obsolete: order of magnitude speedup in _computebumpedset
Reminder: a changeset is said "bumped" if it tries to obsolete a immutable
changeset.
The previous algorithm for computing bumped changeset was:
1) Get all public changesets
2) Find all they successors
3) Search for stuff that are eligible for being "bumped"
(mutable and non obsolete)
The entry size of this algorithm is `O(len(public))` which is mostly the same as
`O(len(repo))`. Even this this approach mean fewer obsolescence marker are
traveled, this is not very scalable.
The new algorithm is:
1) For each potential bumped changesets (non obsolete mutable)
2) iterate over precursors
3) if a precursors is public. changeset is bumped
We travel more obsolescence marker, but the entry size is much smaller since
the amount of potential bumped should remains mostly stable with time `O(1)`.
On some confidential gigantic repo this move bumped computation from 15.19s to
0.46s (×33 speedup…). On "smaller" repo (mercurial, cubicweb's review) no
significant gain were seen. The additional traversal of obsolescence marker is
probably probably counter balance the advantage of it.
Other optimisation could be done in the future (eg: sharing precursors cache
for divergence detection)
Set vars:
$ CONTRIBDIR="$TESTDIR/../contrib"
Prepare repo-a:
$ hg init repo-a
$ cd repo-a
$ echo this is file a > a
$ hg add a
$ hg commit -m first
$ echo adding to file a >> a
$ hg commit -m second
$ echo adding more to file a >> a
$ hg commit -m third
$ hg verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
1 files, 3 changesets, 3 total revisions
Dumping revlog of file a to stdout:
$ python "$CONTRIBDIR/dumprevlog" .hg/store/data/a.i
file: .hg/store/data/a.i
node: 183d2312b35066fb6b3b449b84efc370d50993d0
linkrev: 0
parents: 0000000000000000000000000000000000000000 0000000000000000000000000000000000000000
length: 15
-start-
this is file a
-end-
node: b1047953b6e6b633c0d8197eaa5116fbdfd3095b
linkrev: 1
parents: 183d2312b35066fb6b3b449b84efc370d50993d0 0000000000000000000000000000000000000000
length: 32
-start-
this is file a
adding to file a
-end-
node: 8c4fd1f7129b8cdec6c7f58bf48fb5237a4030c1
linkrev: 2
parents: b1047953b6e6b633c0d8197eaa5116fbdfd3095b 0000000000000000000000000000000000000000
length: 54
-start-
this is file a
adding to file a
adding more to file a
-end-
Dump all revlogs to file repo.dump:
$ find .hg/store -name "*.i" | sort | xargs python "$CONTRIBDIR/dumprevlog" > ../repo.dump
$ cd ..
Undumping into repo-b:
$ hg init repo-b
$ cd repo-b
$ python "$CONTRIBDIR/undumprevlog" < ../repo.dump
.hg/store/00changelog.i
.hg/store/00manifest.i
.hg/store/data/a.i
$ cd ..
Rebuild fncache with clone --pull:
$ hg clone --pull -U repo-b repo-c
requesting all changes
adding changesets
adding manifests
adding file changes
added 3 changesets with 3 changes to 1 files
Verify:
$ hg -R repo-c verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
1 files, 3 changesets, 3 total revisions
Compare repos:
$ hg -R repo-c incoming repo-a
comparing with repo-a
searching for changes
no changes found
[1]
$ hg -R repo-a incoming repo-c
comparing with repo-c
searching for changes
no changes found
[1]
Test simplemerge command:
$ cp "$CONTRIBDIR/simplemerge" .
$ echo base > base
$ echo local > local
$ cat base >> local
$ cp local orig
$ cat base > other
$ echo other >> other
changing local directly
$ python simplemerge local base other && echo "merge succeeded"
merge succeeded
$ cat local
local
base
other
$ cp orig local
printing to stdout
$ python simplemerge -p local base other
local
base
other
local:
$ cat local
local
base
conflicts
$ cp base conflict-local
$ cp other conflict-other
$ echo not other >> conflict-local
$ echo end >> conflict-local
$ echo end >> conflict-other
$ python simplemerge -p conflict-local base conflict-other
base
<<<<<<< conflict-local
not other
=======
other
>>>>>>> conflict-other
end
warning: conflicts during merge.
[1]
--no-minimal
$ python simplemerge -p --no-minimal conflict-local base conflict-other
base
<<<<<<< conflict-local
not other
end
=======
other
end
>>>>>>> conflict-other
warning: conflicts during merge.
[1]
1 label
$ python simplemerge -p -L foo conflict-local base conflict-other
base
<<<<<<< foo
not other
=======
other
>>>>>>> conflict-other
end
warning: conflicts during merge.
[1]
2 labels
$ python simplemerge -p -L foo -L bar conflict-local base conflict-other
base
<<<<<<< foo
not other
=======
other
>>>>>>> bar
end
warning: conflicts during merge.
[1]
too many labels
$ python simplemerge -p -L foo -L bar -L baz conflict-local base conflict-other
abort: can only specify two labels.
[255]
binary file
$ python -c "f = file('binary-local', 'w'); f.write('\x00'); f.close()"
$ cat orig >> binary-local
$ python simplemerge -p binary-local base other
warning: binary-local looks like a binary file.
[1]
binary file --text
$ python simplemerge -a -p binary-local base other 2>&1
warning: binary-local looks like a binary file.
\x00local (esc)
base
other
help
$ python simplemerge --help
simplemerge [OPTS] LOCAL BASE OTHER
Simple three-way file merge utility with a minimal feature set.
Apply to LOCAL the changes necessary to go from BASE to OTHER.
By default, LOCAL is overwritten with the results of this operation.
options:
-L --label labels to use on conflict markers
-a --text treat all files as text
-p --print print results instead of overwriting LOCAL
--no-minimal do not try to minimize conflict regions
-h --help display help and exit
-q --quiet suppress output
wrong number of arguments
$ python simplemerge
simplemerge: wrong number of arguments
simplemerge [OPTS] LOCAL BASE OTHER
Simple three-way file merge utility with a minimal feature set.
Apply to LOCAL the changes necessary to go from BASE to OTHER.
By default, LOCAL is overwritten with the results of this operation.
options:
-L --label labels to use on conflict markers
-a --text treat all files as text
-p --print print results instead of overwriting LOCAL
--no-minimal do not try to minimize conflict regions
-h --help display help and exit
-q --quiet suppress output
[1]
bad option
$ python simplemerge --foo -p local base other
simplemerge: option --foo not recognized
simplemerge [OPTS] LOCAL BASE OTHER
Simple three-way file merge utility with a minimal feature set.
Apply to LOCAL the changes necessary to go from BASE to OTHER.
By default, LOCAL is overwritten with the results of this operation.
options:
-L --label labels to use on conflict markers
-a --text treat all files as text
-p --print print results instead of overwriting LOCAL
--no-minimal do not try to minimize conflict regions
-h --help display help and exit
-q --quiet suppress output
[1]