[IBM i][AIX Solaris HP-UX Linux Windows]

Thread pool settings

Use this page to enable components of the server to reuse threads and continue processing without having to create new threads at run time. Creating new threads expends time and resources.

[z/OS]This page is not available for the z/OS® platform because thread pools are not used in a z/OS environment.

You use the administrative console to configure thread pools. Two navigation paths are available to configuring thread pools:
  • General thread pools
  • Orb Service thread pool

General thread pools

There are a variety of thread pools to configure. You use the administrative console to navigate to the page where you can configure threadpools.

To view this administrative console page, click Servers > Server Types > WebSphere application servers > server_name > Thread pools (Under Additional Properties), and select the thread pool that you need to configure. You can then observe the Name, Description, Minimum size, Maximum size, Thread inactivity timeout, and an option box to allow or not allow thread allocation beyond maximum thread size.

Support configurations: Because these administrative console panels display information dynamically, you might not see all of the fields listed on any particular panel.
The various thread pools you may see are:
  • Default ThreadPool
  • ORB.thread.pool
  • SIBFAPInboundThreadPool
  • SIBFAPThreadPool
  • SIBMSRAThreadPool
  • TCPChannel.DCS
  • WMQJCAResourceAdapter
  • WebContainer
  • server.startup

ORB Service thread pool

You use the administrative console to navigate to the appropriate page where you can configure the ORB Service thread pool.

ORB Service thread pools - To view this administrative console page, click Servers > Server Types > Application servers > server_name > Container services > ORB Service

After the Pass by reference check box, you can click Thread Pool Settings to make any thread pool adjustments for ORB service. Only the Minimum, Maximum, and Thread inactivity timeout are displayed.

Name

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

This field is not displayed for the ORB service thread pool, when you clicked thread pool settings.

Information Value
Data type String

Description

A text description of the thread pool.

This field is not displayed for the ORB service thread pool, when you clicked thread pool settings.

Information Value
Data type String

Minimum size

Specifies the minimum number of threads to allow in the thread pool. When an application server starts, no threads are initially assigned to the thread pool. Based on the workload, the application server adds threads to the thread pool until the number of threads in the pool equals the number that is specified in the Minimum size field. As the workload changes, threads are either added or removed. However, the number of threads in the thread pool is always greater than the number that is specified in the Minimum size field, even if some of the threads are idle.

Information Value
Data type Integer

Maximum size

Specifies the 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.

Information Value
Data type Integer

Thread inactivity timeout

Specifies the number of milliseconds of inactivity that needs to 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.

Supported configurations: You cannot set the inactivity timeout to a negative number by using the administrative console. Modify the value directly in the server.xml file to set a negative number.
Information Value
Data type Integer
Units Milliseconds
Default values for thread inactivity timeout corresponding to these thread pools follow:
  • Default ThreadPool - 5000
  • ORB.thread.pool - 3500
  • SIBFAPInboundThreadPool - 5000
  • SIBFAPThreadPool - 5000
  • SIBMSRAThreadPool - 5000
  • TCPChannel.DCS - 5000
  • WMQJCAResourceAdapter - 5000
  • WebContainer - 60000
  • server.startup - 30000
  • ORB Service Thread Pool - 3500

Allow thread allocation beyond maximum thread size

Specifies whether the number of threads can increase beyond the maximum size that is 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 required work items are completed. If set to true, the number of threads can increase beyond the maximum size configured for the thread pool.

Information Value
Data type Boolean
Default false