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Alan Gates commented on PIG-2417: --------------------------------- Jeremy, For the patch to apply in an SVN environment, you need to generate it with 'git diff --no-prefix'. > Streaming UDFs - allow users to easily write UDFs in scripting languages > with no JVM implementation. > ----------------------------------------------------------------------------------------------------- > > Key: PIG-2417 > URL: https://issues.apache.org/jira/browse/PIG-2417 > Project: Pig > Issue Type: Improvement > Affects Versions: 0.11 > Reporter: Jeremy Karn > Attachments: python_streaming_string.patch > > > The goal of Streaming UDFs is to allow users to easily write UDFs in > scripting languages with no JVM implementation or a limited JVM > implementation. The initial proposal is outlined here: > https://cwiki.apache.org/confluence/display/PIG/StreamingUDFs. > In order to implement this we need new syntax to distinguish a streaming UDF > from an embedded JVM UDF. I'd propose something like the following (although > I'm not sure 'language' is the best term to be using): > {code}define my_streaming_udfs language('python') > ship('my_streaming_udfs.py'){code} > We'll also need a language-specific controller script that gets shipped to > the cluster which is responsible for reading the input stream, deserializing > the input data, passing it to the user written script, serializing that > script output, and writing that to the output stream. > Finally, we'll need to add a StreamingUDF class that extends evalFunc. This > class will likely share some of the existing code in POStream and > ExecutableManager (where it make sense to pull out shared code) to stream > data to/from the controller script. > One alternative approach to creating the StreamingUDF EvalFunc is to use the > POStream operator directly. This would involve inserting the POStream > operator instead of the POUserFunc operator whenever we encountered a > streaming UDF while building the physical plan. This approach seemed > problematic because there would need to be a lot of changes in order to > support POStream in all of the places we want to be able use UDFs (For > example - to operate on a single field inside of a for each statement). -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira