view tests/test-basic.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

Create a repository:

#if no-extraextensions
  $ hg config
  devel.all-warnings=true
  devel.default-date=0 0
  extensions.fsmonitor= (fsmonitor !)
  largefiles.usercache=$TESTTMP/.cache/largefiles
  lfs.usercache=$TESTTMP/.cache/lfs
  ui.slash=True
  ui.interactive=False
  ui.merge=internal:merge
  ui.mergemarkers=detailed
  ui.promptecho=True
  web.address=localhost
  web\.ipv6=(?:True|False) (re)
  web.server-header=testing stub value
#endif

  $ hg init t
  $ cd t

Prepare a changeset:

  $ echo a > a
  $ hg add a

  $ hg status
  A a

Writes to stdio succeed and fail appropriately

#if devfull
  $ hg status 2>/dev/full
  A a

  $ hg status >/dev/full
  abort: No space left on device
  [255]
#endif

#if devfull
  $ hg status >/dev/full 2>&1
  [255]

  $ hg status ENOENT 2>/dev/full
  [255]
#endif

  $ hg commit -m test

This command is ancient:

  $ hg history
  changeset:   0:acb14030fe0a
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     test
  

Verify that updating to revision 0 via commands.update() works properly

  $ cat <<EOF > update_to_rev0.py
  > from mercurial import commands, hg, ui as uimod
  > myui = uimod.ui.load()
  > repo = hg.repository(myui, path=b'.')
  > commands.update(myui, repo, rev=b"0")
  > EOF
  $ hg up null
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ "$PYTHON" ./update_to_rev0.py
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg identify -n
  0


Poke around at hashes:

  $ hg manifest --debug
  b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3 644   a

  $ hg cat a
  a

Verify should succeed:

  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 1 changesets with 1 changes to 1 files

Repository root:

  $ hg root
  $TESTTMP/t
  $ hg log -l1 -T '{reporoot}\n'
  $TESTTMP/t
  $ hg root -Tjson | sed 's|\\\\|\\|g'
  [
   {
    "hgpath": "$TESTTMP/t/.hg",
    "reporoot": "$TESTTMP/t",
    "storepath": "$TESTTMP/t/.hg/store"
   }
  ]

At the end...

  $ cd ..

Status message redirection:

  $ hg init empty

 status messages are sent to stdout by default:

  $ hg outgoing -R t empty -Tjson 2>/dev/null
  comparing with empty
  searching for changes
  [
   {
    "bookmarks": [],
    "branch": "default",
    "date": [0, 0],
    "desc": "test",
    "node": "acb14030fe0a21b60322c440ad2d20cf7685a376",
    "parents": ["0000000000000000000000000000000000000000"],
    "phase": "draft",
    "rev": 0,
    "tags": ["tip"],
    "user": "test"
   }
  ]

 which can be configured to send to stderr, so the output wouldn't be
 interleaved:

  $ cat <<'EOF' >> "$HGRCPATH"
  > [ui]
  > message-output = stderr
  > EOF
  $ hg outgoing -R t empty -Tjson 2>/dev/null
  [
   {
    "bookmarks": [],
    "branch": "default",
    "date": [0, 0],
    "desc": "test",
    "node": "acb14030fe0a21b60322c440ad2d20cf7685a376",
    "parents": ["0000000000000000000000000000000000000000"],
    "phase": "draft",
    "rev": 0,
    "tags": ["tip"],
    "user": "test"
   }
  ]
  $ hg outgoing -R t empty -Tjson >/dev/null
  comparing with empty
  searching for changes

 this option should be turned off by HGPLAIN= since it may break scripting use:

  $ HGPLAIN= hg outgoing -R t empty -Tjson 2>/dev/null
  comparing with empty
  searching for changes
  [
   {
    "bookmarks": [],
    "branch": "default",
    "date": [0, 0],
    "desc": "test",
    "node": "acb14030fe0a21b60322c440ad2d20cf7685a376",
    "parents": ["0000000000000000000000000000000000000000"],
    "phase": "draft",
    "rev": 0,
    "tags": ["tip"],
    "user": "test"
   }
  ]

 but still overridden by --config:

  $ HGPLAIN= hg outgoing -R t empty -Tjson --config ui.message-output=stderr \
  > 2>/dev/null
  [
   {
    "bookmarks": [],
    "branch": "default",
    "date": [0, 0],
    "desc": "test",
    "node": "acb14030fe0a21b60322c440ad2d20cf7685a376",
    "parents": ["0000000000000000000000000000000000000000"],
    "phase": "draft",
    "rev": 0,
    "tags": ["tip"],
    "user": "test"
   }
  ]

Invalid ui.message-output option:

  $ hg log -R t --config ui.message-output=bad
  abort: invalid ui.message-output destination: bad
  [255]

Underlying message streams should be updated when ui.fout/ferr are set:

  $ cat <<'EOF' > capui.py
  > from mercurial import pycompat, registrar
  > cmdtable = {}
  > command = registrar.command(cmdtable)
  > @command(b'capui', norepo=True)
  > def capui(ui):
  >     out = ui.fout
  >     ui.fout = pycompat.bytesio()
  >     ui.status(b'status\n')
  >     ui.ferr = pycompat.bytesio()
  >     ui.warn(b'warn\n')
  >     out.write(b'stdout: %s' % ui.fout.getvalue())
  >     out.write(b'stderr: %s' % ui.ferr.getvalue())
  > EOF
  $ hg --config extensions.capui=capui.py --config ui.message-output=stdio capui
  stdout: status
  stderr: warn