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ERROR - Trying to use a recycled thread



StaleThreadError occurs multiple times a day on the Production server. However, this does not impact the application.

Error Messages
[egaRULES UsageDaemon] [STANDARD] [ ] [ ] (mgmt.base.ThreadData) ERROR   - Trying to use a recycled thread; Thread has been recycled;    
at com.pega.pegarules.session.internal.mgmt.base.ThreadData.validateUse( ~[prprivate.jar:?];    
at com.pega.pegarules.session.internal.mgmt.PRThreadImpl.validateUse( ~[prprivate.jar:?];    
at com.pega.pegarules.session.internal.mgmt.PRThreadImpl.getStreamChangeTrackerMap( ~[prprivate.jar:?];    
at com.pega.pegarules.session.internal.mgmt.autostreams.StreamChangeTracker.trackChangeForAjaxDrift( ~[prprivate.jar:?];    
at com.pega.pegarules.session.internal.PRSessionProviderImpl.trackChangeForAjaxDrift( ~[prprivate.jar:?];    
at ~[prprivate.jar:?];    
at ~[prprivate.jar:?];    
at ~[prprivate.jar:?];

Steps to Reproduce

Not Applicable

Root Cause

In the logs, the pushmemoryusage activity was traced each time the Stale Thread exception occurred.
    com.pega.pegarules.session.internal.engineinterface.etier.impl.EngineImpl.invokeEngine( ~[prprivate.jar:?]     at com.pega.pegarules.session.internal.engineinterface.etier.impl.EngineImpl.invokeEngine( ~[prprivate.jar:?]
    at ~[prprivate.jar:?]
    at ~[prprivate.jar:?]
    at sun.reflect.GeneratedMethodAccessor271.invoke(Unknown Source) ~[?:?]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke( ~[?:1.8.0_131]
    at java.lang.reflect.Method.invoke( ~[?:1.8.0_131]
    at sun.reflect.misc.Trampoline.invoke( ~[?:1.8.0_131]
    at sun.reflect.GeneratedMethodAccessor57.invoke(Unknown Source) ~[?:?]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke( ~[?:1.8.0_131]
    at java.lang.reflect.Method.invoke( ~[?:1.8.0_131]
    at sun.reflect.misc.MethodUtil.invoke( ~[?:1.8.0_131]
    at$ ~[?:1.8.0_131]
    at Method) ~[?:1.8.0_131]
    at$JavaSecurityAccessImpl.doIntersectionPrivilege( ~[?:1.8.0_131]
    at ~[?:1.8.0_131]
    at ~[?:1.8.0_131]
    at ~[prpublic.jar:?]
    at ~[prpublic.jar:?]
    at ~[prpublic.jar:?]    at com.pegarules.generated.activity.ra_action_pushmemoryusage_22fb89b93a5e9a5a51f36a4a16dd9ef8.step4_circum0( ~[?:?]
    at com.pegarules.generated.activity.ra_action_pushmemoryusage_22fb89b93a5e9a5a51f36a4a16dd9ef8.perform( ~[?:?]


Here’s the explanation for the reported behavior:

PushMemoryUsage is an Autonomic Event Services (AES) agent that provides Pega Predictive Diagnostic Cloud (PDC) with the overall health of all the nodes in a cluster. This is then displayed in the PDC landing page.


Published December 12, 2018 - Updated October 8, 2020

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