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
# inspired by Python r62868

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 'btt'

echo a > trunk/a
svn add trunk/a
svn ci -m 'Add file.'
svn up

svn cp trunk branches/badname
svn ci -m 'Branch to be renamed.'
svn up

svn cp trunk branches/feature
svn ci -m 'Branch to be unnamed.'
svn up

cd ../..
svnadmin dump temp/repo > branchmap.svndump
echo
echo 'Complete.'
echo 'You probably want to clean up temp now.'
echo 'Dump in branchmap.svndump'
exit 0