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Can someone explain the purpose UID serves in the logical plan?Jonathan Coveney 2012-12-13, 22:17
Howdy ya'll,
I'm trying to fix the issue in this JIRA: https://issues.apache.org/jira/browse/PIG-3093 I got the plan at one point, as saw this: #----------------------------------------------- # New Logical Plan: #----------------------------------------------- D: (Name: LOForEach Schema: B::field1#4:chararray,field2#4:chararray) | | | (Name: LOGenerate[false,false] Schema: B::field1#4:chararray,field2#4:chararray) | | | | | B::field1:(Name: Project Type: chararray Uid: 4 Input: 0 Column: (*)) | | | | | A::field1:(Name: Project Type: chararray Uid: 4 Input: 1 Column: (*)) | | | |---(Name: LOInnerLoad[B::field1] Schema: B::field1#4:chararray) | | | |---(Name: LOInnerLoad[A::field1] Schema: A::field1#4:chararray) | |---C: (Name: LOJoin(HASH) Schema: A::field1#4:chararray,B::field1#4:chararray) | | | field1:(Name: Project Type: chararray Uid: 4 Input: 0 Column: field1) | | | field1:(Name: Project Type: chararray Uid: 4 Input: 1 Column: field1) | |---A: (Name: LOLoad Schema: field1#4:chararray)RequiredFields:null | |---B: (Name: LOForEach Schema: field1#4:chararray) | | | (Name: LOGenerate[false] Schema: field1#4:chararray) | | | | | field1:(Name: Project Type: chararray Uid: 4 Input: 0 Column: (*)) | | | |---(Name: LOInnerLoad[0] Schema: field1#4:chararray) | |---A: (Name: LOLoad Schema: field1#4:chararray)RequiredFields:null Noting that the Uid is repeated (because the 2 fields are derived from the same field). I'm not sure if this is the source of the error, but since I do not yet know what the error is I thought I would ask about it, as I do not well understand the role of the uid, but it comes up a lot in the LogicalPlan. Thank you! Jon |