view tests/test-phase-archived.t @ 44363:f7459da77f23

nodemap: introduce an option to use mmap to read the nodemap mapping

The performance and memory benefit is much greater if we don't have to copy all
the data in memory for each information. So we introduce an option (on by
default) to read the data using mmap.

This changeset is the last one definition the API for index support nodemap
data. (they have to be able to use the mmaping).

Below are some benchmark comparing the best we currently have in 5.3 with the
final step of this series (using the persistent nodemap implementation in
Rust). The benchmark run `hg perfindex` with various revset and the following
variants:

Before:

 * do not use the persistent nodemap
 * use the CPython implementation of the index for nodemap
 * use mmapping of the changelog index

After:

 * use the MixedIndex Rust code, with the NodeTree object for nodemap access
   (still in review)
 * use the persistent nodemap data from disk
 * access the persistent nodemap data through mmap
 * use mmapping of the changelog index

The persistent nodemap greatly speed up  most operation on very large
repositories. Some of the previously very fast lookup end up a bit slower because
the persistent nodemap has to be setup. However the absolute slowdown is very
small and won't matters in the big picture.

Here are some numbers (in seconds) for the reference copy of mozilla-try:

Revset            Before   After     abs-change speedup

-10000:           0.004622 0.005532   0.000910  ×   0.83
-10:              0.000050 0.000132   0.000082  ×   0.37
tip               0.000052 0.000085   0.000033  ×   0.61
0 + (-10000:)     0.028222 0.005337  -0.022885  ×   5.29
0                 0.023521 0.000084  -0.023437  × 280.01
(-10000:) + 0     0.235539 0.005308  -0.230231  ×  44.37
(-10:) + :9       0.232883 0.000180  -0.232703  ×1293.79
(-10000:) + (:99) 0.238735 0.005358  -0.233377  ×  44.55
:99 + (-10000:)   0.317942 0.005593  -0.312349  ×  56.84
:9 + (-10:)       0.313372 0.000179  -0.313193  ×1750.68
:9                0.316450 0.000143  -0.316307  ×2212.93


On smaller repositories, the cost of nodemap related operation is not as big, so
the win is much more modest. Yet it helps shaving a handful of millisecond here
and there.

Here are some numbers (in seconds) for the reference copy of mercurial:

Revset            Before   After     abs-change speedup
-10:              0.000065 0.000097   0.000032  × 0.67
tip               0.000063 0.000078   0.000015  × 0.80
0                 0.000561 0.000079  -0.000482  × 7.10
-10000:           0.004609 0.003648  -0.000961  × 1.26
0 + (-10000:)     0.005023 0.003715  -0.001307  × 1.35
(-10:) + :9       0.002187 0.000108  -0.002079  ×20.25
(-10000:) + 0     0.006252 0.003716  -0.002536  × 1.68
(-10000:) + (:99) 0.006367 0.003707  -0.002660  × 1.71
:9 + (-10:)       0.003846 0.000110  -0.003736  ×34.96
:9                0.003854 0.000099  -0.003755  ×38.92
:99 + (-10000:)   0.007644 0.003778  -0.003866  × 2.02

Differential Revision: https://phab.mercurial-scm.org/D7894

=========================================================
Test features and behaviors related to the archived phase
=========================================================

  $ cat << EOF >> $HGRCPATH
  > [format]
  > internal-phase=yes
  > [extensions]
  > strip=
  > [experimental]
  > EOF

  $ hg init repo
  $ cd repo
  $ echo  root > a
  $ hg add a
  $ hg ci -m 'root'

Test that bundle can unarchive a changeset
------------------------------------------

  $ echo foo >> a
  $ hg st
  M a
  $ hg ci -m 'unbundletesting'
  $ hg log -G
  @  changeset:   1:883aadbbf309
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     unbundletesting
  |
  o  changeset:   0:c1863a3840c6
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     root
  
  $ hg strip --soft --rev '.'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  saved backup bundle to $TESTTMP/repo/.hg/strip-backup/883aadbbf309-efc55adc-backup.hg
  $ hg log -G
  @  changeset:   0:c1863a3840c6
     tag:         tip
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     root
  
  $ hg log -G --hidden
  o  changeset:   1:883aadbbf309
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     unbundletesting
  |
  @  changeset:   0:c1863a3840c6
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     root
  
  $ hg unbundle .hg/strip-backup/883aadbbf309-efc55adc-backup.hg
  adding changesets
  adding manifests
  adding file changes
  added 0 changesets with 0 changes to 1 files
  (run 'hg update' to get a working copy)
  $ hg log -G
  o  changeset:   1:883aadbbf309
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     unbundletesting
  |
  @  changeset:   0:c1863a3840c6
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     root
  

Test that history rewriting command can use the archived phase when allowed to
------------------------------------------------------------------------------

  $ hg up 'desc(unbundletesting)'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo bar >> a
  $ hg commit --amend --config experimental.cleanup-as-archived=yes
  $ hg log -G
  @  changeset:   2:d1e73e428f29
  |  tag:         tip
  |  parent:      0:c1863a3840c6
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     unbundletesting
  |
  o  changeset:   0:c1863a3840c6
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     root
  
  $ hg log -G --hidden
  @  changeset:   2:d1e73e428f29
  |  tag:         tip
  |  parent:      0:c1863a3840c6
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     unbundletesting
  |
  | o  changeset:   1:883aadbbf309
  |/   user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    summary:     unbundletesting
  |
  o  changeset:   0:c1863a3840c6
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     root
  
  $ ls -1 .hg/strip-backup/
  883aadbbf309-efc55adc-amend.hg
  883aadbbf309-efc55adc-backup.hg
  $ hg unbundle .hg/strip-backup/883aadbbf309*amend.hg
  adding changesets
  adding manifests
  adding file changes
  added 0 changesets with 0 changes to 1 files
  (run 'hg update' to get a working copy)
  $ hg log -G
  @  changeset:   2:d1e73e428f29
  |  tag:         tip
  |  parent:      0:c1863a3840c6
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     unbundletesting
  |
  | o  changeset:   1:883aadbbf309
  |/   user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    summary:     unbundletesting
  |
  o  changeset:   0:c1863a3840c6
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     root