Configure the timer service using scripting

Use wsadmin scripting to configure the EJB timer service.

We must have a working knowledge of Jacl or Jython and wsadmin scripting.

The behavior for EJB timers is configured using the EJBTimer configuration object in the server.xml file. If we have EJB timers, we must update the EJBTimer configuration object to obtain the optimal settings for the environment.

The EJBTimer configuration object exists at the server level. This means that each server in a multi-server environment has its own EJBTimer configuration object and must be configured individually.

Tasks

1. Launch the scripting tool using the Jython or scripting language.

2. Determine the attributes on the EJBTimer configuration object that must be updated. We can update the following attributes on the EJBTimer configuration object:
   • datasourceJNDIName
   • datasourceAlias
   • tablePrefix
   • pollInterval
   • numAlarmThreads
   • schedulerJNDIName
   • numNPTimerThreads
   • nonPersistentTimerRetryCount
   • nonPersistentTimerRetryInterval
   • uniqueTimerManagerForNP

   For a complete description of each attribute, see information about EJB timer service settings.

   Four types of EJB timers exist:

   • Persistent timers, supported by a default internal scheduler instance.
   • Persistent timers, supported by a custom scheduler instance.
   • Non-persistent timers, sharing a thread pool with persistent timers.
   • Non-persistent timers, not sharing a thread pool with persistent timers.

   The server is always configured to use one of the two types of persistent timers, and one of the two types of non-persistent timers.

   The EJBTimer configuration object contains the configuration data for all four types of EJB timers. Each of the four types of timer uses a subset of the configuration attributes on the EJBTimer configuration object. All the attributes on the EJBTimer configuration object are used to configure at least one of the timer types, and none of the attributes are used to configure all the timer types. Thus, we must understand which type of timer we are configured to use, and which configuration attributes apply to that type of timer.

   Attribute	Persistent, default scheduler	Persistent, custom scheduler	Non-persistent, shared thread pool	Non-persistent, unique thread pool
   datasourceJNDIName	Yes	No, specified on custom scheduler configuration instead	No	No
   datasourceAlias	Yes	No, specified on custom scheduler configuration instead	No	No
   tablePrefix	Yes	No, specified on custom scheduler configuration instead	No	No
   pollInterval	Yes	No, specified on custom scheduler configuration instead	No	No
   numAlarmThreads	Yes	No	Yes	No
   schedulerJNDIName	No	Yes	No	No
   numNPTimerThreads	No	No	No	Yes
   nonPersistentTimerRetryCount	No	No	Yes	Yes
   nonPersistentTimerRetryInterval	No	No	Yes	Yes
   uniqueTimerManagerForNP	No	No	Yes	Yes

   The presence of a value for the schedulerJNDIName attribute determines which type of persistent timer is used. If the schedulerJNDIName attribute has a value, then a custom scheduler instance is used. If the schedulerJNDIName does not have a value, then the default internal scheduler instance is used.

   The numAlarmThreads attribute maps to the Number of timer threads option in the Persistent EJB timer configuration section of the administrative console. The numNPTimerThreads attribute maps to the Number of timer threads option in the Non-persistent EJB timer configuration section of the administrative console.

   The uniqueTimerManagerForNP attribute maps to the Share thread pool configured for persistent timers and Create a separate thread pool for non-persistent timers options in the administrative console.

   The uniqueTimerManagerForNP attribute determines if the thread pool is shared between persistent and non-persistent timers. It also determines if the numAlarmThreads or numNPTimerThreads configuration attribute is used.

   uniqueTimerManagerForNP attribute	Persistent and non-persistent timers share a thread pool	Thread configuration attribute used	Thread configuration attribute that is ignored
   true	No	numNPTimerThreads	numAlarmThreads
   false	Yes	numAlarmThreads	numNPTimerThreads

3. Obtain a reference to the correct EJBTimer configuration object and store it in a variable.

   Use Jacl:

   set timer [$AdminConfig list EJBTimer]
   

   Use Jython:

   timer = AdminConfig.list('EJBTimer') 
   

   If we have a multi-server environment, then multiple EJBTimer configuration objects are returned. Programmatically loop over the list and select the EJBTimer configuration object that corresponds to the server we must update.

   In a multi-server environment, as an alternative to programmatically looping over the list of EJBTimer objects, we can manually select the correct EJBTimer object and copy and paste it into your variable.

   For example, if the output of our AdminConfig list command is:

   (cells/myCell01/nodes/myCellManager01/servers/dmgr|server.xml#EJBTimer_1)(cells/myCell01/nodes/myNode02/servers/server1|server.xml#EJBTimer_1246050925244)

   Copy and paste the reference for the needed EJBTimer object into your variable.

   Use Jacl:

   set timer "(cells/myCell01/nodes/myNode02/servers/server1|server.xml#EJBTimer_1246050925244)"
   

   Use Jython:

   timer = "(cells/myCell01/nodes/myNode02/servers/server1|server.xml#EJBTimer_1246050925244)"
   

4. Update attributes on the EJBTimer configuration object.

   Update attributes on the EJBTimer configuration object using the AdminConfig modify command. The first argument to the command is the EJBTimer reference that obtained in the previous step. The second argument to the command is a list of name-value pairs.

   To set a retry count of 10 attempts, and a retry interval of 15 seconds between each attempt:

   Use Jacl:

    set update "{nonPersistentTimerRetryCount 10} {nonPersistentTimerRetryInterval 15}"
    $AdminConfig modify $timer $update
   

   Use Jython:

   AdminConfig.modify(timer, '[[nonPersistentTimerRetryCount "10"] [nonPersistentTimerRetryInterval "15"]]') 
   

5. Save the configuration changes.

   Use Jython:

   AdminConfig.save()
   

   Use Jacl:

   $AdminConfig save
   

6. In a network deployment environment only, synchronize the node.

   Use Jacl:

   set sync1 [$AdminControl completeObjectName type=NodeSync,node=<the node>,*]
   $AdminControl invoke $sync1 sync
   

   Using Jython:

   sync1 = AdminControl.completeObjectName('type=NodeSync,node=<the node>,*')
   AdminControl.invoke(sync1, 'sync')
   

   The node synchronization in these examples must be executed while connected to the server.

As a result of our updates, the EJBTimer configuration object now reflects the attribute values we specified. Restart the server so that the changes are updated on the server.

Subtopics

• Configure a timer service for network deployment
  We can configure the EJB timer service for timers that can persist through application server shutdowns and restarts.
• Example: Using the Timer Service with the TimedObject interface
  This example shows the implementation of the ejbTimeout() method called when the scheduled event occurs.
• EJB timer service settings
  Configure and manage the EJB timer service for a specific EJB container.
• Configure a timer service
  We can configure and manage the EJB timer service for a specific EJB container.

Commands for the AdminConfig object