view tests/test-show.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

  $ cat >> $HGRCPATH << EOF
  > [extensions]
  > show =
  > EOF

No arguments shows available views

  $ hg init empty
  $ cd empty
  $ hg show
  available views:
  
  bookmarks -- bookmarks and their associated changeset
  stack -- current line of work
  work -- changesets that aren't finished
  
  abort: no view requested
  (use "hg show VIEW" to choose a view)
  [255]

`hg help show` prints available views

  $ hg help show
  hg show VIEW
  
  show various repository information
  
      A requested view of repository data is displayed.
  
      If no view is requested, the list of available views is shown and the
      command aborts.
  
      Note:
         There are no backwards compatibility guarantees for the output of this
         command. Output may change in any future Mercurial release.
  
         Consumers wanting stable command output should specify a template via
         "-T/--template".
  
      List of available views:
  
      bookmarks   bookmarks and their associated changeset
  
      stack       current line of work
  
      work        changesets that aren't finished
  
  (use 'hg help -e show' to show help for the show extension)
  
  options:
  
   -T --template TEMPLATE display with template
  
  (some details hidden, use --verbose to show complete help)

Unknown view prints error

  $ hg show badview
  abort: unknown view: badview
  (run "hg show" to see available views)
  [255]

HGPLAIN results in abort

  $ HGPLAIN=1 hg show bookmarks
  abort: must specify a template in plain mode
  (invoke with -T/--template to control output format)
  [255]

But not if a template is specified

  $ HGPLAIN=1 hg show bookmarks -T '{bookmark}\n'
  (no bookmarks set)

  $ cd ..

bookmarks view with no bookmarks prints empty message

  $ hg init books
  $ cd books
  $ touch f0
  $ hg -q commit -A -m initial

  $ hg show bookmarks
  (no bookmarks set)

bookmarks view shows bookmarks in an aligned table

  $ echo book1 > f0
  $ hg commit -m 'commit for book1'
  $ echo book2 > f0
  $ hg commit -m 'commit for book2'

  $ hg bookmark -r 1 book1
  $ hg bookmark a-longer-bookmark

  $ hg show bookmarks
  * a-longer-bookmark    7b57
    book1                b757

A custom bookmarks template works

  $ hg show bookmarks -T '{node} {bookmark} {active}\n'
  7b5709ab64cbc34da9b4367b64afff47f2c4ee83 a-longer-bookmark True
  b757f780b8ffd71267c6ccb32e0882d9d32a8cc0 book1 False

bookmarks JSON works

  $ hg show bookmarks -T json
  [
   {
    "active": true,
    "bookmark": "a-longer-bookmark",
    "longestbookmarklen": 17,
    "node": "7b5709ab64cbc34da9b4367b64afff47f2c4ee83",
    "nodelen": 4
   },
   {
    "active": false,
    "bookmark": "book1",
    "longestbookmarklen": 17,
    "node": "b757f780b8ffd71267c6ccb32e0882d9d32a8cc0",
    "nodelen": 4
   }
  ]

JSON works with no bookmarks

  $ hg book -d a-longer-bookmark
  $ hg book -d book1
  $ hg show bookmarks -T json
  [
  ]

commands.show.aliasprefix aliases values to `show <view>`

  $ hg --config commands.show.aliasprefix=s sbookmarks
  (no bookmarks set)

  $ hg --config commands.show.aliasprefix=sh shwork
  @  7b57 commit for book2
  o  b757 commit for book1
  o  ba59 initial

  $ hg --config commands.show.aliasprefix='s sh' swork
  @  7b57 commit for book2
  o  b757 commit for book1
  o  ba59 initial

  $ hg --config commands.show.aliasprefix='s sh' shwork
  @  7b57 commit for book2
  o  b757 commit for book1
  o  ba59 initial

The aliases don't appear in `hg config`

  $ hg --config commands.show.aliasprefix=s config alias
  [1]

Doesn't overwrite existing alias

  $ hg --config alias.swork='log -r .' --config commands.show.aliasprefix=s swork
  changeset:   2:7b5709ab64cb
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     commit for book2
  

  $ hg --config alias.swork='log -r .' --config commands.show.aliasprefix=s config alias
  alias.swork=log -r .

  $ cd ..