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)
$ "$TESTDIR/hghave" svn svn-bindings || exit 80
$ echo "[extensions]" >> $HGRCPATH
$ echo "convert = " >> $HGRCPATH
$ echo "mq = " >> $HGRCPATH
$ SVNREPOPATH=`pwd`/svn-repo
#if windows
$ SVNREPOURL=file:///`python -c "import urllib, sys; sys.stdout.write(urllib.quote(sys.argv[1]))" "$SVNREPOPATH"`
#else
$ SVNREPOURL=file://`python -c "import urllib, sys; sys.stdout.write(urllib.quote(sys.argv[1]))" "$SVNREPOPATH"`
#endif
$ svnadmin create "$SVNREPOPATH"
$ cat > "$SVNREPOPATH"/hooks/pre-revprop-change <<EOF
> #!/bin/sh
>
> REPOS="$1"
> REV="$2"
> USER="$3"
> PROPNAME="$4"
> ACTION="$5"
>
> if [ "$ACTION" = "M" -a "$PROPNAME" = "svn:log" ]; then exit 0; fi
> if [ "$ACTION" = "A" -a "$PROPNAME" = "hg:convert-branch" ]; then exit 0; fi
> if [ "$ACTION" = "A" -a "$PROPNAME" = "hg:convert-rev" ]; then exit 0; fi
>
> echo "Changing prohibited revision property" >&2
> exit 1
> EOF
$ chmod +x "$SVNREPOPATH"/hooks/pre-revprop-change
$ svn co "$SVNREPOURL" "$SVNREPOPATH"-wc
Checked out revision 0.
$ cd "$SVNREPOPATH"-wc
$ echo a > a
$ svn add a
A a
$ svn ci -m'added a' a
Adding a
Transmitting file data .
Committed revision 1.
$ cd ..
initial roundtrip
$ hg convert -s svn -d hg "$SVNREPOPATH"-wc "$SVNREPOPATH"-hg | grep -v initializing
scanning source...
sorting...
converting...
0 added a
$ hg convert -s hg -d svn "$SVNREPOPATH"-hg "$SVNREPOPATH"-wc
scanning source...
sorting...
converting...
second roundtrip should do nothing
$ hg convert -s svn -d hg "$SVNREPOPATH"-wc "$SVNREPOPATH"-hg
scanning source...
sorting...
converting...
$ hg convert -s hg -d svn "$SVNREPOPATH"-hg "$SVNREPOPATH"-wc
scanning source...
sorting...
converting...
new hg rev
$ hg clone "$SVNREPOPATH"-hg "$SVNREPOPATH"-work
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd "$SVNREPOPATH"-work
$ echo b > b
$ hg add b
$ hg ci -mb
adding an empty revision
$ hg qnew -m emtpy empty
$ hg qfinish -a
$ cd ..
echo hg to svn
$ hg --cwd "$SVNREPOPATH"-hg pull -q "$SVNREPOPATH"-work
$ hg convert -s hg -d svn "$SVNREPOPATH"-hg "$SVNREPOPATH"-wc
scanning source...
sorting...
converting...
1 b
0 emtpy
svn back to hg should do nothing
$ hg convert -s svn -d hg "$SVNREPOPATH"-wc "$SVNREPOPATH"-hg
scanning source...
sorting...
converting...
hg back to svn should do nothing
$ hg convert -s hg -d svn "$SVNREPOPATH"-hg "$SVNREPOPATH"-wc
scanning source...
sorting...
converting...