[MERGE] faster log - hooray!

[Karl Fogel]

Ian Clatworthy <ian.clatworthy at internode.on.net> writes:
> Benchmark results are attached for the emacs-merges trunk.
> See my earlier emails on this topic for an explanation of the
> various benchmarks run. I'll run some more benchmarks tonight
> on a MySQL branch and an OpenOffice.org branch to confirm the
> benchmark results are more broadly applicable than just for Emacs.
>
> [...]
>
> Finally, log -v performance remains an issue. I plan/expect to
> resolve that as part of the split-inventory format work. (I can't
> see any obvious way to speed up the current implementation until
> we can generate deltas faster.)

Coincidentally, I'm also doing some tests with an Emacs repository,
(though I think not the same one).

Regarding 'log -v', the data below probably won't tell you anything you
don't already know, but just in case:

  $ mkdir emacs-bzr
  Shared repository with trees (format: 1.12-preview or 1.9)
  Location:
    shared repository: .
  $ cd emacs-bzr
  $ bzr init-repo --1.9
  $ time bzr branch \
    bzr://bzr.notengoamigos.org/emacs-merges-ce/master/ emacs-merges-ce-master
  Branched 94342 revision(s).
  
  real    15m35.636s
  user    5m47.774s
  sys     0m10.849s
  $ cd emacs-merges-ce-master
  $ time bzr log > log.out
  
  real        1m14.041s
  user        1m12.181s
  sys        0m1.016s
  $ ls -lh log.out
  -rw-r--r-- 1 kfogel kfogel 28M 2009-01-28 14:18 log.out

  ### Compare with a ChangeLog generated from CVS... ###

  $ ls -lh ../../emacs-cvs/cvs2cl-ChangeLog
  -rw-r--r-- 1 kfogel users 24M 2009-01-28 00:22 \
      ../../emacs-cvs/cvs2cl-ChangeLog

  ### ...okay, seems reasonable (the formats differ, of course). ###

  ### Now try generating a log that has all the information I need to ###
  ### start spot-checking this repository against the CVS record:     ###

  $ time bzr log --long -v > log-long-verbose.out

  ### Taking a very long time, more than half an hour so far. ###
  ### There should be 94342 revisions, according to log.out.  ###
  ###                                                         ###
  ### At the rate it's going, I've calculated it will take    ###
  ### abut a day and a half to complete.                      ###