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Daniel Dai commented on PIG-4458: --------------------------------- I am fine to relax the UDF check and let user control the key order, with proper documentation. And when exception happens, can we add a message reminding user to check UDF? Also we shall add a test case with UDF. > 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)