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Re: More precise tag following

From
Simon 'corecode' Schubert <corecode@fs.ei.tum.de>
Date
Jan 27, 2007, 13:50 UTC
Message-ID
<45BB5888.9020608@fs.ei.tum.de>
In-Reply-To
<Pine.LNX.4.63.0701271352170.22628@wbgn013.biozentrum.uni-wuerzburg.de>
Johannes Schindelin wrote:
Show 6 quoted lines
> It is slower than Subversion's counterpart, just because SVN's blame 
> sucks. You cannot find out the _relevant_ information easily, i.e. once 
> you merged something, the _merge_ gets attributed for the change (at least 
> the last time I tried it).
> 
> So, don't blame blame for being useful in git.
Your reasoning is backwards.  Git's blame (or fwiw, rev-list path.name) is not slower because it is doing a better job (I can't tell, I don't use svn), but because it uses an algorithm which doesn't scale.  rev-list and blame are O(number of commits between HEAD and root) and not O(number of commits affecting path).  It might be sufficient for git.git, but certainly not for projects with a long history.  we are talking KDE, FreeBSD, OOo, something like this.  They each got about 400k commits.  It takes literally *minutes* to get a rev-list or a blame for a certain path.  The algorithm simply does not scale.  And this has nothing to do with superior output, because hg does it in O(num_of_file_revs), so it *can* be done.
> Of course, you could introduce a cache, but then, I don't run blame _that_ 
> often.
I don't think a cache is the right way.  I'd call the right idea "auxillary information".
> Besides, we already introduced an orthogonal historisation by reflogs, and 
> your method would not cope gracefully with that, would it?
I don't see how reflogs can play into this.  After all we're talking about the series of commits the blob experienced to get into its current state, not the series of actions it took this repo to contain this blob.
cheers
  simon
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Previous: Johannes SchindelinNext: Jakub Narebski
Message 9 of 92 in “More precise tag following”
  1. Junio C HamanoJan 26, 2007
  2. Junio C HamanoJan 26, 2007
  3. Shawn O. PearceJan 27, 2007
  4. Junio C HamanoJan 27, 2007
  5. Jeff KingJan 27, 2007
  6. Nicolas PitreJan 27, 2007
  7. Simon 'corecode' SchubertJan 27, 2007
  8. Johannes SchindelinJan 27, 2007
  9. Simon 'corecode' SchubertJan 27, 2007
  10. Jakub NarebskiJan 27, 2007
  11. Linus TorvaldsJan 27, 2007
  12. Johannes SchindelinJan 27, 2007
  13. Simon 'corecode' SchubertJan 27, 2007
  14. Johannes SchindelinJan 27, 2007
  15. Simon 'corecode' SchubertJan 27, 2007
  16. Nicolas PitreJan 27, 2007
  17. Linus TorvaldsJan 27, 2007
  18. Linus TorvaldsJan 27, 2007
  19. Junio C HamanoJan 27, 2007
  20. Linus TorvaldsJan 27, 2007
  21. Junio C HamanoJan 28, 2007
  22. git-blame --porcelain: quote filename in c-style when needed.Junio C Hamano, Jan 28, 2007
  23. git-blame --incremental: don't use pagerRené Scharfe, Jan 28, 2007
  24. Junio C HamanoJan 28, 2007
  25. Junio C HamanoJan 28, 2007
  26. René ScharfeJan 29, 2007
  27. git blame --progressJunio C Hamano, Jan 29, 2007
  28. Simon 'corecode' SchubertJan 29, 2007
  29. Alex RiesenJan 29, 2007
  30. Matthias LederhoferJan 29, 2007
  31. Junio C HamanoJan 29, 2007
  32. René ScharfeJan 29, 2007
  33. Linus TorvaldsJan 29, 2007
  34. Junio C HamanoJan 30, 2007
  35. Linus TorvaldsJan 28, 2007
  36. Junio C HamanoJan 28, 2007
  37. Linus TorvaldsJan 28, 2007
  38. Junio C HamanoJan 28, 2007
  39. document 'blame --incremental'Junio C Hamano, Jan 28, 2007
  40. Junio C HamanoJan 28, 2007
  41. Jeff KingJan 28, 2007
  42. Junio C HamanoJan 30, 2007
  43. Shawn O. PearceJan 30, 2007
  44. Linus TorvaldsJan 30, 2007
  45. Junio C HamanoJan 28, 2007
  46. Shawn O. PearceJan 29, 2007
  47. Junio C HamanoJan 29, 2007
  48. Shawn O. PearceJan 29, 2007
  49. Linus TorvaldsJan 29, 2007
  50. Simon 'corecode' SchubertJan 29, 2007
  51. Theodore TsoJan 29, 2007
  52. Linus TorvaldsJan 29, 2007
  53. Jakub NarebskiJan 29, 2007
  54. Shawn O. PearceJan 29, 2007
  55. Jakub NarebskiJan 29, 2007
  56. Shawn O. PearceFeb 9, 2007
  57. David KågedalJan 31, 2007
  58. David KågedalJan 31, 2007
  59. Peter EriksenJan 31, 2007
  60. David KågedalJan 31, 2007
  61. Peter EriksenJan 31, 2007
  62. Jakub NarebskiJan 31, 2007
  63. David KågedalJan 31, 2007
  64. Simon 'corecode' SchubertJan 27, 2007
  65. Johannes SchindelinJan 27, 2007
  66. Simon 'corecode' SchubertJan 27, 2007
  67. Johannes SchindelinJan 27, 2007
  68. Jakub NarebskiJan 27, 2007
  69. Linus TorvaldsJan 27, 2007
  70. Linus TorvaldsJan 27, 2007
  71. Jakub NarebskiJan 27, 2007
  72. Linus TorvaldsJan 27, 2007
  73. Chris LeeJan 27, 2007
  74. Theodore TsoJan 28, 2007
  75. Linus TorvaldsJan 28, 2007
  76. David LangJan 28, 2007
  77. Nicolas PitreJan 29, 2007
  78. Linus TorvaldsJan 29, 2007
  79. Nicolas PitreJan 29, 2007
  80. Chris LeeJan 29, 2007
  81. Eric WongJan 29, 2007
  82. Eric WongJan 30, 2007
  83. Eric WongJan 30, 2007
  84. Eric WongJan 30, 2007
  85. Jakub NarebskiJan 27, 2007
  86. Jeff KingJan 27, 2007
  87. Linus TorvaldsJan 27, 2007
  88. Jeff KingJan 27, 2007
  89. Theodore TsoJan 28, 2007
  90. Randal L. SchwartzJan 28, 2007
  91. Jeff KingJan 28, 2007
  92. Shawn O. PearceJan 28, 2007

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