Messaging engines [Settings]
A messaging engine is a component, running inside a server, that manages messaging resources for a bus member. Applications are connected to a messaging engine when they access a service integration bus.
To view this page in the console, click the following path:
Service integration -> Buses -> bus_name -> [Topology] Messaging engines -> engine_name.
Configuration tab
The Configuration tab shows configuration properties for this object. These property values are preserved even if the runtime environment is stopped then restarted.
General Properties
Name
The name of the messaging engine.
Information Value Required No Data type String
UUID
The universal unique identifier assigned by the system to this messaging engine for administrative purposes.
Information Value Required No Data type String
Description
An optional description for the messaging engine, for administrative purposes.
Information Value Required No Data type Text area
Initial state
The initial state determines whether the messaging engine is started automatically.
If this property is selected, the messaging engine starts automatically when its associated application server is started. Until the messaging engine starts, it is unavailable.
Information Value Required No Data type drop-down list Range
- Stopped
- When the associated application server is started, the messaging engine is stopped and is not available to process messages.
- Started
- When the associated application server is started, the messaging engine is started and is available to process messages.
Message store type
The type of message store used. Either file store or data store. Once the messaging engine has been created this cannot be changed, only configured.
Information Value Required No Data type drop-down list Range
- File store
- A file store is a type of message store that directly uses files in a file system through the operating system.
- Data store
- A data store consists of the set of tables that a messaging engine uses to store persistent data in a database.
High message threshold per message point
The number of messages queued on a message point on this messaging engine, at which point new messages are not accepted on the message point. However, certain messages that are already in the bus and that are being transmitted to this messaging engine might be accepted.
When the messaging engine is created, the high message threshold of the bus is used to set the default value for this property. When a message point is created on this messaging engine, the value of this property is used to set the default high message threshold for the message point.
Information Value Required No Data type Integer Range 1 through 9223372036854775807
There are implications for the Java Virtual Machine (JVM) heap size when using a high message threshold, if large numbers of messages are held on a queue (each message consumes approximately 200 bytes of storage). Therefore if we increase the high message threshold because we are expecting large numbers of messages on your queues, we should also modify the JVM heap size of the server as appropriate.
Default blocked destination retry interval
The time delay, in milliseconds, that is introduced by the system under certain circumstances before a failed message delivery to an application will be retried. This delay can be overridden by individual Queue destination configurations.
When we configure a bus destination, we can specify an associated exception destination and a maximum number of times an individual message fails to be consumed before it is put on that exception destination. Alternatively, if we do not specify an associated exception destination, the system continues to try to deliver the message. In this situation, the system attempts to deliver the message, without applying any delay, until it reaches the maximum failed deliveries limit set for the bus destination (a queue or a topic space). After the maximum failed deliveries limit is reached, the default blocked destination retry interval is applied before the message is retried.
The Default blocked destination retry interval specifies the time interval between retry attempts, which will be used by all queue and topic destinations associated with this messaging engine. We can override this default value when we configure an individual queue or topic destination.
Information Value Required No Data type Integer (milliseconds) Default The value taken from the sib.processor.blockedRetryTimeout custom property, if set. Otherwise it is set to 5000. Range 1 through 9223372036854775807
Target groups
A list of names of target groups with which the messaging engine will register.
Custom target groups are a type of target group used by JMS connection factories. When an application creates a connection to a service integration bus, it uses connection factory properties to specify suitable messaging engines to connect to. When a target type of "Custom" is specified in the connection factory targetType property, the application is connected to one of the messaging engines in the specified custom target group. A particular messaging engine is selected from the group according to the other connection factory properties that are specified.
Information Value Required No Data type Text area
Bus name
The name of the service integration bus on which the messaging engine is configured.
Information Value Required No Data type String
Bus UUID
The universal unique identifier of the service integration bus on which the messaging engine is configured.
Information Value Required No Data type String
Message points
- Mediation points
- A mediation point is created on each messaging engine to which the mediation of a mediated destination is assigned. It is used to hold messages pending delivery to the mediation.
- Queue points
- A queue point is created on each messaging engine to which a point-to-point destination is assigned. It is used to hold messages pending delivery to receiving applications.
- Publication points
- A publication point is created on each messaging engine in the bus when a publish/subscribe destination is created. The publication point on a messaging engine is used to hold messages published by applications connected to that messaging engine until they are delivered to subscribers.
Additional Properties
- Mediation execution points
- Mediation execution points for the processing of messages from mediation message points that are on an IBM MQ server.
- Service integration bus links
- A communications link between this messaging engine and a messaging engine in a foreign service integration bus.
- Mediation thread pool
- The thread pool for allocating mediation handler threads.
- Message store
- The properties for the message store in use by this messaging engine as determined by the message store type field. The message store can be either a file store or a data store.
- IBM MQ client links
- An IBM MQ client link enables JMS client applications to connect, via this messaging engine, to the service integration bus, as though it were an IBM MQ queue manager.
- IBM MQ links
- Links between the messaging engine and IBM MQ networks. Each IBM MQ link connects the messaging engine as a queue manager to IBM MQ, providing a bridge between the bus and an IBM MQ network.
- Custom properties
- Arbitrary name-value pairs of data, where the name is a property key and the value is a string value used to set internal system configuration properties. Defining a new property enables us to configure a setting beyond that which is available in the administrative console.
- Reliable messaging state
- View and manage the WS-ReliableMessaging runtime state.
Related Items
- Bus member
- The bus member associated with this messaging engine.
Runtime tab
The Runtime tab shows runtime properties for this object. These properties directly affect the current runtime environment, but are not preserved when that environment is stopped. To preserve runtime property values, change the equivalent property values on the Configuration tab.
General Properties
Status
The current status of the messaging engine. Status settings are started or stopped.
To be able to retrieve the status of messaging engines, we must be logged into the administrative console with at least monitor authority. If we do not have this authority, the messaging engine status is displayed as "Unavailable", even if the messaging engine has started.
Information Value Required No Data type String
Message points
- Queue points
- A queue point is created on each messaging engine to which a point-to-point destination is assigned. It is used to hold messages pending delivery to receiving applications.
- Publication points
- A publication point is created on each messaging engine in the bus when a publish/subscribe destination is created. The publication point on a messaging engine is used to hold messages published by applications connected to that messaging engine until they are delivered to subscribers.
- Mediation points
- A mediation point is created on each messaging engine to which the mediation of a mediated destination is assigned. It is used to hold messages pending delivery to the mediation.
Remote message points
- Remote queue points
- The remote queue points that are producing/consuming messages to/from queue points on remote messaging engines.
- Remote mediation points
- The remote mediation points that are producing messages for mediation points on remote messaging engines.
- Remote publication points
- The remote publication points that are producing messages for publication points on remote messaging engines.