Ryan Hochstetler [http://community.jboss.org/people/ryanhos] created the 
discussion

"Re: message passing through underlying db"

To view the discussion, visit: http://community.jboss.org/message/594564#594564

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Tim,

If you really have three JBoss Messaging instances pointed at the same exact 
database tables, I think this is considered an "out of spec" configuration.  
Each independent, non-clustered JBoss Messaging instance requires sole access 
to the underlying database tables.  (Clustered JBM's understand that they share 
the tables with other nodes and are configured with a unique identifier that 
prevents them from seeing messages from other nodes).  If you are going to run 
three or four independent JBM instances, you might consider giving each JBM 
instance it's own login credentials and create all of the messaging tables 
under the default schema for each credential.

You cannot pass messages with the DB, to my knowledge.  JBM doesn't appear to 
requery the DB.  It just assumes that since it is the only thing modifying 
those tables, the tables are consistent with its internal state, where it keeps 
all messages it is currently processing.  For the most part, it issues INSERTs 
and DELETEs, rarely SELECTs, except at boot to get the initial working set, or 
when you've exceeded a queue's FullSize.  DB message passing saves less work 
than you think if you mentally draw the sequence diagram for each scenario.

Why not just have Nodes 1 through 3 send messages directly to Node 4?  Instead 
of looking-up the ConnectionFactory on the local JBoss, look-up the 
ConnectionFactory on JBoss 4, and the rest of your code should function as 
expected.
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