Using Advanced Queuing with XA

You must specify "Objects=T" in the xa_open string if you want to use the AQ OCI interface. This forces XA to initialize the client-side cache in Objects mode. You do not need to do this if you plan to use AQ through PL/SQL wrappers from OCI or Pro*C. The LOB memory management concepts from the Pro* documentation are not relevant for AQ raw messages because AQ provides a simple RAW buffer abstraction (although they are stored as LOBs).

When using the AQ navigation option, you must reset the dequeue position by using the FIRST_MESSAGE if you want to continue dequeuing between services (such as xa_start and xa_end boundaries). This is because XA cancels the cursor fetch state after an xa_end. If you do not reset, you will get an error message stating that the navigation is used out of sequence (ORA-25237).