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EJB Timer Service settings

 

Use this page to configure and manage the EJB Timer Service for a specific EJB container.

To view this console page, click Servers >Application Servers > servername > EJB Container Settings > EJB Timer Service Settings.

The two radio buttons that appear on this page offer you choices that are mutually exclusive.


 

Related tasks


Configure a Timer Service for network deployment
Configure a Timer Service

 

Related Reference


Example: Using the Timer Service
Timer service commands

 

Scheduler Type

 

Use Internal EJB Timer Service Scheduler Instance

WAS provides an internal scheduler instance for use by the EJB Timer Service. The internal scheduler instance is pre-configured for basic EJB Timer functionality, and provides limited configuration settings for an EJB Timer Service. Clicking this button specifies to use the internal scheduler instance to manage your tasks. They are persisted to a Cloudscape database associated with the server process. Selecting this choice locks out the Use Custom Scheduler Instance option.

This is the default choice.

 

Use Custom Scheduler Instance

You can perform a more advanced configuration for the EJB Timer Service by defining a custom scheduler instance. Scheduler configuration provides more configuration options than the internal EJB Timer Service pre-configured scheduler instance. You might want to define a custom scheduler instance when running in a clustered environment, allowing all cluster members to run with a single scheduler instance. This enables EJB Timers created on one cluster member to execute on other cluster members. Providing a custom scheduler instance also enables EJB Timers to be maintained in the same database as other scheduled tasks. Selecting this choice locks out the Use Internal EJB Timer Service Scheduler Instance option

 

Data source JNDI Name

Specifies the Java Naming and Directory Interface (JNDI) name of the data source where persistent EJB Timers are stored for this EJB container. Any data source available in the name space can be used for EJB Timers. Multiple EJB containers can share a single data source while using different tables by specifying a table prefix.

Data type String
Default jdbc/DefaultEJBTimerDataSource

 

Data source alias

Authentication alias to a user name and password used to access the data source.

Data type String

 

Table prefix

A string prepended to the EJB Timer Service table names (TASK, TREG, LMGR and LMPR). These tables are created during server start if they do not already exist. See help on the Scheduler Service for information about manually creating these tables. Multiple independent EJB Timer Services can share the same database if each instance specifies a different prefix string.

Data type String
Default EJBTIMER_

 

Poll interval

The interval at which the EJB Timer Service daemon polls the database. Each poll operation can be expensive. If the interval is extremely small and there are many scheduled tasks, polling can consume a large portion of system resources. New Timers set to expire sooner than this interval might not execute until the interval ends. If this value is too large, a potentially large number of timer events might be read into memory, because all the timer events occurring in the next poll interval are read in each time.

Data type Integer
Units seconds
Default 300
Range 3 -- 1800

 

Number of timer threads

The number of threads used to execute concurrent EJB Timer tasks. Setting the number of Timer Threads to zero disables the EJB Timer Service.

Data type Integer
Default 1
Range 0 -- 500

 

Scheduler JNDI name

This field is only used when the Use Custom Scheduler Instance choice is made. It specifies the JNDI name of a custom Scheduler instance to use for managing and persisting EJB Timers. Internal EJB Timer Service Scheduler Instance configuration information is not applied to the specified Scheduler instance.

Data type String