Quartz not picking up jobs with no errors

Question

Hi,

We're running Quartz 1.8.3 on JBoss 4.2.3 . The Quartz instance is configured to store job in Sybase with a no-tx datasource.

I'm currently having with Quartz not running any jobs at all, and no errors are being picked up from the logs. So far, I've confirmed the following:

• Adding a new trigger/job is working fine (rows added to database correctly)
• Manually triggering a job is OK, but the manual trigger stays in the database without firing, leaving something like 'MANUAL_TRIGGER'/'MT_6h9r743fta2mb' in the database.
• Debugging shows QuartzSchedulerThread's run() and isCandidateNewTimeEarlierWithinReason() is never called

Now I'm lost as to where to poke/explore further to find the root cause of the problem.

Any suggestions are appreciated!

Thanks in advance.