Advanced Queuing - Oracle

General Features of JMS
backed_order topic. Specifying the retention as TRUE for the shipping queues and
specifying the order number in the correlation field of the message, SQL queries can
be written to determine the wait time for orders in the shipping application.
For simplicity, we will only analyze orders that have already been processed. The
processing time for an order in the shipping application is the difference between
the enqueue time in the WS_bookedorders_topic and the enqueue time in the
WS_shipped_orders_topic.
SELECT SUM(SO.enq_time - BO.enq_time) / count (*) AVG_PRCS_TIME
FROM WS.AQ$WS_orders_pr_mqtab BO , WS.AQ$WS_orders_mqtab SO
WHERE SO.msg_state = ’PROCESSED’ and BO.msg_state = ’PROCESSED’
AND SO.corr_id = BO.corr_id and SO.queue = ’WS_shippedorders_topic’;
/* Average waiting time in the backed order queue: */
SELECT SUM(BACK.deq_time - BACK.enq_time)/count (*) AVG_BACK_TIME
FROM WS.AQ$WS_orders_mqtab BACK
WHERE BACK.msg_state = ’PROCESSED’ AND BACK.queue = ’WS_backorders_topic’;
Supporting Oracle Real Application Clusters in JMS
Oracle Real Application Clusters can be used to improve AQ performance by
allowing different queues to be managed by different instances. You do this by
specifying different instance affinities (preferences) for the queue tables that store
the queues. This allows queue operations (enqueue/dequeue) or topic operations
(publish/subscribe) on different queues or topics to occur in parallel.
The AQ queue monitor process continuously monitors the instance affinities of the
queue tables. The queue monitor assigns ownership of a queue table to the specified
primary instance if it is available, failing which it assigns it to the specified
secondary instance.
If the owner instance of a queue table terminates, the queue monitor changes
ownership to a suitable instance such as the secondary instance.
AQ propagation is able to make use of Real Application Clusters, although it is
transparent to the user. The affinities for jobs submitted on behalf of the
propagation schedules are set to the same values as that of the affinities of the
respective queue tables. Thus, a job_queue_process associated with the owner
instance of a queue table will be handling the propagation from queues stored in
that queue table thereby minimizing pinging. Additional discussion on this topic
can be found under AQ propagation scheduling (see "Scheduling a Queue
Propagation"in Chapter 9, "Administrative Interface"and Oracle9i Real Application
Clusters Setup and Configuration.)
Creating Applications Using JMS 12-19