This is typically caused when a destination has lots of persistent messages in the database and the server needs to load them into memory when the destination is deployed.
Are these the JBM tables in the database? Is it possible to know which destination is causing the problem?
This is happening in a dev environment, is it okay to delete them?
What is the recommended approach to handling the messages in the database?
Yes, these are the JBM tables in the database.
Once the server has started, you can go to the JMX/web console under the "jboss.messaging.destination" category. Each destination has messages counters and the ability to remove messages from the destination.
If you have no problem with loosing those messages in the Dev environment, then feel free to remove them.