[
https://issues.apache.org/jira/browse/HADOOP-9618?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13677214#comment-13677214
]
Todd Lipcon commented on HADOOP-9618:
-------------------------------------
Hey Hitesh. We already have the "EventCounter" log4j appender. Rather than
making one-off metrics for this, I think we should just extend the EventCounter
to take a list of regular expressions to map to metrics in the logs - eg you
could say something the following in the log4j configuration:
{code}
log4j.appender.EventCounter.WARN.gc-pauses=Detected pause in JVM
{code}
Does that seem like a more general way of achieving the above?
bq. FWIW, -XX:UseGCLogFileRotation is available in JDK 6u34 and 7u2+.
Thanks, I forgot about that new feature. Still it's nicer to have this info
exposed via log4j, and with a consistent format (the Java GC logs keep changing
format and also look different depending on which collector you're using, if I
recall correctly)
> Add thread which detects JVM pauses
> -----------------------------------
>
> Key: HADOOP-9618
> URL: https://issues.apache.org/jira/browse/HADOOP-9618
> Project: Hadoop Common
> Issue Type: New Feature
> Components: util
> Affects Versions: 3.0.0
> Reporter: Todd Lipcon
> Assignee: Todd Lipcon
> Attachments: hadoop-9618.txt
>
>
> Often times users struggle to understand what happened when a long JVM pause
> (GC or otherwise) causes things to malfunction inside a Hadoop daemon. For
> example, a long GC pause while logging an edit to the QJM may cause the edit
> to timeout, or a long GC pause may make other IPCs to the NameNode timeout.
> We should add a simple thread which loops on 1-second sleeps, and if the
> sleep ever takes significantly longer than 1 second, log a WARN. This will
> make GC pauses obvious in logs.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira
