Hi, If you use annotation, Hive should be able to optimize it to single call:
@UDFType(deterministic = true) The obvious condition is that it must always return the identical result when called with same parameters. Little bit more on this can be found in Mark Grovers post at http://mark.thegrovers.ca/1/post/2012/06/how-to-write-a-hive-udf.html. Regards, Jan On Tue, Jul 23, 2013 at 9:25 PM, Nitin Pawar <nitinpawar...@gmail.com>wrote: > fucntion return values are not stored for repeat use of same (as per my > understanding) > > I know you may have already thought about other approach as > > select a , if (call <-1, -1 call) as b from (select a, fooudf(a) as call > from table > > > > > On Wed, Jul 24, 2013 at 12:42 AM, Sanjay Subramanian < > sanjay.subraman...@wizecommerce.com> wrote: > >> Hi >> >> V r using version hive-exec-0.9.0-cdh4.1.2 in production >> >> I need to check and use the output from a UDF in a query to assign >> values to 2 columns in a SELECT query >> >> Example >> >> SELECT >> a, >> IF(fooUdf(a) < -1 , -1, fooUdf(a)) as b, >> IF(fooUdf(a) < -1 , fooUdf(a), 0) as c >> FROM >> my_hive_table >> >> >> So will fooUdf be called 4 times ? Or once ? >> >> Why this is important is because in our case this UDF calls a web >> service and I don't want so many calls to the service. >> >> Thanks >> >> sanjay >> >> >> >> CONFIDENTIALITY NOTICE >> ====================== >> This email message and any attachments are for the exclusive use of the >> intended recipient(s) and may contain confidential and privileged >> information. Any unauthorized review, use, disclosure or distribution is >> prohibited. If you are not the intended recipient, please contact the >> sender by reply email and destroy all copies of the original message along >> with any attachments, from your computer system. If you are the intended >> recipient, please be advised that the content of this message is subject to >> access, review and disclosure by the sender's Email System Administrator. >> > > > > -- > Nitin Pawar >
