Getting "Unexpected metric query error" in MOM log after upgrading to 10.5.1

Products

• CA Application Performance Management Agent (APM / Wily / Introscope)
• INTROSCOPE

Issue/Introduction

Observed the following error in the MOM's IntroscopeEnterpriseManager.log since upgraded to 10.5.1:

[ERROR] [PO:client_main Mailman 1] [Manager.MetricCalculatorBean] Unexpected metric query error
com.wily.introscope.spec.server.beans.metricdata.MetricQueryException: com.wily.introscope.spec.metric.AgentNotFoundException: Unknown Error
    at com.wily.introscope.server.beans.metricdata.persisted.HistoricalDataFetcherFromCache.getValues
       (HistoricalDataFetcherFromCache.java:64)
    at com.wily.introscope.server.beans.metricdata.persisted.PersistedQueryHelper.executeQueryBlob
       (PersistedQueryHelper.java:541)
    at com.wily.introscope.server.beans.metricdata.live.LiveMetricSubscriptionManager.registerLiveDataQuery
       (LiveMetricSubscriptionManager.java:167)
    at com.wily.introscope.server.beans.metricdata.MetricDataManager$ExecuteAsyncCommand.run
       (MetricDataManager.java:933)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)
Caused by: com.wily.introscope.spec.metric.AgentNotFoundException: Unknown Error
    at com.wily.introscope.server.enterprise.entity.agent.AgentEntity.getWatchedAgent(AgentEntity.java:2457)
    at com.wily.introscope.server.enterprise.entity.agent.AgentEntity.getRecentHistory(AgentEntity.java:3484)
    at com.wily.introscope.server.enterprise.entity.agent.AgentEntity.getRecentHistory(AgentEntity.java:1)
    at com.wily.introscope.server.beans.metricdata.persisted.HistoricalDataFetcherFromCache.getValues
       (HistoricalDataFetcherFromCache.java:41)
    at com.wily.introscope.server.beans.metricdata.persisted.HistoricalDataFetcherFromCache.getValues
       (HistoricalDataFetcherFromCache.java:62)
    ... 6 more

Environment

Application Performance Management 10.5.1

Cause

According to the code, the exception occurs when EM is trying get values for all the metrics in a query and it could not get the value of a particular metric as that metric does not exist. The consequence of this ERROR is that live query could return an empty graph initially and a live search returns error with no result.

Resolution

The issue has been fixed with a code change in 10.5.2, 10.6 and onward.