IMPORTANT - DIRECT MODIFICATION OF ANY SHAREPOINT DATABASE IS UNSUPPORTED.  This doesn't mean you can't peak though.

Important Tables I have found usful for troubleshooting.  I will publish as I define more.

Contentdb

• ImmedSubscriptions / SchedSubscriptions table  - Entry is made when an alert is fired.  Good place to check when alerts are not working.
• Eventcache - Subscriptions not processed - select * from eventcache where EventData is not null
• EventLog - Subscriptions Processed - select * from eventlog where ListID = 'xxx'

Configdb

TSQL Commands