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Date: Sun, 10 Mar 2013 20:51:20 -0700 (PDT)
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From: "Nagarjuna Kanamarlapudi" <nagarjuna.kanamarlapudi@gmail.com>
To: user@hive.apache.org
Cc: user@hive.apache.org
Subject: Re: UDFs and Thread Safety?
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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. =C2=A0But what I do set=
 the number of reducers to 1 and make sure that I write a query which has =
both map and reduce.=C2=A0
Then the udf will be executed at the reduce phase and suffice my =
requirement .=C2=A0
=E2=80=94
Sent from  iPhone

On Mon, Mar 11, 2013 at 8:43 AM, Shaun Clowes <sclowes@atlassian.com>
wrote:

> Hi All,
> Could anyone describe what the required thread safety for a UDF is=3F 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=3F
> Thanks,
> Shaun
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<p>Yes , in a map only query your udf will be executed at the mapper side.=
</p><div><br></div><div>I don't know how you can make your udf thread safe.=
 =C2=A0But what I do set the number of reducers to 1 and make sure that I =
write a query which has both map and reduce.=C2=A0</div><div>Then the udf =
will be executed at the reduce phase and suffice my requirement .=
=C2=A0</div><div class=3D=22mailbox=5Fsignature=22>=E2=80=94<br>Sent from  =
iPhone</div><br><br><div class=3D=22gmail=5Fquote=22><p>On Mon, Mar 11, =
2013 at 8:43 AM, Shaun Clowes <span dir=3D=22ltr=22>&lt;<a =
href=3D=22mailto:sclowes@atlassian.com=22 target=3D=22=5Fblank=22>sclowes@a=
tlassian.com</a>&gt;</span> wrote:<br></p><blockquote =
class=3D=22gmail=5Fquote=22 style=3D=22margin:0 0 0 .8ex;border-left:1px =
#ccc solid;padding-left:1ex;=22><div dir=3D=22ltr=22>Hi All,=
=C2=A0<div><br></div><div style=3D=22=22>Could anyone describe what the =
required thread safety for a UDF is=3F 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=3F=C2=A0</div>

<div style=3D=22=22><br></div><div style=3D=22=22>Thanks,</div><div =
style=3D=22=22>Shaun</div></div></blockquote></div><br>
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