Sun Java System Message Queue 3 2005Q1 Administration Guide |
Chapter 15
Physical Destination Property ReferenceThis chapter describes the properties you can set for each type of physical destination. You can set the property values when you create or update a physical destination.
For auto-created destinations, you set default values in the broker’s instance configuration file (see Table 14-4).
Table 15-1 Physical Destination Properties
Property
Destination
TypeDefault Value
Description
maxNumMsgs1
Queue Topic
-1
(unlimited)The maximum number of unconsumed messages allowed in the destination.
For the dead message queue, the default value is 1000.
maxTotalMsgBytes1
Queue
Topic
-1
(unlimited)The maximum total amount of memory, in bytes, allowed for unconsumed messages in the destination.
The default value for the dead message queue is 10 Mbytes.
limitBehavior
Queue
Topic
REJECT_
NEWESTA string specifying how the broker responds when a memory-limit threshold is reached. Values are:
FLOW_CONTROL — Slows down producers.
REMOVE_OLDEST — Throws out the oldest messages.
REMOVE_LOW_PRIORITY — Throws out the lowest priority messages according to age of the messages (producing client receives no notification of message deletion).
REJECT_NEWEST — Rejects the newest messages. The producing client gets an exception for rejection of persistent messages only. To use this limit behavior with non-persistent messages, set the imqAckOnProduce connection factory attribute.
If you set this property to REMOVE_OLDEST or REMOVE_LOW_PRIORITY and set the destination property useDMQ to true, the broker moves excess messages to the dead message queue.
The dead message queue itself, unlike other destinations, has the default limit behavior REMOVE_OLDEST and cannot be set to FLOW_CONTROL behavior.
maxBytesPerMsg
Queue
Topic
-1
(unlimited)The maximum size, in bytes, of any single message allowed in the destination. The producing client gets an exception for rejection of persistent messages, but no notification for rejection of non-persistent messages, unless the ackOnProduce property is set.
maxNumProducers
Queue
Topic
-1
(unlimited)The maximum number of producers allowed for the destination. When this limit is reached, no new producers can be created.
You cannot set this property for the dead message queue.
maxNumActiveConsumers
Queue only
1
The maximum number of consumers that can be active in load-balanced delivery from a queue destination. A value of -1 means an unlimited number.
Platform Edition limits this value to 2.
maxNumBackupConsumers
Queue only
0
The maximum number of backup consumers that can take the place of active consumers, if any fail during load-balanced delivery from a queue destination. A value of -1 means an unlimited number.
Platform Edition limits this value to 1 (one).
consumerFlowLimit
Queue
Topic
Topics: 1000
Queues: 1000
The maximum number of messages that will be delivered to a consumer in a single batch. In load-balanced queue delivery, this is the initial number of queued messages routed to active consumers before load-balancing commences.
A destination consumer can override this limit by specifying a lower value on a connection. A value of -1 means an unlimited number.
localDeliveryPreferred
Queue only
false
For load-balanced queue delivery in broker clusters, a boolean value specifying whether messages should be delivered to remote consumers only if there are no consumers on the local broker. Requires that the destination not be restricted to local-only delivery (isLocalOnly = false).
This property does not apply to the dead message queue.
isLocalOnly
Queue
Topic
false
For destinations in broker clusters, a boolean value specifying whether the destination is restricted to local-only delivery. If true, the destination is not replicated on other brokers, and is limited to delivering messages only to local consumers (those connected to the broker on which the destination is created). This property cannot be changed once the destination has been created.
This property does not apply to the dead message queue.
useDMQ
Queue
Topic
true
A boolean value specifying whether dead messages should be sent to the dead message queue, rather than discarded.
This property does not apply to the dead message queue.
1 In a cluster environment, this property applies to each instance of the destination in the cluster, rather than collectively to all instances in the cluster.