Advanced Queuing - Oracle

General Features of Advanced Queuing
See also: Oracle9i Real Application Clusters Setup and Configuration
Scenario
In the BooksOnLine example, operations on the new_orders_queue and
booked_order_queue at the order entry (OE) site can be made faster if the two
queues are associated with different instances. This is done by creating the queues
in different queue tables and specifying different affinities for the queue tables in
the create_queue_table() command.
In the example, the queue table OE_orders_sqtab stores queue new_orders_
queue and the primary and secondary are instances 1 and 2 respectively. Queue
table OE_orders_mqtab stores queue booked_order_queue and the primary
and secondary are instances 2 and 1 respectively. The objective is to let instances 1
and 2 manage the two queues in parallel. By default, only one instance is available,
in which case the owner instances of both queue tables will be set to instance 1.
However, if Real Application Clusters are set up correctly and both instances 1 and
2 are available, then queue table OE_orders_sqtab will be owned by instance 1
and the other queue table will be owned by instance 2. The primary and secondary
instance specification of a queue table can be changed dynamically using the
alter_queue_table() command as shown in the following example. Information
about the primary, secondary and owner instance of a queue table can be obtained
by querying the view USER_QUEUE_TABLES (see "Selecting Queue Tables in User
Schema" on page 10-21 in "Administrative Interface: Views").
Note: Queue names and queue table names are converted to
upper case. Mixed case (upper and lower case together) is not
supported for queue names and queue table names.
PL/SQL (DBMS_AQADM Package): Example Code
/* Create queue tables, queues for OE */
CONNECT OE/OE;
EXECUTE dbms_aqadm.create_queue_table( \
queue_table => ’OE_orders_sqtab’,\
comment => ’Order Entry Single-Consumer Orders queue table’,\
queue_payload_type => ’BOLADM.order_typ’,\
compatible => ’8.1’,\
primary_instance => 1,\
secondary_instance => 2);
A Sample Application Using AQ 8-31