view tests/test-directaccess.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

Tests for access level on hidden commits by various commands on based of their
type.

Setting the required config to start this

  $ cat >> $HGRCPATH <<EOF
  > [experimental]
  > evolution=createmarkers, allowunstable
  > directaccess=True
  > directaccess.revnums=True
  > [extensions]
  > amend =
  > EOF

  $ hg init repo
  $ cd repo
  $ for ch in a b c; do touch $ch; echo "foo" >> $ch; hg ci -Aqm "Added "$ch; done

  $ hg log -G -T '{rev}:{node} {desc}' --hidden
  @  2:28ad74487de9599d00d81085be739c61fc340652 Added c
  |
  o  1:29becc82797a4bc11ec8880b58eaecd2ab3e7760 Added b
  |
  o  0:18d04c59bb5d2d4090ad9a5b59bd6274adb63add Added a
  
  $ echo "bar" >> c
  $ hg amend

  $ hg log -G -T '{rev}:{node} {desc}' --hidden
  @  3:2443a0e664694756d8b435d06b6ad84f941b6fc0 Added c
  |
  | x  2:28ad74487de9599d00d81085be739c61fc340652 Added c
  |/
  o  1:29becc82797a4bc11ec8880b58eaecd2ab3e7760 Added b
  |
  o  0:18d04c59bb5d2d4090ad9a5b59bd6274adb63add Added a
  
Testing read only commands on the hidden revision

Testing with rev number

  $ hg exp 2 --config experimental.directaccess.revnums=False
  abort: hidden revision '2' was rewritten as: 2443a0e66469!
  (use --hidden to access hidden revisions)
  [255]

  $ hg exp 2
  # HG changeset patch
  # User test
  # Date 0 0
  #      Thu Jan 01 00:00:00 1970 +0000
  # Node ID 28ad74487de9599d00d81085be739c61fc340652
  # Parent  29becc82797a4bc11ec8880b58eaecd2ab3e7760
  Added c
  
  diff -r 29becc82797a -r 28ad74487de9 c
  --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
  +++ b/c	Thu Jan 01 00:00:00 1970 +0000
  @@ -0,0 +1,1 @@
  +foo

  $ hg log -r 2
  changeset:   2:28ad74487de9
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  obsolete:    rewritten using amend as 3:2443a0e66469
  summary:     Added c
  
  $ hg identify -r 2
  28ad74487de9

  $ hg status --change 2
  A c

  $ hg status --change 2 --config experimental.directaccess.revnums=False
  abort: hidden revision '2' was rewritten as: 2443a0e66469!
  (use --hidden to access hidden revisions)
  [255]

  $ hg diff -c 2
  diff -r 29becc82797a -r 28ad74487de9 c
  --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
  +++ b/c	Thu Jan 01 00:00:00 1970 +0000
  @@ -0,0 +1,1 @@
  +foo

Testing with hash

`hg export`

  $ hg exp 28ad74
  # HG changeset patch
  # User test
  # Date 0 0
  #      Thu Jan 01 00:00:00 1970 +0000
  # Node ID 28ad74487de9599d00d81085be739c61fc340652
  # Parent  29becc82797a4bc11ec8880b58eaecd2ab3e7760
  Added c
  
  diff -r 29becc82797a -r 28ad74487de9 c
  --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
  +++ b/c	Thu Jan 01 00:00:00 1970 +0000
  @@ -0,0 +1,1 @@
  +foo

`hg log`

  $ hg log -r 28ad74
  changeset:   2:28ad74487de9
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  obsolete:    rewritten using amend as 3:2443a0e66469
  summary:     Added c
  
`hg cat`

  $ hg cat -r 28ad74 c
  foo

`hg diff`

  $ hg diff -c 28ad74
  diff -r 29becc82797a -r 28ad74487de9 c
  --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
  +++ b/c	Thu Jan 01 00:00:00 1970 +0000
  @@ -0,0 +1,1 @@
  +foo

`hg files`

  $ hg files -r 28ad74
  a
  b
  c

`hg identify`

  $ hg identify -r 28ad74
  28ad74487de9

`hg annotate`

  $ hg annotate -r 28ad74 a
  0: foo

`hg status`

  $ hg status --change 28ad74
  A c

`hg archive`

This should not throw error
  $ hg archive -r 28ad74 foo

`hg update`

  $ hg up 28ad74
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset 28ad74487de9
  (hidden revision '28ad74487de9' was rewritten as: 2443a0e66469)

  $ hg up 3
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ hg up
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved

`hg revert`

  $ hg revert -r 28ad74 --all
  reverting c

  $ hg diff
  diff -r 2443a0e66469 c
  --- a/c	Thu Jan 01 00:00:00 1970 +0000
  +++ b/c	Thu Jan 01 00:00:00 1970 +0000
  @@ -1,2 +1,1 @@
   foo
  -bar

Test special hash/rev

  $ hg log -qr 'null:wdir() & 000000000000'
  -1:000000000000
  $ hg log -qr 'null:wdir() & ffffffffffff'
  2147483647:ffffffffffff
  $ hg log -qr 'null:wdir() & rev(-1)'
  -1:000000000000
  $ hg log -qr 'null:wdir() & rev(2147483647)'
  2147483647:ffffffffffff
  $ hg log -qr 'null:wdir() & 2147483647'
  2147483647:ffffffffffff

Commands with undefined intent should not work right now

  $ hg phase -r 28ad74
  abort: hidden revision '28ad74' was rewritten as: 2443a0e66469!
  (use --hidden to access hidden revisions)
  [255]

  $ hg phase -r 2
  abort: hidden revision '2' was rewritten as: 2443a0e66469!
  (use --hidden to access hidden revisions)
  [255]

Setting a bookmark will make that changeset unhidden, so this should come in end

  $ hg bookmarks -r 28ad74 book
  bookmarking hidden changeset 28ad74487de9
  (hidden revision '28ad74487de9' was rewritten as: 2443a0e66469)

  $ hg bookmarks
     book                      2:28ad74487de9