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Re: [PATCH 3/3] revision: insert unsorted, then sort in prepare_revision_walk()

From
MFMartin Fick <mfick@codeaurora.org>
Date
Apr 2, 2012, 23:16 UTC
Message-ID
<201204021716.22842.mfick@codeaurora.org>
In-Reply-To
<20120402203728.GB26503@sigill.intra.peff.net>
On Monday, April 02, 2012 02:37:28 pm Jeff King wrote:
> On Mon, Apr 02, 2012 at 09:51:21AM -0700, Shawn O. Pearce 
wrote:
Show 7 quoted lines
> > Probably. But we tend to hate caches in Git because
> > they can get stale and need to be rebuilt, and are
> > redundant with the base data. The mythical "pack v4"
> > work was going to approach this problem by storing the
> > commit timestamps uncompressed in a more machine
> > friendly format. Unfortunately the work has been
> > stalled for years.
...
Show 5 quoted lines
> So it's sort-of a cache, in that it's redundant with the
> actual data. But staleness and writing issues are a lot
> simpler, since it only gets updated when we index the
> pack (and the pack index in general is a similar
> concept;

... except that in the case of timestamps, it never even gets stale, it simply misses some entries or keeps entries around which should go away. So even if the pack files are rebuilt and someone forgets to update the timestamp index, it shouldn't cause any problems: the timestamps which are there should still work and likely will still be useful,

-Martin
-- 
Employee of Qualcomm Innovation Center, Inc. which is a 
member of Code Aurora Forum
Previous: Jeff KingNext: Nguyen Thai Ngoc Duy
Message 23 of 37 in “Git push performance problems with ~100K refs”
  1. Martin FickMar 30, 2012
  2. Junio C HamanoMar 30, 2012
  3. Martin FickMar 30, 2012
  4. Jeff KingMar 30, 2012
  5. Jeff KingMar 30, 2012
  6. Martin FickMar 30, 2012
  7. 1/3 add mergesort() for linked listsRené Scharfe, Mar 31, 2012
  8. Junio C HamanoApr 5, 2012
  9. René ScharfeApr 8, 2012
  10. Junio C HamanoApr 9, 2012
  11. Stephen BoydApr 11, 2012
  12. Junio C HamanoApr 11, 2012
  13. 2/3 commit: use mergesort() in commit_list_sort_by_date()René Scharfe, Mar 31, 2012
  14. 3/3 revision: insert unsorted, then sort in prepare_revision_walk()René Scharfe, Mar 31, 2012
  15. Martin FickMar 31, 2012
  16. Junio C HamanoMar 31, 2012
  17. Martin FickApr 2, 2012
  18. Shawn PearceApr 2, 2012
  19. Martin FickApr 2, 2012
  20. Shawn PearceApr 2, 2012
  21. Jeff KingApr 2, 2012
  22. Jeff KingApr 2, 2012
  23. Martin FickApr 2, 2012
  24. Nguyen Thai Ngoc DuyApr 3, 2012
  25. Martin FickApr 3, 2012
  26. 0/3 Commit cacheNguyễn Thái Ngọc Duy, Apr 3, 2012
  27. 1/3 parse_commit_buffer: rename a confusing variable nameNguyễn Thái Ngọc Duy, Apr 3, 2012
  28. 2/3 Add commit cache to help speed up commit traversalNguyễn Thái Ngọc Duy, Apr 3, 2012
  29. 3/3 Add parse_commit_for_rev() to take advantage of sha1-cacheNguyễn Thái Ngọc Duy, Apr 3, 2012
  30. Nguyen Thai Ngoc DuyApr 5, 2012
  31. Shawn PearceApr 6, 2012
  32. Nguyen Thai Ngoc DuyApr 7, 2012
  33. Nguyen Thai Ngoc DuyApr 3, 2012
  34. Jeff KingApr 2, 2012
  35. René ScharfeApr 2, 2012
  36. Jeff KingApr 3, 2012
  37. Jeff KingApr 3, 2012

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