Cruisecontrol hangs when checking SVN for modifications

Question

Since migrating a Cruisecontrol build server to a new machine, it sometimes hangs during the "modificationset" stage of the build cycle (it is configured to check for modifications every 15 minutes). Cruisecontrol itself stays responsive, only the build does not progress.

There is no significant load on the CPU when this happens, and I've seen it stay in this state for an hour or more, though it seems to break out of this state eventually. There doesn't seem to be a pattern to which projects it happens to. The hardware is brand new, and I have run a memtest with no problems.

This is the system configuration:

• Ubuntu 9.04 server, amd64, fully upgraded
• svn version 1.5.4 (r33841) - the most recent version apt-get will install
• Sun JRE 64 bit build 1.6.0_16-b01 - again, most recent version
• CruiseControl 2.7.3 (not the most recent)

This is how my modificationsets look like

<modificationset quietperiod="10">
    <veto><!-- there are several of these -->
        <triggers>
            <svn LocalWorkingCopy="${checkout_dir}/base" />
        </triggers>
        <buildstatus logdir="${log_dir}/base" />
    </veto>
    <timebuild time="2330" />
    <svn LocalWorkingCopy="${checkout_dir}/${project.name}" />
</modificationset>

So what could be done here?

Edit: Here's a excerpt from the cruisecontrol log file, showing projectA hanging at 16:07 (it is still hanging now at 17:48)

2009-10-27 16:07:55,096 [Thread-38860] INFO  Project          - Project projectA:  bootstrapping
2009-10-27 16:07:55,096 [Thread-38860] INFO  ProjectController - projectA Controller: build progress event: bootstrapping
2009-10-27 16:07:55,262 [Thread-38862] INFO  ScriptRunner     - Buildfile: work/build-cruisecontrol.xml
2009-10-27 16:07:59,230 [Thread-38860] INFO  AntBootstrapper  - Bootstrap successful.
2009-10-27 16:07:59,230 [Thread-38860] INFO  Project          - Project projectA:  checking for modifications
2009-10-27 16:07:59,230 [Thread-38860] INFO  ProjectController - projectA Controller: build progress event: checking for modifications
2009-10-27 16:11:14,954 [Project projectB thread] INFO  Project          - Project projectB:  in build queue

Answer 1

Another idea. You could always start the CruiseControl JVM in debug mode. And whenever it hangs, connect to it using some IDE, e.g. Eclipse. And then you could all the threads of the CC application, and pause some of them and see what are they busy with.