||Oracle Tips by Burleson
Chapter 1 -
What is Streams?
Where to use Streams
RAC, Data Guard and Streams offer different
solutions. Each methodology has its strengths, but the Streams
methodology has cleverly incorporated some of the strengths of RAC
and Data Guard.
By using the Streams based Advanced Queuing
(AQ), user applications can enqueue messages into queues, then
propagate them to the subscribing queues. The AQ process sends
notifications when messages arrive into queues, allowing the
specified action routine to execute. Usually, the action routine
involves processing the messages by de-queuing them at the
Oracle AQ has all the standard features of the
message queuing systems. It allows the establishment of
multi-consumer queues, publish and subscribe methodology, content
based routing, transformations, and gateways to other messaging
subsystems. Oracle Streams based AQ is fully integrated into the
database systems. As a result, the maintenance of persistent queues
becomes really robust. AQ stores the messages in the database
objects in a transactional order. The messages are available later,
even after they are de-queued, for secondary uses like auditing and
tracking. This is one of the main reasons for the popularity of AQ.
Event Messaging and Notification
Business organizations need to propagate a
variety of messages between different applications running on
different systems and supporting a variety of business users. Events
are basic units of business communications that convey a certain
message, situation, or status, which in turn could trigger a
specified action. The alert mechanism or notification mechanism is
built upon the simple premise of a cause and effect paradigm.
The above text is
an excerpt from:
High Speed Replication and Data
by Madhu Tumma
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