This topic contains sections marked as revised for this release

WebSphere Message Brokers
File: ae00270_
Writer: Laura Cowen

Concept topic

This build: July 31, 2007 21:27:09

Execution groups

An execution group is a named grouping of message flows that have been assigned to a broker. The broker enforces a degree of isolation between message flows in distinct execution groups by ensuring that they execute in separate address spaces, or as unique processes.

Each execution group is started as a separate operating system process, providing an isolated runtime environment for a set of deployed message flows. Within an execution group, the assigned message flows run in different thread pools. You can specify the size of the thread pool (that is, the number of threads) that are assigned for each message flow by specifying the number of additional instances of each message flow.

A single default execution group is set up ready for use when you create a reference to a broker in the workbench. By setting up additional execution groups, you can isolate message flows that handle sensitive data such as payroll records, or security information, or unannounced product information, from other non-sensitive message flows.

If you create additional execution groups, you must give each group a name that is unique within the broker, and assign and deploy one or more message flows to each one.

You can create and deploy execution groups either in the workbench, or using commands.

An execution group process is also known as a DataFlowEngine (DFE); this term is typically used in problem determination scenarios (trace contents, diagnostic messages, and so on). A DFE is created as an operating system process, and has a one-to-one relationship with the named execution group. If more than one message flow runs within an execution group, multiple threads are created within the DFE process.

64-bit execution groups

When you create an execution group, you can specify whether you want to create a 32-bit execution group or a 64-bit execution group.

Why create 64-bit execution groups?
There are two main benefits to creating 64-bit execution groups:
  • If you are using both a 64-bit queue manager and a 64-bit execution group, you can run the broker as a WebSphere MQ trusted application, which means that the broker can handle WebSphere MQ operations faster than a normal broker. You cannot run a broker as a trusted application if you have a 64-bit broker queue manager but only a 32-bit execution group.
  • You can allocate large amounts of contiguous memory. Message flows that are deployed to a 64-bit execution group can process larger messages than message flows that are deployed to a 32-bit execution group.
Supported platforms
You can create 64-bit execution groups only on the following UNIX systems:
  • AIX
  • Solaris (SPARC platform)
  • HP-UX (PA-RISC platform)
  • HP-UX (Integrity platform)

When you deploy the first message flow to a new 64-bit execution group, the broker determines whether a 64-bit execution group is supported on that broker; if not, the deployment fails with error message BIP2825.

See Enabling connections to the databases to check whether you need to define 32-bit data source names (DSNs), 64-bit DSNs, or both when you are using a 64-bit execution group or when you configure global coordination of message flows that are deployed to a 64-bit execution group.

Considerations when using 64-bit execution groups
The following list describes the main differences between using 32-bit and 64-bit execution groups:
Execution group
You must create a new execution group and specify, at creation time, that it will be a 64-bit execution group. You cannot change an existing 32-bit execution group into a 64-bit execution group.
Broker queue manager
The broker's queue manager must be 64-bit.
Databases
If you use a DB2 database, it must reside in a 64-bit DB2 instance. With Oracle, Sybase, Informix, and SQLServer, you can use 32-bit or 64-bit databases depending on how you connect the broker system to the database server.
User-defined nodes
You must recompile as 64-bit applications any 32-bit user-defined nodes. For more information, see Installing a user-defined extension to current and past versions of the broker.
Message flows
When you deploy a message flow to an execution group, the message flow runs as either a 32-bit application or a 64-bit application depending on whether the execution group is 32-bit or 64-bit. You do not need to change existing message flows to run in a 64-bit execution group unless the message flow includes a user-defined node that is compiled for a 32-bit application.
Flow debugger
The flow debugger is not supported for use with message flows that are deployed to 64-bit execution groups.
Related concepts
Brokers
Message flows overview
Deployment overview
Related tasks
Adding an execution group to a broker
Using WebSphere MQ trusted applications
Related reference
Supported databases
Notices | Trademarks | Downloads | Library | Support | Feedback

Copyright IBM Corporation 1999, 2007Copyright IBM Corporation 1999, 2007. All Rights Reserved.
This build: July 31, 2007 21:27:09

ae00270_ This topic's URL is: