  34. 05/11 gc docs: re-flow the "gc.*" section in "config"Ævar Arnfjörð Bjarmason, Mar 22, 2019
  35. 07/11 gc docs: note how --aggressive impacts --window & --depthÆvar Arnfjörð Bjarmason, Mar 22, 2019
  36. 04/11 gc docs: include the "gc.*" section from "config" in "gc"Ævar Arnfjörð Bjarmason, Mar 22, 2019
  37. Todd ZullingerMar 30, 2019
  38. 00/11 gc docs: modernize and fix the documentationÆvar Arnfjörð Bjarmason, Apr 7, 2019
  39. 01/11 gc docs: modernize the advice for manually running "gc"Ævar Arnfjörð Bjarmason, Apr 7, 2019
  40. 02/11 gc docs: stop noting "repack" flagsÆvar Arnfjörð Bjarmason, Apr 7, 2019
  41. 03/11 gc docs: clean grammar for "gc.bigPackThreshold"Ævar Arnfjörð Bjarmason, Apr 7, 2019
  42. 04/11 gc docs: include the "gc.*" section from "config" in "gc"Ævar Arnfjörð Bjarmason, Apr 7, 2019
  43. 05/11 gc docs: re-flow the "gc.*" section in "config"Ævar Arnfjörð Bjarmason, Apr 7, 2019
  44. 06/11 gc docs: fix formatting for "gc.writeCommitGraph"Ævar Arnfjörð Bjarmason, Apr 7, 2019
  45. 07/11 gc docs: note how --aggressive impacts --window & --depthÆvar Arnfjörð Bjarmason, Apr 7, 2019
  46. 09/11 gc docs: note "gc --aggressive" in "fast-import"Ævar Arnfjörð Bjarmason, Apr 7, 2019
  47. 10/11 gc docs: clarify that "gc" doesn't throw away referenced objectsÆvar Arnfjörð Bjarmason, Apr 7, 2019
  48. 11/11 gc docs: remove incorrect reference to gc.auto=0Ævar Arnfjörð Bjarmason, Apr 7, 2019
  49. 08/11 gc docs: downplay the usefulness of --aggressiveÆvar Arnfjörð Bjarmason, Apr 7, 2019
  50. 10/11 gc docs: clarify that "gc" doesn't throw away referenced objectsÆvar Arnfjörð Bjarmason, Mar 22, 2019
  51. 08/11 gc docs: downplay the usefulness of --aggressiveÆvar Arnfjörð Bjarmason, Mar 22, 2019
  52. 11/11 gc docs: remove incorrect reference to gc.auto=0Ævar Arnfjörð Bjarmason, Mar 22, 2019
  53. 09/11 gc docs: note "gc --aggressive" in "fast-import"Ævar Arnfjörð Bjarmason, Mar 22, 2019
  54. 02/10 gc docs: stop noting "repack" flagsÆvar Arnfjörð Bjarmason, Mar 21, 2019
  55. 01/10 gc docs: modernize the advice for manually running "gc"Ævar Arnfjörð Bjarmason, Mar 21, 2019
  56. Junio C HamanoMar 22, 2019
  57. 03/10 gc docs: clean grammar for "gc.bigPackThreshold"Ævar Arnfjörð Bjarmason, Mar 21, 2019
  58. 04/10 gc docs: include the "gc.*" section from "config" in "gc"Ævar Arnfjörð Bjarmason, Mar 21, 2019
  59. 05/10 gc docs: re-flow the "gc.*" section in "config"Ævar Arnfjörð Bjarmason, Mar 21, 2019
  60. 06/10 gc docs: note how --aggressive impacts --window & --depthÆvar Arnfjörð Bjarmason, Mar 21, 2019
  61. 07/10 gc docs: downplay the usefulness of --aggressiveÆvar Arnfjörð Bjarmason, Mar 21, 2019
  62. 08/10 gc docs: note "gc --aggressive" in "fast-import"Ævar Arnfjörð Bjarmason, Mar 21, 2019
  63. 09/10 gc docs: clarify that "gc" doesn't throw away referenced objectsÆvar Arnfjörð Bjarmason, Mar 21, 2019
  64. 10/10 gc docs: remove incorrect reference to gc.auto=0Ævar Arnfjörð Bjarmason, Mar 21, 2019

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