view tests/test-convert-svn-branches.t @ 16120:47ee41fcf42b

largefiles: optimize update speed by only updating changed largefiles

Historically, during 'hg update', every largefile in the working copy was
hashed (which is a very expensive operation on big files) and any
largefiles that did not have a hash that matched their standin were
updated.

This patch optimizes 'hg update' by keeping track of what standins have
changed between the old and new revisions, and only updating the largefiles
that have changed.  This saves a lot of time by avoiding the unecessary
calculation of a list of sha1 hashes for big files.

With this patch, the time 'hg update' takes to complete is a function of
how many largefiles need to be updated and what their size is.

Performance tests on a repository with about 80 largefiles ranging from
a few MB to about 97 MB are shown below.  The tests show how long it takes
to run 'hg update' with no changes actually being updated.

Mercurial 2.1 release:

$ time hg update
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
getting changed largefiles
0 largefiles updated, 0 removed

real    0m10.045s
user    0m9.367s
sys    0m0.674s

With this patch:

$ time hg update
0 files updated, 0 files merged, 0 files removed, 0 files unresolved

real    0m0.965s
user    0m0.845s
sys    0m0.115s

The same repsoitory, without the largefiles extension enabled:

$ time hg update
0 files updated, 0 files merged, 0 files removed, 0 files unresolved

real    0m0.799s
user    0m0.684s
sys    0m0.111s

So before the patch, 'hg update' with no changes was approximately 9.25s
slower with largefiles enabled.  With this patch, it is approximately 0.165s
slower.

  $ "$TESTDIR/hghave" svn svn-bindings || exit 80

  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > convert = 
  > graphlog =
  > 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 glog --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                            9:93c4b0f99529
  old2                           8:b52884d7bead (inactive)
  $ hg tags -q
  tip
  $ cd ..

Test hg failing to call itself

  $ HG=foobar hg convert svn-repo B-hg
  * (glob)
  initializing destination B-hg repository
  abort: Mercurial failed to run itself, check hg executable is in PATH
  [255]