view tests/test-unionrepo.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

#require no-reposimplestore

Test unionrepo functionality

Create one repository

  $ hg init repo1
  $ cd repo1
  $ touch repo1-0
  $ echo repo1-0 > f
  $ hg ci -Aqmrepo1-0
  $ touch repo1-1
  $ echo repo1-1 >> f
  $ hg ci -Aqmrepo1-1
  $ touch repo1-2
  $ echo repo1-2 >> f
  $ hg ci -Aqmrepo1-2
  $ hg log --template '{rev}:{node|short}  {desc|firstline}\n'
  2:68c0685446a3  repo1-2
  1:8a58db72e69d  repo1-1
  0:f093fec0529b  repo1-0
  $ tip1=`hg id -q`
  $ cd ..

- and a clone with a not-completely-trivial history

  $ hg clone -q repo1 --rev 0 repo2
  $ cd repo2
  $ touch repo2-1
  $ sed '1i\
  > repo2-1 at top
  > ' f > f.tmp
  $ mv f.tmp f
  $ hg ci -Aqmrepo2-1
  $ touch repo2-2
  $ hg pull -q ../repo1 -r 1
  $ hg merge -q
  $ hg ci -Aqmrepo2-2-merge
  $ touch repo2-3
  $ echo repo2-3 >> f
  $ hg ci -mrepo2-3
  $ hg log --template '{rev}:{node|short}  {desc|firstline}\n'
  4:2f0d178c469c  repo2-3
  3:9e6fb3e0b9da  repo2-2-merge
  2:8a58db72e69d  repo1-1
  1:c337dba826e7  repo2-1
  0:f093fec0529b  repo1-0
  $ cd ..

revisions from repo2 appear as appended / pulled to repo1

  $ hg -R union:repo1+repo2 log --template '{rev}:{node|short}  {desc|firstline}\n'
  5:2f0d178c469c  repo2-3
  4:9e6fb3e0b9da  repo2-2-merge
  3:c337dba826e7  repo2-1
  2:68c0685446a3  repo1-2
  1:8a58db72e69d  repo1-1
  0:f093fec0529b  repo1-0

manifest can be retrieved for revisions in both repos

  $ hg -R union:repo1+repo2 mani -r $tip1
  f
  repo1-0
  repo1-1
  repo1-2
  $ hg -R union:repo1+repo2 mani -r 4
  f
  repo1-0
  repo1-1
  repo2-1
  repo2-2

files can be retrieved form both repos

  $ hg -R repo1 cat repo1/f -r2
  repo1-0
  repo1-1
  repo1-2

  $ hg -R union:repo1+repo2 cat -r$tip1 repo1/f
  repo1-0
  repo1-1
  repo1-2

  $ hg -R union:repo1+repo2 cat -r4 $TESTTMP/repo1/f
  repo2-1 at top
  repo1-0
  repo1-1

files can be compared across repos

  $ hg -R union:repo1+repo2 diff -r$tip1 -rtip
  diff -r 68c0685446a3 -r 2f0d178c469c f
  --- a/f	Thu Jan 01 00:00:00 1970 +0000
  +++ b/f	Thu Jan 01 00:00:00 1970 +0000
  @@ -1,3 +1,4 @@
  +repo2-1 at top
   repo1-0
   repo1-1
  -repo1-2
  +repo2-3

heads from both repos are found correctly

  $ hg -R union:repo1+repo2 heads --template '{rev}:{node|short}  {desc|firstline}\n'
  5:2f0d178c469c  repo2-3
  2:68c0685446a3  repo1-2

revsets works across repos

  $ hg -R union:repo1+repo2 id -r "ancestor($tip1, 5)"
  8a58db72e69d

annotate works - an indication that linkrevs works

  $ hg --cwd repo1 -Runion:../repo2 annotate $TESTTMP/repo1/f -r tip
  3: repo2-1 at top
  0: repo1-0
  1: repo1-1
  5: repo2-3

union repos can be cloned ... and clones works correctly

  $ hg clone -U union:repo1+repo2 repo3
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 6 changesets with 11 changes to 6 files (+1 heads)
  new changesets f093fec0529b:2f0d178c469c (6 drafts)

  $ hg -R repo3 paths
  default = union:repo1+repo2

  $ hg -R repo3 verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  checked 6 changesets with 11 changes to 6 files

  $ hg -R repo3 heads --template '{rev}:{node|short}  {desc|firstline}\n'
  5:2f0d178c469c  repo2-3
  2:68c0685446a3  repo1-2

  $ hg -R repo3 log --template '{rev}:{node|short}  {desc|firstline}\n'
  5:2f0d178c469c  repo2-3
  4:9e6fb3e0b9da  repo2-2-merge
  3:c337dba826e7  repo2-1
  2:68c0685446a3  repo1-2
  1:8a58db72e69d  repo1-1
  0:f093fec0529b  repo1-0

union repos should use the correct rev number (issue5024)

  $ hg init a
  $ cd a
  $ echo a0 >> f
  $ hg ci -Aqm a0
  $ cd ..
  $ hg init b
  $ cd b
  $ echo b0 >> f
  $ hg ci -Aqm b0
  $ echo b1 >> f
  $ hg ci -qm b1
  $ cd ..

"hg files -v" to call fctx.size() -> fctx.iscensored()
  $ hg files -R union:b+a -r2 -v
           3   b/f