Just some findings...
When we have more then one classification, the first call to DBMessageStoreImpl.redeliver passes without error, but the second call will throw an SQLException when con.setTransactionIsolation(Connection.TRANSACTION_READ_UNCOMMITTED); is invoked.
Commenting out the setting of the isolation level seems to work but not really an exceptable solution as we don't know why this is happening.
We are using the J2eeConnectionManager.
I'll post back if with any new findings.
Some info about postgres and its transaction isolation levels:
"In postgres, you can use all four possible transaction isolation
levels. Internally, there are only two distinct isolation levels, which
correspond to the
levels Read Committed and Serializable. When you select the level Read
Uncommitted you actually get Read Committed, and when you select
Repeatable Read you really get Serializable, so the actual isolation
level may be stricter than what you select."
Daniel, create a JIRA for this so we don't lose it.