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From Stack <st...@duboce.net>
Subject Re: Question on hbase.client.scanner.timeout.period
Date Tue, 25 Aug 2015 04:06:43 GMT
On Mon, Aug 24, 2015 at 4:48 PM, Eric Owhadi <eric.owhadi@esgyn.com> wrote:

> Hello everyone,
> We have been facing a situation on trafodion, where we are hitting the
> hbase.client.scanner.timeout.period scenario:
> basically, when doing queries that require spilling to disk because of high
> complexity of what is involved, the underlying hbase scanner serving one of
> the operation involved in the complex query cannot call the next() withing
> the timeout specify... too busy taking care of other business.
> This is legit scenario, and I was wondering why in the code, special care
> is done to make sure that client side, if a DNRIOE of type
> unknownScannerException shows up, and the
> hbase.client.scanner.timeout.period time elapsed, we make sure to throw a
> scannerTimeoutException, instead of just let it go and reset scanner.
>
> Scanners were redone in hbase 1.1. Can Trafodion come up onto hbase 1.1?
See https://blogs.apache.org/hbase/entry/scan_improvements_in_hbase_1 for
summary.
St.Ack



> I imagine that the lease time out implementation on region server side is
> supposed to protect from resource leak of scanner object server side. But I
> am not sure why we would make it so that client side throw this timeout
> exception, when in fact what just happened was that client was too busy to
> call next() on time.
>
> I am sure there is a reason, but cannot figure it out :-).
>
> BTW, I found this JIRA, talking about exact same thing:
> https://issues.apache.org/jira/browse/HBASE-2161 but with no resolution.
>


> Any help understanding the reason of the timeout thrwown client side
> instead of an automatic reset would be much appreciated,
> Best regards,
> Eric Owhadi
>

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