view tests/test-bheads.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.

  $ heads()
  > {
  >    hg heads --template '{rev}: {desc|firstline|strip} ({branches})\n' "$@"
  > }

  $ hg init a
  $ cd a
  $ echo 'root' >root
  $ hg add root
  $ hg commit -m "Adding root node"
  $ heads
  0: Adding root node ()
-------
  $ heads .
  0: Adding root node ()

=======

  $ echo 'a' >a
  $ hg add a
  $ hg branch a
  marked working directory as branch a
  (branches are permanent and global, did you want a bookmark?)
  $ hg commit -m "Adding a branch"
  $ heads
  1: Adding a branch (a)
  0: Adding root node ()
-------
  $ heads .
  1: Adding a branch (a)

=======

  $ hg update -C 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo 'b' >b
  $ hg add b
  $ hg branch b
  marked working directory as branch b
  (branches are permanent and global, did you want a bookmark?)
  $ hg commit -m "Adding b branch"
  $ heads
  2: Adding b branch (b)
  1: Adding a branch (a)
  0: Adding root node ()
-------
  $ heads .
  2: Adding b branch (b)

=======

  $ echo 'bh1' >bh1
  $ hg add bh1
  $ hg commit -m "Adding b branch head 1"
  $ heads
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
-------
  $ heads .
  3: Adding b branch head 1 (b)

=======

  $ hg update -C 2
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo 'bh2' >bh2
  $ hg add bh2
  $ hg commit -m "Adding b branch head 2"
  created new head
  $ heads
  4: Adding b branch head 2 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
  $ heads .
  4: Adding b branch head 2 (b)
  3: Adding b branch head 1 (b)

=======

  $ hg update -C 2
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo 'bh3' >bh3
  $ hg add bh3
  $ hg commit -m "Adding b branch head 3"
  created new head
  $ heads
  5: Adding b branch head 3 (b)
  4: Adding b branch head 2 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
-------
  $ heads .
  5: Adding b branch head 3 (b)
  4: Adding b branch head 2 (b)
  3: Adding b branch head 1 (b)

=======

  $ hg merge 4
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg commit -m "Merging b branch head 2 and b branch head 3"
  $ heads
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
-------
  $ heads .
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)

=======

  $ echo 'c' >c
  $ hg add c
  $ hg branch c
  marked working directory as branch c
  (branches are permanent and global, did you want a bookmark?)
  $ hg commit -m "Adding c branch"
  $ heads
  7: Adding c branch (c)
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
-------
  $ heads .
  7: Adding c branch (c)

=======

  $ heads -r 3 .
  no open branch heads found on branches c (started at 3)
  [1]
  $ heads -r 2 .
  7: Adding c branch (c)
-------
  $ hg update -C 4
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
-------
  $ heads -r 3 .
  3: Adding b branch head 1 (b)
-------
  $ heads -r 2 .
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
-------
  $ heads -r 7 .
  no open branch heads found on branches b (started at 7)
  [1]

=======

  $ for i in 0 1 2 3 4 5 6 7; do
  >     hg update -C "$i"
  >     heads
  >     echo '-------'
  >     heads .
  >     echo '-------'
  > done
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
  7: Adding c branch (c)
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
  -------
  0: Adding root node ()
  -------
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  7: Adding c branch (c)
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
  -------
  1: Adding a branch (a)
  -------
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  7: Adding c branch (c)
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
  -------
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  -------
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  7: Adding c branch (c)
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
  -------
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  -------
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  7: Adding c branch (c)
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
  -------
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  -------
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  7: Adding c branch (c)
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
  -------
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  -------
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  7: Adding c branch (c)
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
  -------
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  -------
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  7: Adding c branch (c)
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()
  -------
  7: Adding c branch (c)
  -------

=======

  $ for i in a b c z; do
  >     heads "$i"
  >     echo '-------'
  > done
  1: Adding a branch (a)
  -------
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  -------
  7: Adding c branch (c)
  -------
  abort: unknown revision 'z'!
  -------

=======

  $ heads 0 1 2 3 4 5 6 7
  7: Adding c branch (c)
  6: Merging b branch head 2 and b branch head 3 (b)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)
  0: Adding root node ()

Topological heads:

  $ heads -t
  7: Adding c branch (c)
  3: Adding b branch head 1 (b)
  1: Adding a branch (a)

  $ cd ..
______________

"created new head" message tests

  $ hg init newheadmsg
  $ cd newheadmsg

Init: no msg

  $ echo 1 > a
  $ hg ci -Am "a0: Initial root"
  adding a
  $ echo 2 >> a
  $ hg ci -m "a1 (HN)"

  $ hg branch b
  marked working directory as branch b
  (branches are permanent and global, did you want a bookmark?)
  $ echo 1 > b
  $ hg ci -Am "b2: Initial root for branch b"
  adding b
  $ echo 2 >> b
  $ hg ci -m "b3 (HN)"

Case NN: msg

  $ hg up -q null
  $ hg branch -f b
  marked working directory as branch b
  (branches are permanent and global, did you want a bookmark?)
  $ echo 1 > bb
  $ hg ci -Am "b4 (NN): new topo root for branch b"
  adding bb
  created new head

Case HN: no msg

  $ echo 2 >> bb
  $ hg ci -m "b5 (HN)"

Case BN: msg

  $ hg branch -f default
  marked working directory as branch default
  (branches are permanent and global, did you want a bookmark?)
  $ echo 1 > aa
  $ hg ci -Am "a6 (BN): new branch root"
  adding aa
  created new head

Case CN: msg

  $ hg up -q 4
  $ echo 3 >> bbb
  $ hg ci -Am "b7 (CN): regular new head"
  adding bbb
  created new head

Case BB: msg

  $ hg up -q 4
  $ hg merge -q 3
  $ hg branch -f default
  marked working directory as branch default
  (branches are permanent and global, did you want a bookmark?)
  $ hg ci -m "a8 (BB): weird new branch root"
  created new head

Case CB: msg

  $ hg up -q 4
  $ hg merge -q 1
  $ hg ci -m "b9 (CB): new head from branch merge"
  created new head

Case HB: no msg

  $ hg up -q 7
  $ hg merge -q 6
  $ hg ci -m "b10 (HB): continuing head from branch merge"

Case CC: msg

  $ hg up -q 4
  $ hg merge -q 2
  $ hg ci -m "b11 (CC): new head from merge"
  created new head

Case CH: no msg

  $ hg up -q 2
  $ hg merge -q 10
  $ hg ci -m "b12 (CH): continuing head from merge"

Case HH: no msg

  $ hg merge -q 3
  $ hg ci -m "b12 (HH): merging two heads"