CODEWITHSUNDEEP
webspherewebsphere-8was
Sanny Pathak
Sanny Pathak

Reputation: 45

Issues in custom scheduler instance for EJB timer service in clustered environment

We have our application deployed on Websphere application server. The application is running on clustered environment with 6 Nodes. EJB timer service is configured using custom scheduler with datasource pointing to Oracle database.So when the application is deployed on cluster it triggers the Ejb timer service on Node1 which is given in the Oracle database.

Some times the value in oracle database changes automatically to some other nodes like node2 or node3 because of which EJB timer is getting stopped.Any Suggestions or advice on why it gets changed automatically.

EJB timer configuration

Server(0).components.ApplicationServer(1).components.EJBContainer(1).timerSettings.EJBTimer(0).datasourceJNDIName = jdbc/cdb_db

Server(0).components.ApplicationServer(1).components.EJBContainer(1).timerSettings.EJBTimer(0).nonPersistentTimerRetryCount = -1 Server(0).components.ApplicationServer(1).components.EJBContainer(1).timerSettings.EJBTimer(0).nonPersistentTimerRetryInterval = 300 Server(0).components.ApplicationServer(1).components.EJBContainer(1).timerSettings.EJBTimer(0).numAlarmThreads = 1 Server(0).components.ApplicationServer(1).components.EJBContainer(1).timerSettings.EJBTimer(0).numNPTimerThreads = 1 Server(0).components.ApplicationServer(1).components.EJBContainer(1).timerSettings.EJBTimer(0).pollInterval = 300 Server(0).components.ApplicationServer(1).components.EJBContainer(1).timerSettings.EJBTimer(0).tablePrefix = EJBTIMER_ Server(0).components.ApplicationServer(1).components.EJBContainer(1).timerSettings.EJBTimer(0).uniqueTimerManagerForNP = false

Upvotes: 0

Views: 231

Answers (1)

njr
njr

Reputation: 3484

As the first comment added to this question points out, it is the designed behavior of EJB Persistent Timers/Scheduler to have any one member run all of the tasks until that member isn't available or cannot respond quickly enough, in which case another member takes over.

If you don't like this behavior and want to change it so that your timer tasks can only run on a single member, you can accomplish that by stopping the scheduler poll daemon on all members except for the one that you want to run the tasks. Here is a knowledge center document which describes how to do that: https://www.ibm.com/support/knowledgecenter/en/SSAW57_8.5.5/com.ibm.websphere.nd.multiplatform.doc/scheduler/xmp/xsch_stopstart.html

Just be aware that if you do this, you will be losing out on the ability for the scheduler to automatically start running tasks on a different member should the member that you have designated to run them go down. In this case, tasks will not run at all until either of 1) the member that is allowed to run them comes back up, or 2) you manually use the aforementioned WASScheduler MBean to start the scheduler poll daemon on a different member, thus allowing tasks to run there

Upvotes: 1

Related Questions