EMS Destination Properties |
In this Tibco EMS tutorial we will understand different EMS destination properties. |
Secure
Authenticate users before giving access to a queue or topic. Only authenticated users can send or receive message from the secured destination. Syntax: addprop [queue|topic] <<queue|topic name>> secure |
Channel
Setting this property make a topic multicast. This property can be only set to a topic by which messages send to these topics are broadcasted. Syntax: <<topic name>> channel=<<channel name>> Example: topic.foo channel=mycast |
Exclusive
[Only for queue] By default the EMS server send the messages on a queue to the consumers in a round-robin fashion. By setting this property the message on the queue are send to only one consumer (Primary) and other consumers (Secondary) on the same queue are at standby. If the primary consumer fails the standby consumer becomes primary. |
Expiration The messages are destroyed or send to the undelivered queue if the message in not consumed within the time specified. |
Flowcontrol
Server slows down the producers to the rate at which the consumer is receiving it if the specified max size used to store pending messages exceeds. |
MaxBytes and MaxMsg
Max size to store overall message in a queue or topic. Message are rejected on exceeding. MaxMsg: |
Overflow Policy
Used to change the effect of max bytes and max message on exceeding the specified limit. Properties that can be assigned: Discard Old: For queue and topic the oldest messages are discarded before they are delivered to the subscriber/consumer. Reject Incoming: For queue and topic the new messages are discarded before they are delivered to the subscriber/consumer and error message is send to the to the producer. |
Trace
Enables tracing for a destination. Syntax: addprop [queue|topic] <<queue|topic name>> trace |
Import
Allows messages published by an external system to be |
Export
Allows messages published by a client to a topic to be exported to the external systems with configured transports. |
EMS Destination Properties

Hi, from the EMS 7.0 manual regarding discardOld:
discardOld
For topics, discardOld specifies that, if any of the subscribers have an
outstanding number of undelivered messages on the server that are over the
message limit, the oldest messages are discarded before they are delivered to the
subscriber.
The discardOld setting impacts subscribers individually. For example, you might
have three subscribers to a topic, but only one subscriber exceeds the message
limit. In this case, only the oldest messages for the one subscriber are discarded,
while the other two subscribers continue to receive all of their messages.
When messages for a topic or queue exceed the maxbytes or maxmsgs value, the
oldest messages are silently discarded. No error is returned to the producer.
–> It states that ‘No error is returned to the producer’ where on your site it states that an error is sent to the producer. Quite a difference
Thanks for pointing that out. The point for discardOld mentioned referred to EMS 6.0 doc. Also, I have made the correction on my post for the same.