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C. Scott Andreas updated CASSANDRA-13491: ----------------------------------------- Component/s: Metrics > Emit metrics for JVM safepoint pause > ------------------------------------ > > Key: CASSANDRA-13491 > URL: https://issues.apache.org/jira/browse/CASSANDRA-13491 > Project: Cassandra > Issue Type: New Feature > Components: Metrics > Reporter: Simon Zhou > Priority: Major > > GC pause is not the only source of latency from JVM. In one of our recent > production issues, the metrics for GC looks good (some >200ms and longest > 500ms) but GC logs show periodic pauses like this: > {code} > 2017-04-26T01:51:29.420+0000: 352535.998: Total time for which application > threads were stopped: 19.8835870 seconds, Stopping threads took: 19.7842073 > seconds > {code} > This huge delay should be JVM malfunction but it caused some requests > timeout. So I'm suggesting to add support for safepoint pause for better > observability. Two problems though: > 1. This depends on JVM. Some JVMs may not expose these internal MBeans. This > is actually the same case for existing GCInspector. > 2. For Hotspot, it has HotspotRuntime as an internal MBean so that we can get > safepoint pause. However, there is no notification support for that. I got > error "MBean sun.management:type=HotspotRuntime does not implement > javax.management.NotificationBroadcaster" when trying to register a listener. > This means we will need to pull the safepoint pauses from HotspotRuntime > periodically. > Reference: > http://blog.ragozin.info/2012/10/safepoints-in-hotspot-jvm.html > Anyone think we should support this? -- This message was sent by Atlassian JIRA (v7.6.3#76005) --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@cassandra.apache.org For additional commands, e-mail: commits-h...@cassandra.apache.org