view tests/test-sparse-revlog.t @ 40391:abbd077965c0

wireprotov2: support exposing linknode of file revisions

When supporting shallow file storage, clients may fetch file revisions
by changeset. But they may not readily know which changeset introduced a
specific file revision. The "linknode" is used to record which changeset
introduces which file revision.

This commit teaches the "filedata" and "filesdata" wire protocol commands
to expose the linknode for file revisions. The implementation is likely
wrong when hidden changesets are in play, since the linknode may refer to
a hidden changeset. We can deal with this problem later.

Differential Revision: https://phab.mercurial-scm.org/D5167

====================================
Test delta choice with sparse revlog
====================================

Sparse-revlog usually shows the most gain on Manifest. However, it is simpler
to general an appropriate file, so we test with a single file instead. The
goal is to observe intermediate snapshot being created.

We need a large enough file. Part of the content needs to be replaced
repeatedly while some of it changes rarely.

  $ bundlepath="$TESTDIR/artifacts/cache/big-file-churn.hg"

  $ expectedhash=`cat "$bundlepath".md5`
  $ if [ ! -f "$bundlepath" ]; then
  >     echo 'skipped: missing artifact, run "'"$TESTDIR"'/artifacts/scripts/generate-churning-bundle.py"'
  >     exit 80
  > fi
  $ currenthash=`f -M "$bundlepath" | cut -d = -f 2`
  $ if [ "$currenthash" != "$expectedhash" ]; then
  >     echo 'skipped: outdated artifact, md5 "'"$currenthash"'" expected "'"$expectedhash"'" run "'"$TESTDIR"'/artifacts/scripts/generate-churning-bundle.py"'
  >     exit 80
  > fi

  $ cat >> $HGRCPATH << EOF
  > [format]
  > sparse-revlog = yes
  > maxchainlen = 15
  > [storage]
  > revlog.optimize-delta-parent-choice = yes
  > EOF
  $ hg init sparse-repo
  $ cd sparse-repo
  $ hg unbundle $bundlepath
  adding changesets
  adding manifests
  adding file changes
  added 5001 changesets with 5001 changes to 1 files (+89 heads)
  new changesets 9706f5af64f4:d9032adc8114 (5001 drafts)
  (run 'hg heads' to see heads, 'hg merge' to merge)
  $ hg up
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to "d9032adc8114: commit #5000"
  89 other heads for branch "default"

  $ hg log --stat -r 0:3
  changeset:   0:9706f5af64f4
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     initial commit
  
   SPARSE-REVLOG-TEST-FILE |  10500 ++++++++++++++++++++++++++++++++++++++++++++++
   1 files changed, 10500 insertions(+), 0 deletions(-)
  
  changeset:   1:724907deaa5e
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     commit #1
  
   SPARSE-REVLOG-TEST-FILE |  1068 +++++++++++++++++++++++-----------------------
   1 files changed, 534 insertions(+), 534 deletions(-)
  
  changeset:   2:62c41bce3e5d
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     commit #2
  
   SPARSE-REVLOG-TEST-FILE |  1068 +++++++++++++++++++++++-----------------------
   1 files changed, 534 insertions(+), 534 deletions(-)
  
  changeset:   3:348a9cbd6959
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     commit #3
  
   SPARSE-REVLOG-TEST-FILE |  1068 +++++++++++++++++++++++-----------------------
   1 files changed, 534 insertions(+), 534 deletions(-)
  

  $ f -s .hg/store/data/*.d
  .hg/store/data/_s_p_a_r_s_e-_r_e_v_l_o_g-_t_e_s_t-_f_i_l_e.d: size=63002924
  $ hg debugrevlog *
  format : 1
  flags  : generaldelta
  
  revisions     :     5001
      merges    :      625 (12.50%)
      normal    :     4376 (87.50%)
  revisions     :     5001
      empty     :        0 ( 0.00%)
                     text  :        0 (100.00%)
                     delta :        0 (100.00%)
      snapshot  :      374 ( 7.48%)
        lvl-0   :              4 ( 0.08%)
        lvl-1   :             23 ( 0.46%)
        lvl-2   :             63 ( 1.26%)
        lvl-3   :            118 ( 2.36%)
        lvl-4   :            166 ( 3.32%)
      deltas    :     4627 (92.52%)
  revision size : 63002924
      snapshot  :  9888099 (15.69%)
        lvl-0   :         804262 ( 1.28%)
        lvl-1   :        1561380 ( 2.48%)
        lvl-2   :        2096696 ( 3.33%)
        lvl-3   :        2749539 ( 4.36%)
        lvl-4   :        2676222 ( 4.25%)
      deltas    : 53114825 (84.31%)
  
  chunks        :     5001
      0x78 (x)  :     5001 (100.00%)
  chunks size   : 63002924
      0x78 (x)  : 63002924 (100.00%)
  
  avg chain length  :        9
  max chain length  :       15
  max chain reach   : 28907121
  compression ratio :       27
  
  uncompressed data size (min/max/avg) : 346468 / 346472 / 346471
  full revision size (min/max/avg)     : 201008 / 201141 / 201065
  inter-snapshot size (min/max/avg)    : 11601 / 157413 / 24550
      level-1   (min/max/avg)          : 13061 / 157413 / 67886
      level-2   (min/max/avg)          : 11674 / 85631 / 33280
      level-3   (min/max/avg)          : 11602 / 42957 / 23301
      level-4   (min/max/avg)          : 11601 / 21475 / 16121
  delta size (min/max/avg)             : 10649 / 105465 / 11479
  
  deltas against prev  : 3966 (85.71%)
      where prev = p1  : 3922     (98.89%)
      where prev = p2  :    0     ( 0.00%)
      other            :   44     ( 1.11%)
  deltas against p1    :  611 (13.21%)
  deltas against p2    :   50 ( 1.08%)
  deltas against other :    0 ( 0.00%)