view tests/test-convert-svn-branches.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 svn svn-bindings

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

  $ svnadmin create svn-repo
  $ svnadmin load -q svn-repo < "$TESTDIR/svn/branches.svndump"

Convert trunk and branches

  $ cat > branchmap <<EOF
  > old3 newbranch
  > 
  > 
  > EOF
  $ hg convert --branchmap=branchmap --datesort -r 10 svn-repo A-hg
  initializing destination A-hg repository
  scanning source...
  sorting...
  converting...
  10 init projA
  9 hello
  8 branch trunk, remove c and dir
  7 change a
  6 change b
  5 move and update c
  4 move and update c
  3 change b again
  2 move to old2
  1 move back to old
  0 last change to a

Test template keywords

  $ hg -R A-hg log --template '{rev} {svnuuid}{svnpath}@{svnrev}\n'
  10 644ede6c-2b81-4367-9dc8-d786514f2cde/trunk@10
  9 644ede6c-2b81-4367-9dc8-d786514f2cde/branches/old@9
  8 644ede6c-2b81-4367-9dc8-d786514f2cde/branches/old2@8
  7 644ede6c-2b81-4367-9dc8-d786514f2cde/branches/old@7
  6 644ede6c-2b81-4367-9dc8-d786514f2cde/trunk@6
  5 644ede6c-2b81-4367-9dc8-d786514f2cde/branches/old@6
  4 644ede6c-2b81-4367-9dc8-d786514f2cde/branches/old@5
  3 644ede6c-2b81-4367-9dc8-d786514f2cde/trunk@4
  2 644ede6c-2b81-4367-9dc8-d786514f2cde/branches/old@3
  1 644ede6c-2b81-4367-9dc8-d786514f2cde/trunk@2
  0 644ede6c-2b81-4367-9dc8-d786514f2cde/trunk@1

Convert again

  $ hg convert --branchmap=branchmap --datesort svn-repo A-hg
  scanning source...
  sorting...
  converting...
  0 branch trunk@1 into old3

  $ cd A-hg
  $ hg log -G --template 'branch={branches} {rev} {desc|firstline} files: {files}\n'
  o  branch=newbranch 11 branch trunk@1 into old3 files:
  |
  | o  branch= 10 last change to a files: a
  | |
  | | o  branch=old 9 move back to old files:
  | | |
  | | o  branch=old2 8 move to old2 files:
  | | |
  | | o  branch=old 7 change b again files: b
  | | |
  | o |  branch= 6 move and update c files: b
  | | |
  | | o  branch=old 5 move and update c files: c
  | | |
  | | o  branch=old 4 change b files: b
  | | |
  | o |  branch= 3 change a files: a
  | | |
  | | o  branch=old 2 branch trunk, remove c and dir files: c
  | |/
  | o  branch= 1 hello files: a b c dir/e
  |/
  o  branch= 0 init projA files:
  

  $ hg branches
  newbranch                     11:a6d7cc050ad1
  default                       10:6e2b33404495
  old                            9:1b494af68c0b
  old2                           8:5be40b8dcbf6 (inactive)
  $ hg tags -q
  tip
  $ cd ..

Test hg failing to call itself

  $ HG=foobar hg convert svn-repo B-hg 2>&1 | grep abort
  abort: Mercurial failed to run itself, check hg executable is in PATH

Convert 'trunk' to branch other than 'default'

  $ cat > branchmap <<EOF
  > default hgtrunk
  > 
  > 
  > EOF
  $ hg convert --branchmap=branchmap --datesort -r 10 svn-repo C-hg
  initializing destination C-hg repository
  scanning source...
  sorting...
  converting...
  10 init projA
  9 hello
  8 branch trunk, remove c and dir
  7 change a
  6 change b
  5 move and update c
  4 move and update c
  3 change b again
  2 move to old2
  1 move back to old
  0 last change to a

  $ cd C-hg
  $ hg branches --template '{branch}\n'
  hgtrunk
  old
  old2
  $ cd ..