I encountered one error scenario in PS5. Had developed a process in PS5. The process shows all interaction as successful but finally the transaction was getting rolled back. The em console shows the process instance as errored out but no errors were shown.
The process involves multiple DB interactions was triggered by polling a table.
BPEL process instance "1040126" completed
The transaction was rolled back. The work performed for bpel instance "1040126" was rolled back, but the audit trail has been saved for this instance.If this is a sync request, please resubmit the request from the client. If it is an async request, please recover from the recovery console by resubmitting the invoke message.
As always the only option was to go behind the scenes ,enable logging to TRACE-FINEST for oracle.soa.adapter and monitor the logs.
The issue was due to a CONSTRAINT in the table which was being violated by the polling process which was inserting a value not supported by constraint for that column.
Error from Log File
012-11-08T02:43:31.005-06:00] [fmwDirect-directi02] [ERROR]  [oracle.soa.adapter] [tid: Workmanager: , Version: 0, Scheduled=false, Started=false, Wait time: 0 ms\n] [userId: <anonymous>] [ecid: 8a5d5fb1e9381abe:13601ac5:13adc7cdc79:-8000-000000000001747c,0] [APP: soa-infra] Database Adapter TestProcess <oracle.tip.adapter.db.InboundWork handleException> Encountered a fatal exception while polling. Will continue polling but with minimal logging. Please investigate the fault and manually stop polling from the console if in development and this appears to be a modeling mistake. BINDING.JCA-11624[[
DBActivationSpec Polling Exception.
Query name: [triggerTransactionSelect], Descriptor name: [triggerTransaction.Transaction]. Polling the database for events failed on this iteration.
Caused by java.sql.BatchUpdateException: ORA-02290: check constraint (STATUS) violated
This exception is considered not retriable, likely due to a modelling mistake. To classify it as retriable instead add property nonRetriableErrorCodes with value "-2290" to your deployment descriptor (i.e. weblogic-ra.xml). This polling process will shut down, unless the fault is related to processing a particular row, in which case polling will continue but the row will be rejected (faulted).
The DB adapter will throw an error while interacting with the DB layer. There will be some constraint errors which may not be propagated through the Toplink layer, there by not showing up in the console. But logs will not hide them,and will help you to debug the issue.