Advanced Queuing - Oracle

Installation Questions
Installation Questions
If the remote queue is in a different database, we use a sequencing algorithm to
avoid the need for a two-phase commit.
When a message needs to be sent to multiple queues in the same destination, it is
sent multiple times. If the message needs to be sent to multiple consumers in the
same queue at the destination, it is sent only once.
When is it useful to create indexes on a queue table? How do I create
them?
Creating an index on the queue table is useful in the following scenarios:
a. Dequeuing using correlation ID: To expedite dequeue, an index can be
created on the column corr_id of the underlying queue table AQ$_
.
b. Dequeue using a condition: Assume this condition to the where-clause for
the SELECT on the underlying queue table. An index on
can be created to expedite the performance this
SELECT statement.
What is the performance of Java (JMS) versus the PL/SQL API for AQ?
We do not have a specific performance evaluation of JMS versus the PL/SQL API.
In general, the PL/SQL API is slightly better than the JMS API. The performance of
the JMS and PL/SQL APIs in version 8.1.7 and higher should be comparable.
How do I set up Internet access for AQ? What components are
required?
See Chapter 17 for a full discussion. The following summarizes the steps required to
set up Internet access for AQ queues:
1. Set up the AQ Servlet: If you are using a servlet execution engine that supports
the Java Servlet 2.2 specification (such as Tomcat), you must create a servlet that
extends the oracle.AQ.xml.AQxmlServlet class. If you are using a servlet
execution engine that supports the Java Servlet 2.0 specification (like Apache
Jserv), you must create a servlet that extends the
oracle.AQ.xml.AQxmlServlet20 class. Implement the init() method in
the servlet to specify database connection parameters.
6-20 Oracle9i Application Developer’s Guide - Advanced Queuing