Advanced Queuing - Oracle

Support for Statistics Views
Structured Payloads
Basic statistics about queues are available using the GV$AQ view.
General Features of Advanced Queuing
You can use object types to structure and manage message payloads. RDBMSs in
general have a richer typing system than messaging systems. Since Oracle is an
object-relational DBMS, it supports both traditional relational types as well as
user-defined types. Many powerful features are enabled as a result of having
strongly typed content, such as content whose format is defined by an external type
system. These include:
Content-based routing: Advanced Queuing can examine the content and
automatically route the message to another queue based on the content.
Content-based subscription: a publish and subscribe system is built on top of a
messaging system so that you can create subscriptions based on content.
Querying: the ability to execute queries on the content of the message enables
message warehousing.
To see this feature applied in the context of the BooksOnLine scenario, refer to
"Structured Payloads" on page 8-11.
Retention and Message History
The systems administrator specifies the retention duration to retain messages after
consumption. Advanced Queuing stores information about the history of each
message, preserving the queue and message properties of delay, expiration, and
retention for messages destined for local or remote receivers. The information
contains the enqueue and dequeue times and the identification of the transaction
that executed each request. This allows users to keep a history of relevant messages.
The history can be used for tracking, data warehouse, and data mining operations,
as well as specific auditing functions.
To see this feature applied in the context of the BooksOnLine scenario, refer to
Retention and Message History on page 8-27.
Tracking and Event Journals
If messages are retained, they can be related to each other. For example, if a message
m2 is produced as a result of the consumption of message m1, m1 is related to m2.
This allows users to track sequences of related messages. These sequences represent
Introduction to Oracle Advanced Queuing 1-9