Effects of Setting the Configuration Fields

The Max Jobs and Use Activation Limit options work together to provide different concurrency limits. The Flow Limit field also affects the concurrency limit. The next table describes the effects of various combinations of these options.

Effects of various configuration settings

Max Jobs

Use Activation Limit

Flow Limit

Description

0

Cleared or selected

0

An unlimited number of process instances can be created and concurrently loaded into memory.

Use Activation Limit is ignored when Max Jobs is set to 0.

0

Cleared or selected

N

No paging of process instances. Allows up to N process instances before placing process starter in flow controlled stated.

Use Activation Limit is ignored when Max Jobs is set to 0.

1

Selected

N

One process instance is loaded into memory at a time and kept there until it completes its execution. This guarantees incoming events are processed in the order in which they occur. Up to N process instances are paged to disk, and then the process starter is placed into flow controlled state.

Note: If your goal is to sequentially process incoming events, use the Sequencing Key field on the Misc tab of the process starter. Using Max Jobs and Use Activation Limit incurs overhead as process instances are paged to disk and retrieved from disk.

1

Selected

0

Once process instance is loaded into memory at a time and kept there until it completes its execution. This guarantees incoming events are processed in the order in which they occur. There is no limit on the number of process instances that can be created and paged to disk.

Note: If your goal is to sequentially process incoming events, use the Sequencing Key field on the Misc tab of the process starter. Using Max Jobs and Use Activation Limit incurs overhead as process instances are paged to disk and retrieved from disk.

1

Cleared

N

One process instance is loaded into memory at a time, but up to N process instances are created. Incoming events can be processed in any order because process instances are not kept in memory until they complete execution.

M

Selected

0

An unlimited number of process instances can be created, but only M are loaded into memory and processed concurrently.

This setting ensures a limited amount of concurrent processing. This situation is useful if you have limited resources, such as database connections. You can set Max Jobs to a relatively small number and the Use Activation Limit option keeps each service in memory until the service completes. Each loaded process uses a machine resource until the service completes. Once a service releases the resource, a new process can be loaded into memory and the corresponding service can use the resource.

N

Same as above, except only N process instances are created before the process engine is placed in the flow controlled state.

M

Cleared

0

An unlimited number of process instances can be created, but only M are loaded into memory and processed concurrently. After M process instances are created, new process instances are paged to disk. There is no guarantee of the order in which process instances are executed.

N

Same as above, except only N process instances are created before the process engine is placed in the flow controlled state.