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ProcessServiceQueue fail to find instance from queue



A JMS MDB service is configured to consume incoming messages asynchronously though a service request processor rule. It is configured to use the out of the box SYSTEM-QUEUE-EXECUTIONREQUEST-SERVICE-DEFAULT and ProcessServiceQueue agent.

Messages remains stuck in the SYSTEM-QUEUE-EXECUTIONREQUEST-SERVICE-DEFAULT queue with 0 attempts from the agent and a InstanceNotFound exception is logged by the agent.

This behaviour is erratic: some incoming messages are processed immediately and correctly by the agent.

Error Messages

[11/24/15 10:13:38:446 CET] 0000009e SystemOut O 2015-11-24 10:13:38,445 [PRPCWorkManager : 16] [ STANDARD] [ ] [ YourApp:01.01] ( async.agent.QueueProcessor) WARN YourOperator - Failed to dequeue item: SYSTEM-QUEUE-EXECUTIONREQUEST-SERVICE-DEFAULT 14483564182870007D70E35D0D4FB96B3EF4610212F35644 for processing InstanceNotFound Queue SYSTEM-QUEUE-EXECUTIONREQUEST-SERVICE-DEFAULT SYSTEM-QUEUE-EXECUTIONREQUEST-SERVICE-DEFAULT 14483564182870007D70E35D0D4FB96B3EF4610212F35644
at com.pega.pegarules.session.internal.async.agent.QueueManagerImpl.dequeue(
at com.pega.pegarules.session.internal.async.agent.QueueManagerImpl.dequeue(
at com.pega.pegarules.session.internal.async.agent.QueueProcessor.execute(
at com.pega.pegarules.session.internal.PRSessionProviderImpl.performTargetActionWithLock(
at com.pega.pegarules.session.internal.PRSessionProviderImpl.doWithRequestorLocked(
at com.pega.pegarules.session.internal.PRSessionProviderImpl.doWithRequestorLocked(
at com.pega.pegarules.session.internal.async.Agent.runBatchTask(
at com.pega.pegarules.session.internal.engineinterface.etier.impl.AsyncServant.processAsyncTask(
at com.pega.pegarules.session.internal.engineinterface.etier.impl.AsyncServant.invoke(
at com.pega.pegarules.session.internal.engineinterface.etier.impl.EngineImpl._invokeEngine_privact(
at com.pega.pegarules.session.internal.engineinterface.etier.impl.EngineImpl.invokeEngine(
at com.pega.pegarules.session.internal.engineinterface.etier.ejb.EngineBean.invokeEngine(
at sun.reflect.GeneratedMethodAccessor71.invoke(Unknown Source)

Steps to Reproduce

1. Configure a JMS MDB service to process messages asynchronously using a request processor rule from the default SYSTEM-QUEUE-EXECUTIONREQUEST-SERVICE-DEFAULT queue;
2. Put a message on the JMS queue and wait it is consumed by the Pega listener;
3. Open the SMA and display the SYSTEM-QUEUE-EXECUTIONREQUEST-SERVICE-DEFAULT queue: some messages remains stuck in the queue with 0 attempts.

Root Cause

A defect in Pegasystems’ code or rules. the the processing mode for JMS Service is set as Asynchronous. this can leave queue items with status as "Immediate".
these queue items should be processed separately. refer
HFix-7360 which describes the additional steps required.


Perform the following local-change:

1. Create an custom Agent in your application ruleset, similar to “ProcessServiceQueue” in “Pega-IntSvcs” ruleset

2. Use “ProcessImmediateQueueItems” Activity instead of “ProcessQueue”.

Suggest Edit

Published January 31, 2016 - Updated December 2, 2021

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