Advanced Queuing - Oracle

Basic Queuing
Basic Queuing Illustrated
Modeling Queue Entities
Basic Queuing — One Producer, One Consumer
At its most basic, one producer may enqueue different messages into one queue.
Each message will be dequeued and processed once by one of the consumers. A
message will stay in the queue until a consumer dequeues it or the message expires.
A producer may stipulate a delay before the message is available to be consumed,
and a time after which the message expires. Likewise, a consumer may wait when
trying to dequeue a message if no message is available. Note that an agent program,
or application, can act as both a producer and a consumer.
Basic Queuing — Many Producers, One Consumer
At a slightly higher level of complexity, many producers may enqueue messages
into a queue, all of which are processed by one consumer.
Basic Queuing — Many Producers, Many Consumers of Discrete Messages
In this next stage, many producers may enqueue messages, each message being
processed by a different consumer depending on type and correlation identifier. See
Figure 7–2.
Figure 7–2 portrays a queue table that contains one queue into which messages are
being enqueued and from which messages are being dequeued.
Modeling and Design 7-3