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From "Nagarjuna Kanamarlapudi" <>
Subject Re: UDFs and Thread Safety?
Date Mon, 11 Mar 2013 03:51:20 GMT
Yes , in a map only query your udf will be executed at the mapper side.

I don't know how you can make your udf thread safe.  But what I do set the number of reducers
to 1 and make sure that I write a query which has both map and reduce. 
Then the udf will be executed at the reduce phase and suffice my requirement . 
Sent from  iPhone

On Mon, Mar 11, 2013 at 8:43 AM, Shaun Clowes <>

> Hi All,
> Could anyone describe what the required thread safety for a UDF is? I
> understand that one is instantiated for each use of the function in an
> expression, but can there be multiple threads executing the methods of a
> single UDF object at once?
> Thanks,
> Shaun
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