Is is safe to use HSQLDB for production? (JBoss AS5.1)

Question

The JBoss developers warn against the use of HSQLDB as a persistent storage (see JBoss wiki). I am confused though, because HSQLDB appears to be used heavily in production.

Especially, the above mentioned page seems to warn against the use of HSQLDB entirely and not against the use in conjunction with JBoss.

Is it still not recommendable to use HSQLDB in JBoss (particularly, the bundled default datasource in Community JBoss 5.1)?

*:We plan to use it in in-memory mode.

Answer 1

If your own link doesn't convince you, then consider that using it in in-memory mode can lead to undesirable effects when JMS queues get backed up -- JBoss will start trying to persist the messages to the backing store to free heap space, but that won't actually help. Soon, you're spinning in GC or throwing OOM exceptions.