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Hadoop >> mail # user >> Distributed table processing is slower that local table processing

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Re: Distributed table processing is slower that local table processing
Hi Alexander,

Is data properly distributed over the cluster in Distributed Mode? If the
data is not then you wont get good results in distributed mode.

Anil Gupta

On Thu, Mar 29, 2012 at 8:37 AM, Alexander Goryunov <[EMAIL PROTECTED]>wrote:

> Hello,
> I'm running 3 data node cluster (8core Xeon, 16G) + 1 node for jobtracker
> and namenode with Hadoop and HBase and have strange performance results.
> The same map job runs with speed about 300 000 records per second for 1
> node table and 100 000 records per second for table  distributed to 3
> nodes.
> Scan caching is 1000, each row is about 0.2K, compression is off,
> setCacheBlock is false.
> 7 map tasks in parallel for each node. (281 for the big table in summary
> and 16 for the small table)
> Map job reads some sequential data and writes down a few from it. No reduce
> tasks are set for this job.
> Both table have the same data and have sizes about 10M (first one) records
> and 150M (second one) records.
> Do you have any idea what could be the reason of such behavior?
> Thanks.

Thanks & Regards,
Anil Gupta