Thread pool settings

 

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A thread pool enables components of the server to reuse threads, which eliminates the need to create new threads at run time. Creating new threads expends time and resources.

To configure a thread pool that an appserver uses, click...

Servers | Application Servers | server | Thread Pool | thread pool

To configure the thread pool for the ORB Service, click...

Servers | Application Servers | server | Container Services | ORB Service | Thread Pool Settings

...and then select either...

Because these console panels display information dynamically, you might not see all of the fields listed on any particular panel.

 

Configuration tab

Name

The name of the thread pool to create. The name must be unique within the server.

This field does not appear if you click thread pool settings.

Data type String

Description

A text description of the thread pool.

This field does not appear if you click thread pool settings.

Data type String

Minimum size

Minimum number of threads to allow in the pool. When an appserver starts, no threads are initially assigned to the thread pool. Threads are added to the thread pool as the workload assigned to the appserver requires them, until the number of threads in the pool equals the number specified in the Minimum size field. After this point in time, additional threads are added and removed as the workload changes. However the number of threads in the pool never decreases below the number specified in the Minimum size field, even if some of the threads are idle.

This field does not appear if you click thread pool settings.

Data type Integer
Default 10

Maximum size

Maximum number of threads to maintain in the default thread pool.

If your Tivoli Performance Viewer shows the Percent Maxed metric to remain consistently in the double digits, consider increasing the Maximum size. The Percent Maxed metric indicates the amount of time that the configured threads are used.

Data type Integer
Default 50
Recommended 50 (25 on Linux systems)

Thread inactivity timeout

Number of milliseconds of inactivity that should elapse before a thread is reclaimed. A value of 0 indicates not to wait and a negative value (less than 0) means to wait forever.

The console does not allow you to set the inactivity timeout to a negative number. To do this modify the value directly in the server.xml file.

Data type Integer
Units Milliseconds
Default 3500

Allow thread allocation beyond maximum thread size

Specify whether the number of threads can increase beyond the maximum size configured for the thread pool.

The maximum number of threads that can be created is constrained only within the limits of the Java Virtual Machine and the operating system. When a thread pool, that is allowed to grow, expands beyond the maximum size, the additional threads are not reused and are discarded from the pool after processing of the work items for which they were created is completed. When additional threads are created, a message is logged in the system log file to let you know that you went beyond the maximum size set for the thread pool.

Data type Boolean
Default Not enabled (false)




 

Related tasks


Tuning the application serving environment

 

Related Reference


Thread pool collection

 

Related information


TCP transport channel settings