Toubleshooting sharepoint timer jobs for alerts

Find out content db for site having issues

Find out timer job service executing server using,
select * from timerlock

Find other info
select * from eventcache where eventdata is not null
select * from eventlog where ListID='xxx'
select * from eventcache order by EventTime DESC

http://sharepointalert.info/2009/11/troubleshooting-sharepoint-alerts-timer-jobs/