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From sreejesh s <sreejesh...@yahoo.com>
Subject Avoiding skew and determining optimal number of mappers in SQOOP import.
Date Sun, 21 Jun 2015 09:38:55 GMT
Hi,


 If there is a primary key on the source table, SQOOP import would generate no skewed data...
What if there is no primary key defined on the table and we have to use --split-by parameter
to split records among multiple mappers. There are high chances of skewed data depending
on the column we select to --split-by. Could you please help me understand how to avoid skewing
in such scenarios and also how to determine the optimal number of mappers to be used for any
SQOOP import.
It helps if you can explain how many mappers you have used in your use case along with the
size and format of data imported.. 
 Thanks


   
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