view tests/test-rename-after-merge.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.

Issue746: renaming files brought by the second parent of a merge was
broken.

Create source repository:

  $ hg init t
  $ cd t
  $ echo a > a
  $ hg ci -Am a
  adding a
  $ cd ..

Fork source repository:

  $ hg clone t t2
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd t2
  $ echo b > b
  $ hg ci -Am b
  adding b

Update source repository:

  $ cd ../t
  $ echo a >> a
  $ hg ci -m a2

Merge repositories:

  $ hg pull ../t2
  pulling from ../t2
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files (+1 heads)
  (run 'hg heads' to see heads, 'hg merge' to merge)

  $ hg merge
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ hg st
  M b

Rename b as c:

  $ hg mv b c
  $ hg st
  A c
  R b

Rename back c as b:

  $ hg mv c b
  $ hg st
  M b

  $ cd ..

Issue 1476: renaming a first parent file into another first parent
file while none of them belong to the second parent was broken

  $ hg init repo1476
  $ cd repo1476
  $ echo a > a
  $ hg ci -Am adda
  adding a
  $ echo b1 > b1
  $ echo b2 > b2
  $ hg ci -Am changea
  adding b1
  adding b2
  $ hg up -C 0
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ echo c1 > c1
  $ echo c2 > c2
  $ hg ci -Am addcandd
  adding c1
  adding c2
  created new head

Merge heads:

  $ hg merge
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ hg mv -Af c1 c2

Commit issue 1476:

  $ hg ci -m merge

  $ hg log -r tip -C -v | grep copies
  copies:      c2 (c1)

  $ hg rollback
  repository tip rolled back to revision 2 (undo commit)
  working directory now based on revisions 2 and 1

  $ hg up -C .
  2 files updated, 0 files merged, 2 files removed, 0 files unresolved

Merge heads again:

  $ hg merge
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ hg mv -Af b1 b2

Commit issue 1476 with a rename on the other side:

  $ hg ci -m merge

  $ hg log -r tip -C -v | grep copies
  copies:      b2 (b1)