====================================

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     echo 'skipped: outdated artifact, md5 "'"$currenthash"'" expected "'"$expectedhash"'" run "'"$TESTDIR"'/artifacts/scripts/generate-churning-bundle.py"'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

  > [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=74365490

  $ 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  :      101 ( 2.02%)

        lvl-0   :            101 ( 2.02%)

      deltas    :     4900 (97.98%)

  revision size : 74365490

      snapshot  : 20307865 (27.31%)

        lvl-0   :       20307865 (27.31%)

      deltas    : 54057625 (72.69%)

  chunks        :     5001

      0x78 (x)  :     5001 (100.00%)

  chunks size   : 74365490

      0x78 (x)  : 74365490 (100.00%)

  avg chain length  :       23

  max chain length  :       45

  max chain reach   : 11039464

  compression ratio :       23

  uncompressed data size (min/max/avg) : 346468 / 346472 / 346471

  full revision size (min/max/avg)     : 200927 / 201202 / 201067

  inter-snapshot size (min/max/avg)    : 0 / 0 / 0

  delta size (min/max/avg)             : 10649 / 103898 / 11032

  deltas against prev  : 4231 (86.35%)

      where prev = p1  : 4172     (98.61%)

      where prev = p2  :    0     ( 0.00%)

      other            :   59     ( 1.39%)

  deltas against p1    :  651 (13.29%)

  deltas against p2    :   18 ( 0.37%)

  deltas against other :    0 ( 0.00%)