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Yu Li commented on HBASE-14891: ------------------------------- Thanks for the note [~chenheng], it's by purpose to show the change more clearly. Let me upload another one following code format. :-) > Add log for uncaught exception in RegionServerMetricsWrapperRunnable > -------------------------------------------------------------------- > > Key: HBASE-14891 > URL: https://issues.apache.org/jira/browse/HBASE-14891 > Project: HBase > Issue Type: Improvement > Components: metrics > Reporter: Yu Li > Assignee: Yu Li > Priority: Minor > Attachments: HBASE-14891.patch > > > We are using ScheduledExecutorService#scheduleWithFixedDelay to periodically > reporting metrics. From javadoc of this method > {quote} > If any execution of the task encounters an exception, subsequent executions > are suppressed. > {quote} > We could see if any uncaught exception like NPE thrown in the task thread, > there won't be any error thrown but the task would be silently terminated. > In our real case we were making some modification to the metrics and causing > NPE carelessly, then we found metrics disappeared but cannot get a clue from > RS log. > Suggest to catch Throwable in > MetricsRegionServerWrapperImpl$RegionServerMetricsWrapperRunnable, add some > log there and suppress the exception to give it another try at next scheduled > run. -- This message was sent by Atlassian JIRA (v6.3.4#6332)