EMS Queues and Topics – In depth

Queue uses point to point messaging pattern. Point-to-point messaging has one producer and one consumer per message. Message producer/sender sends a message to the EMS queue and the message consumer retrieves messages from the queue and sends acknowledgement that the message was received.

Delivery Mode:(Persistent, Non–Persistent and EMS Reliable Delivery)
Persistent: Message are stored on the disk. In case the EMS server or queue is restored at later point the messages are not deleted.
Storage type: file based, Database and Mstore.

Persistent Queue Properties:-
Non-Fail Safe: Writes messages received using asynchronous mode means messages which are received at a given time are stored in the buffer and then written to the disk. In case of any failure in EMS server messages in buffer can be lost.
Fail Safe: Writes messages received using synchronous mode means all messages which are received, are directly written to the disk and no buffer is maintained. In case of EMS server failure no message is lost.

Tibco EMS Reliable Delivery: No acknowledgement is send back from the queue to the message provider on receiving of the message.

Non-Persistent: Messages are stored in memory. In case of server or queue crash messages cannot be restored when server is up.

Topic uses publisher and subscriber based model in which 1 sender sends the message to multiple receivers. For each subscriber listening to a topic a copy of the message is created (EX: if there are 10 subscriber are on a topic; 10 copy of a message is created each for a subscriber).

Durables Subscriber: Messages are stored on the disk, thus messages can be received at later point of time when the durable subscriber is available.

Non-Durables: If the subscriber is not listening to the topic the message is deleted.

Creating Queue or Topic
Syntax: create queue <<queue/topic name>>
Queue Example: create queue testqueue
Topic Example: create topic testtopic

Show list of Queues or Topics
Queue Example: create queues
Topic Example: create topics

Show a Queue or Topic
Syntax: show queue|topic <<queue/topic name>>
Queue Example: show queue testqueue
Topic Example: show topic testtopic

Purge Queues or Topics
Syntax: purge queue|topic <<queue/topic name>>
Queue Example: purge queue testqueue
Topic Example: purge topic testtopic

Delete Queues or Topics
Syntax: delete queue|topic <<queue/topic name>>
Queue Example: delete queue testqueue
Topic Example: delete topic testtopic