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From Vaibhav Jain <vaibhav.jain...@gmail.com>
Subject Will this UDF always execute on a single reducer ?
Date Sat, 01 Mar 2014 03:56:58 GMT
Hi,

I have written a custom UDF that I want to be executed on a single reducer
when I am using it in a query. Following is the the query  and  I want to
confirm whether this would always always execute the UDF on a single
reducer (assuming the ORDER BY would send all the rows  to a single
reducer):


*SELECT UDF(<col>) AS alias  from *

*( SELECT <col> *

*  FROM  <table> TABLESAMPLE (x PERCENT) *

*  ORDER BY <col> )*

*ORDER BY alias;*


Is it a possibility that the UDF is executed on a mapper?

-- 
Thanks
Vaibhav Jain

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