Advanced Queuing - Oracle

Messaging Gateway Questions
How do I tell if messages are being propagated or moved to the
exception queue?
The PROPAGATED_MSGS field of the MGW_SUBSCRIBERS view indicates how many
messages have been successfully propagated. The EXCEPTIONQ_MSGS field
indicates how many messages have been moved to the exception queue. Both these
fields are reset to zero when the MGW agent is started.
When are messages moved to the propagation job exception queue?
If a MGW subscriber has been configured with an exception queue, the MGW agent
will move messages to that exception queue the first time the MGW agent
encounters a propagation failure due to a message conversion failure. A message
conversion failure is indicated by oracle.mgw.common.MessageException in
the MGW log file.
How do I recover from a message conversion failure? How do I continue
processing when oracle.mgw.common.MessageException occurs?
If a message conversion failure occurs,
oracle.mgw.common.MessageException is be logged to the MGW log file. If
this occurs, the MGW agent probably cannot propagate the message causing the
failure, and the propagation job will eventually be disabled.
If the log file indicates that the failure is due to an exception being raised in a
transformation function used for an AQ dequeue (outbound propagation) or AQ
enqueue (inbound propagation), verify that the transformation function is correct.
The MGW subscriber can be configured with a propagation exception queue. If a
message conversion failure occurs, the MGW agent moves that message to the
exception queue and then continues processing the propagation job.
How do I recover a failed propagation job?
If a propagation job runs into failures during processing, the MGW agent retries up
to 16 times in an exponential backoff scheme before disabling the job.
To recover from a failed propagation job, do the following:
1. Look at the MGW log file to determine the nature of the failure and correct the
problem. For a message conversion failure, the MGW subscriber may need to be
configured with an exception queue.
2. Call dbms_mgwadm.reset_subscriber to reset the subscriber state. The
MGW agent will attempt to recover the failed job and retry the propagation.
6-12 Oracle9i Application Developer’s Guide - Advanced Queuing