revsets: huge speedups for fromsvn and svnrev I have a hgsubversion repo that contains over 300,000 commits. In that repo, this patch improves performance as follows: hg --time log -r 'first(fromsvn())' Before: 40.3 sec After: 0.8 sec hg --time log -r 'svnrev(350000)' Before: 40.3 sec After: 0.1 sec Note: the performance of these revset implementations is very sensitive to doing as little work as possible per line of the rev_map file. I originally attempted to hide the file format details by hoisting the parsing of each line up into RevMap.readmapfile, but the current less abstract code is dramatically (10x or more) faster. If the revmap file is missing, we error out and print a message describing what to do.

#!/bin/sh

mkdir temp
cd temp
svnadmin create repo
svn co file://`pwd`/repo wc
export REPO=file://`pwd`/repo
cd wc
mkdir branches trunk tags
svn add *
svn ci -m 'Empty dirs.'

echo 'file: alpha' > trunk/alpha
svn add trunk/alpha
svn ci -m 'Add alpha'
svn up

echo 'Data of beta' > trunk/beta
svn add trunk/beta
svn ci -m 'Add beta'
svn up
cd ..

svn cp -m 'tagging r3' $REPO/trunk@3 $REPO/tags/tag_r3
svn cp -m 'tag from a tag' $REPO/tags/tag_r3 $REPO/tags/copied_tag
svn mv -m 'rename a tag' $REPO/tags/copied_tag $REPO/tags/other_tag_r3
cd ..
svnadmin dump temp/repo > rename_tag_test.svndump
echo
echo 'Complete.'
echo 'You probably want to clean up temp now.'
echo 'Dump in renametagdir.svndump'
exit 0