TIBCO EMS FAQ's (Part 2)

1. What are the messaging models does EMS support?

a. Point-to-Point (Queue)

b. Publish and Subscribe (Topic)

c. Multicast (Topic)

2. What are the messages bodies are supported by the EMS?

• Map Message

• Text Message

• Stream Message

• Bytes Message

• Object Message

3. What are the limitations of the Durable Subscriber?

• As long as the durable subscriber exists

• Expiration time of the message

• Storage limit of that Topic

4. What is the Maximum message size is supported by EMS?

EMS supports messages up to a maximum size of 512MB. However, we recommend that application programs use smaller messages, since messages approaching this maximum size will strain the performance limits of most current hardware and operating system platforms

5. What are the EMS Destination features?

• Secure Property

• Trace Property

• Store Property

• Redelivery policy

• Flow control

• Exclusive property for queues

6. What are the different types of messages that can be used in EMS

• Text

• Simple

• Bytes

• Map

• XML test

• Object

• Object ref

• Stream

7. What are the extra features are available in EMS apart from JMS?

• The JMS standard specifies two delivery modes for messages, PERSISTENT and NON_PERSISTENT. EMS also includes a RELIABLE_DELIVERY mode that eliminates some of the overhead associated with the other delivery modes.

• For consumer sessions, you can specify a NO_ACKNOWLEDGE mode so that consumers do not need to acknowledge receipt of messages, if desired. EMS also provides an EXPLICIT_CLIENT_ACKNOWLEDGE and EXPLICIT_CLIENT_DUPS_OK_ACKNOWLEDGE mode that restricts the acknowledgement to single messages

• EMS extends the MapMessage and StreamMessage body types. These extensions allow EMS to exchange messages with TIBCO Rendezvous and ActiveEnterprise formats that have certain features not available within the JMS MapMessage and StreamMessage

8. What is structure of JMS Message?

• Header(Required)

• Properties(optional)

• Body(optional)

9. Where does the undelivered messages will be stored?

• If a message expires or has exceeded the value specified by the maxRedelivery property on a queue, the server checks the message’s JMS_TIBCO_PRESERVE_UNDELIVERED property. If JMS_TIBCO_PRESERVE_UNDELIVERED is set to true, the server moves the message to the undelivered message queue, $sys.undelivered. This undelivered message queue is a system queue that is always present and cannot be deleted. If JMS_TIBCO_PRESERVE_UNDELIVERED is set to false, the message will be deleted by the server

• You can only set the undelivered property on individual messages, there is no way to set the undelivered message queue as an option at the per-topic or per-queue level

10. If a persistent message is published on to a TOPIC, Does these messages will store on disk if topic doesn’t have durable subscriber or subscriber with a fault-tolerant connection?

No. Persistent messages published to a topic are written to disk only if that topic has at least one durable subscriber or one subscriber with a fault-tolerant connection to the EMS server. In the absence of a durable subscriber or subscriber with a fault-tolerant connection, there are no subscribers that need messages resent in the event of a server failure. In this case, the server does not needlessly save persistent messages. This improves performance by eliminating the unnecessary disk I/O to persist the messages