[
https://issues.apache.org/jira/browse/PIG-4458?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14360700#comment-14360700
]
Daniel Dai commented on PIG-4458:
---------------------------------
Yes, I know what your patch doing. The user now has the responsibility to make
sure UDF does not change the position of the order key. This should be a
document item now, and when exception happen, we'd better give a reminder. And
we need a test case since we enables a new use case which is never tested
before.
> Support UDFs in a FOREACH Before a Merge Join
> ---------------------------------------------
>
> Key: PIG-4458
> URL: https://issues.apache.org/jira/browse/PIG-4458
> Project: Pig
> Issue Type: New Feature
> Reporter: William Watson
> Attachments: remove_merge_join_udf_restriction.patch
>
>
> Right now, the MapSideMergeValidator outright rejects any foreach that has a
> UDF in it:
> {code}
> private boolean isAcceptableForEachOp(Operator lo) throws
> LogicalToPhysicalTranslatorException {
> if (lo instanceof LOForEach) {
> OperatorPlan innerPlan = ((LOForEach) lo).getInnerPlan();
> validateMapSideMerge(innerPlan.getSinks(), innerPlan);
> return !containsUDFs((LOForEach) lo);
> } else {
> return false;
> }
> }
> {code}
> There is a TODO for this later on in that same class (inside containsUDFs):
> {code}
> // TODO (dvryaboy): in the future we could relax this rule by tracing what
> fields
> // are being passed into the UDF, and only refusing if the UDF is working on
> the
> // join key. Transforms of other fields should be ok.
> {code}
> We should do the TODO and relax this requirement or just remove it altogether
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
