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From anil gupta <anilgupt...@gmail.com>
Subject Re: Mapper and Reducer takes longer than usual for a HBase table aggregation task
Date Mon, 26 Aug 2013 04:08:30 GMT
Hi Pavan,

Standalone cluster? How many RS you are running?What are you trying to
achieve in MR? Have you tried increasing scanner caching?
Slow is very theoretical unless we know some more details of your stuff.


On Sun, Aug 25, 2013 at 5:52 PM, 李洪忠 <lhztop@hotmail.com> wrote:

> You need release your map code here to analyze the question. generally,
> when map/reduce hbase,  scanner with filter(s) is used. so the mapper count
> is the hbase region count in your hbase table.
> As the reason why you reduce so slow, I guess, you have an disaster join
> on the three tables, which cause too many rows.
> 于 2013/8/26 4:36, Pavan Sudheendra 写道:
>  Another Question, why does it indicate number of mappers as 1? Can i
>> change it so that multiple mappers perform computation?

Thanks & Regards,
Anil Gupta

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