From DeveloperWorks, The WebSphere Contrarian: Are you sure you want to reorg that messaging engine database?

The standard practice for database administration is to periodically
check on the database and table organization to insure optimal performance —
but do these standard practices apply to a database used for JMS persistent
message storage with IBM WebSphere Application Server? (IBM WebSphere Developer Technical Journal)

An interesting article about your messaging engines databases and how they are structured.