I'm just getting started with Sonar 1.1 on an Oracle 10g database. I plugged it into cruise control for about a dozen different projects and within a day I noticed that the Sonar application got stuck "analysing" a build from more than 24 hours ago and the backlog of non-analysed build grew to over 20. I tried turning on INFO logging and restarting the process but found nothing informative in the logs.
Anyway, I also monitored some of Sonar's activity in the Oracle database and found a query against a very large table that was being executed many times and was not supported by any index. After adding an index on RULE_FAILURE_PARAMS.RULE_FAILURE_ID the sonar application quickly caught up on its backlog.
Clearly the size of the RULE_FAILURE_PARAMS table indicates some rules issues in our code

but this is all part of the process towards fixing that.
So, I just wanted to offer this suggestion for a patch / workaround if anyone else gets stuck with a long backlog of un-analysed builds.