Partial metadata rebuilding For highly active subversion repositories, it can be excruciatingly slow to pull updates one at a time from subversion. One way around this is to setup another mercurial repo that pulls new commits from svn periodicly (say every 5 minutes). When you want to update your repository, you can pull commits from this mercurial repository via native mercurial protocols, which will be much faster than pulling directly from svn. Unfortunately, your metadata will be out of date after doing so. Highly active repositories also tend to be very large, which means that it takes a long time to rebuild your metadata from scratch. To address this, this adds support to do a partial rebuild on the metadata by processing only revisions that have been added to the repository after the last revision we processed. With the rev map 1k revisions (~2 days) behind tip updatemeta is dramatically faster than rebuild meta: $ hg --time svn updatemeta Time: real 0.570 secs (user 0.480+0.000 sys 0.060+0.000) $ hg --time svn rebuildmeta Time: real 129.160 secs (user 128.570+0.000 sys 0.320+0.000)

#!/bin/sh
#
# Generate mergeexternals.svndump
#

mkdir temp
cd temp

mkdir project-orig
cd project-orig
mkdir trunk
mkdir branches
cd ..

svnadmin create testrepo
svnurl=file://`pwd`/testrepo
svn import project-orig $svnurl -m "init project"

svn co $svnurl project
cd project/trunk
mkdir d1
echo a > d1/a
mkdir d2
echo b > d2/b
mkdir -p common/ext
echo c > common/ext/c
svn add d1 d2 common
svn ci -m addfiles
svn up
svn propset svn:externals '^/trunk/common/ext ext' d1
svn propset svn:externals '^/trunk/common/ext ext' d2
svn ci -m addexternals
cd ..
svn up
svn cp trunk branches/branch
cd branches
svn ci -m addbranch
cd branch
mkdir d3
echo d > d3/d
svn add d3
svn propset svn:externals '^/trunk/common/ext ext3' d3
svn ci -m touchbranch
cd ../../trunk
svn merge '^/branches/branch'
svn up
svn ci -m 'merge'
cd ../..

svnadmin dump testrepo > ../mergeexternals.svndump