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https://issues.apache.org/jira/browse/YARN-2901?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14387203#comment-14387203
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Wangda Tan commented on YARN-2901:
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Hi Varun,
Thanks for updating patch, I took a look again, it's much efficient now, few
comments for Log4jWarningErrorAppeneder:
- It's better to use ReentrantReadWriteLock instead of synchronize lock, since
the class will be more concurrently/frequently read comparing to write.
- {{getElementsAndCounts}}, when it trying to get number of count for each
message, it loops elements in qualifyingTimes. So in extreme case, for
message="x", there's one message in every second, it will loops all 24 * 60 *
60 * 2 = 172800 items. Solution of this could be complex, either we don't have
to remember every second count for some time, such as hard define we only
remember #count for single message like past 1min, past 5min, past 30min, past
1h ... to avoid this problem. Or introduce tree-like structure for example
interval tree (http://en.wikipedia.org/wiki/Interval_tree) to make query more
efficient. I think remember limited number of time ranges for each message
should be enough. There seems no need to support cases like "give me error
count of 2:30:01 am to 3:40:05 pm". If you think changes are manageable, you
can do it in the patch, or you can file a ticket to address in a separated
patch.
- When map.size() > maxUniqueMessages, cleanup will be triggered, I suggest to
make a buffer that cleanup will not run too offen, such as when map.size() >
maxUniqueMessages * 2?
And could you take a look at findbugs warning and failed tests?
Wangda
> Add errors and warning stats to RM, NM web UI
> ---------------------------------------------
>
> Key: YARN-2901
> URL: https://issues.apache.org/jira/browse/YARN-2901
> Project: Hadoop YARN
> Issue Type: New Feature
> Components: nodemanager, resourcemanager
> Reporter: Varun Vasudev
> Assignee: Varun Vasudev
> Attachments: Exception collapsed.png, Exception expanded.jpg, Screen
> Shot 2015-03-19 at 7.40.02 PM.png, apache-yarn-2901.0.patch,
> apache-yarn-2901.1.patch, apache-yarn-2901.2.patch
>
>
> It would be really useful to have statistics on the number of errors and
> warnings in the RM and NM web UI. I'm thinking about -
> 1. The number of errors and warnings in the past 5 min/1 hour/12 hours/day
> 2. The top 'n'(20?) most common exceptions in the past 5 min/1 hour/12
> hours/day
> By errors and warnings I'm referring to the log level.
> I suspect we can probably achieve this by writing a custom appender?(I'm open
> to suggestions on alternate mechanisms for implementing this).
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