Hi Ritesh To help u get started , I am writing a simple HelloWorld-ish UDF that might help…If it doesn't please ask for more clarifications...
Good Luck Thanks sanjay ******************************************************************************** ToUpperCase.java package com.sanjaysubramanian.utils.hive.udf; import org.apache.hadoop.hive.ql.exec.UDF; public final class ToUpperCase extends UDF{ protected final Log logger = LogFactory.getLog(toUpperCase.class); public String evaluate(final String inputString) { if (inputString != null){ return inputString.toUpper; } else { return inputString; } } } ******************************************************************************** Usage in a Hive script hive -e " create temporary function toupper as 'com.sanjaysubramanian.utils.hive.udf.ToUpperCase'; SELECT first_name, toupper(first_name) FROM company_names " *********************************************************************************** From: Ritesh Agrawal <ragra...@netflix.com<mailto:ragra...@netflix.com>> Reply-To: "user@hive.apache.org<mailto:user@hive.apache.org>" <user@hive.apache.org<mailto:user@hive.apache.org>> Date: Monday, August 5, 2013 9:41 AM To: "user@hive.apache.org<mailto:user@hive.apache.org>" <user@hive.apache.org<mailto:user@hive.apache.org>> Subject: Re: Hive UDAF extending UDAF class: iterate or evaluate method Hi Lefty, I used the wiki you sent to write my first version of UDAF. However, I found it to be utterly complex, especially for storing partial results as I am not very familiar with hive API. Then I found another example of UDAF in the hadoop the definitive guide book and it had much simpler code but using different method. Instead of using iterate it was using evaluate method and so I am getting confused. Ritesh On Sun, Aug 4, 2013 at 2:18 PM, Lefty Leverenz <leftylever...@gmail.com<mailto:leftylever...@gmail.com>> wrote: You might find this wikidoc useful: GenericUDAFCaseStudy<https://cwiki.apache.org/confluence/display/Hive/GenericUDAFCaseStudy>. The O'Reilly book "Programming Hive" also has a section called "User-Defined Aggregate Functions" in chapter 13 (Functions), pages 172 to 176. -- Lefty On Sun, Aug 4, 2013 at 7:12 AM, Ritesh Agrawal <ragra...@netflix.com<mailto:ragra...@netflix.com>> wrote: Hi all, I am trying to write a UDAF function. I found an example that shows how to implement a UDAF in "Hadoop The Definitive Guide" book. However I am little confused. In the book, the author extends UDAF class and implements init, iterate, terminatePartial, merge and terminate function. However looking at the hive docs (http://hive.apache.org/docs/r0.11.0/api/org/apache/hadoop/hive/ql/exec/UDAF.html), it seems I need to implement init, aggregate, evaluatePartial, aggregatePartial and evaluate function. Please let me know what are the write functions to implement. Ritesh -- Lefty 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.