A serde is actually used the other way around... Hive parses the query, writes 
MapReduce code to solve the query, and the generated code uses the serde for 
field access.

Standard way to write a serde is to start from the trunk regex serde, then 
modify as needed...

http://svn.apache.org/viewvc/hive/trunk/contrib/src/java/org/apache/hadoop/hive/contrib/serde2/RegexSerDe.java?revision=1131106&view=markup

Also, nice article by Roberto Congiu...

http://www.congiu.com/a-json-readwrite-serde-for-hive/

Chuck Connell
Nuance R&D Data Team
Burlington, MA


From: John Omernik [mailto:j...@omernik.com]
Sent: Tuesday, October 16, 2012 11:30 AM
To: user@hive.apache.org
Subject: Writing Custom Serdes for Hive

We have a maybe obvious question about a serde. When a serde in invoked, does 
it have access to the original hive query?  Ideally the original query could 
provide the Serde some hints on how to access the data on the backend.

Also, are there any good links/documention on how to write Serdes?  Kinda hard 
to google on for some reason.


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