I probably have a rookie questions.
I have changed the persistence database from hsql to mysql, using the examples that come with JBM installation. I can see that Jboss uses the default 'fullsize' and I can verify that it is set to 200,000. Jboss created the needed tables in mysql and my application works fine.
The only thing that I don't understand is why Jboss is writing the messages to the database even when I don't reach 200,000 messages in the memory. I monitor mysql and can see the messages written to the jbm_msg tables from the beginning. I have set the JVM to 1024M and it doesn't take more than 200m.
I need a very fast messaging engine. I can suffer the loss of messages if the JVM falls so I want to work with the memory as much as possible. This behavior causes to a terrible performance issue.
Can anyone please advise ?