How to upgrade SVN from 1.7 to 1.9?

Question

I recently upgraded my Subversion client from version 1.7.5 to 1.8.3 and from that time on I experience hangs when executing multiple 'svn log' commands in a short amount of time. The "hanging" svn process consumes all CPU cycles it gets but never finishes.

I can reproduce the problem using the following shell script (on Windows using Cygwin):

#!/bin/bash
ROOT="http://example.com/svn/trunk"
for DIR in $(svn ls "${ROOT}" | head -n 4); do
 svn log -v -l 5 "${ROOT}/${DIR}" 2>&1 | head -n 100 > /dev/null
done

In my environment I need at least 4 svn processes to achieve the faulty behavior. The hang only occurs if the output is truncated using the head command (but it can be redirected to a normal file instead of /dev/null which then contains the expected log messages).

Answer 1

If you are using a particular SVN distribution take a look at the docs of that distribution.

If you are building SVN yourself, see (https://subversion.apache.org/docs/release-notes/1.9.html ): "[...] Subversion 1.9 servers can read and write to repositories created by earlier versions. To upgrade an existing server installation, just install the newest libraries and binaries on top of the older ones."

Don't forget to backup your repositories and server files before the upgrade though, to be sure that you have a backup at hand, if something goes wrong.

For your clients it's more or less the same (note that you don't need to have clients and servers running the same version --- you can also upgrade the client to 1.9 and keep the server at 1.7.8 or the other way around). Make sure their working directories are not locked (aka: run svn cleanup), upgrade the client to 1.9 and then upgrade the working directories (svn upgrade http://svnbook.red-bean.com/en/1.8/svn.ref.svn.c.upgrade.html ).