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HBase >> mail # user >> optimizing block cache requests + eviction

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Re: optimizing block cache requests + eviction
On Mon, Jul 8, 2013 at 12:22 PM, Viral Bajaria <[EMAIL PROTECTED]>wrote:

> - I tried taking a stack trace using jstack but after the dump it crashed
> the regionserver. I also did not take the dump on the offending
> regionserver, rather took it on the regionservers that were making the
> block count. I will take a stack trace on the offending server. Is there
> any other tool besides jstack ? I don't want to crash my regionserver.

jstack crashing the JVM is concerning but maybe off topic.

As an alternative you can poll the regionserver for a stack dump on its
infoport, e.g. http://<host>:60010/stacks

but unless the behavior you see is the _same_ regionserver asking for the
_same_ block many times consecutively, it's probably workload related.
>  To answer Vladimir's points:
> - Data access pattern definitely turns out to be uniform over a period of
> time.
> - I just did a sweep of my code base and found that there are a few places
> where Scanner are using block cache. I will disable that and see how it
> goes.

Please let us know how it goes.
Best regards,

   - Andy

Problems worthy of attack prove their worth by hitting back. - Piet Hein
(via Tom White)