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https://issues.apache.org/jira/browse/PIG-5404?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17190364#comment-17190364
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Bruno Pusztahazi commented on PIG-5404:
---------------------------------------
[~thejas], [~daijy] could you please check this?
Thanks.
> FLATTEN infers wrong datatype
> -----------------------------
>
> Key: PIG-5404
> URL: https://issues.apache.org/jira/browse/PIG-5404
> Project: Pig
> Issue Type: Bug
> Components: piggybank
> Affects Versions: 0.17.0
> Reporter: Bruno Pusztahazi
> Priority: Critical
> Labels: datatypes, flatten
>
> In version 0.12 (checked out branch-0.12) the following code works as
> expected:
> With the following input file test.csv:
>
> {code:java}
> John_5,18,4.0F
> Mary_6,19,3.8F
> Bill_7,20,3.9F
> Joe_8,18,3.8F{code}
>
>
> {code:java}
> A = LOAD 'test.csv' USING PigStorage (',') AS
> (name:chararray,age:int,gpr:float);
> B = FOREACH A GENERATE FLATTEN(STRSPLIT(name,'_')) as
> (name1:chararray,name2:chararray),age,gpr;
> DESCRIBE B;{code}
> and produces the following output:
>
> {code:java}
> B: {name1: chararray,name2: chararray,age: int,gpr: float}
> {code}
> This is the expected output as the result of flatten is defined as chararrays.
>
> When using version 0.17 (checkout out branch-0.17) the code produces:
> {code:java}
> B: {name1: bytearray,name2: bytearray,age: int,gpr: float}
> {code}
> This shows that somehow FLATTEN inferred wrong data types (bytearray instead
> of chararay).
>
> Using explicit casting as a workaround on 0.17:
> {code:java}
> B1 = FOREACH B GENERATE (chararray)name1,(chararray)name2,age,gpr;
> DESCRIBE B1;{code}
> produces
> {code:java}
> B1: {name1: chararray,name2: chararray,age: int,gpr: float}
> {code}
> This time with the expected data types.
>
> The plan explain show some strange cast operators that are not really used
> (or at least the actual data types are wrong):
> {code:java}
> #-----------------------------------------------
> # New Logical Plan:
> #-----------------------------------------------
> B: (Name: LOStore Schema:
> name1#121:chararray,name2#122:chararray,age#105:int,gpr#106:float)
> |
> |---B: (Name: LOForEach Schema:
> name1#121:chararray,name2#122:chararray,age#105:int,gpr#106:float)
> | |
> | (Name: LOGenerate[false,false,false,false] Schema:
> name1#121:chararray,name2#122:chararray,age#105:int,gpr#106:float)ColumnPrune:OutputUids=[121,
> 105, 122, 106]ColumnPrune:InputUids=[121, 105, 122, 106]
> | | |
> | | (Name: Cast Type: chararray Uid: 121)
> | | |
> | | |---name1:(Name: Project Type: bytearray Uid: 121 Input: 0
> Column: 0)
> | | |
> | | (Name: Cast Type: chararray Uid: 122)
> | | |
> | | |---name2:(Name: Project Type: bytearray Uid: 122 Input: 1
> Column: 0)
> | | |
> | | age:(Name: Project Type: int Uid: 105 Input: 2 Column: 0)
> | | |
> | | gpr:(Name: Project Type: float Uid: 106 Input: 3 Column: 0)
> | |
> | |---(Name: LOInnerLoad[0] Schema: name1#121:bytearray)
> | |
> | |---(Name: LOInnerLoad[1] Schema: name2#122:bytearray)
> | |
> | |---(Name: LOInnerLoad[2] Schema: age#105:int)
> | |
> | |---(Name: LOInnerLoad[3] Schema: gpr#106:float)
> |
> |---B: (Name: LOForEach Schema:
> name1#135:bytearray,name2#136:bytearray,age#105:int,gpr#106:float)
> | |
> | (Name: LOGenerate[true,false,false] Schema:
> name1#135:bytearray,name2#136:bytearray,age#105:int,gpr#106:float)
> | | |
> | | (Name: UserFunc(org.apache.pig.builtin.STRSPLIT) Type: tuple
> Uid: 132)
> | | |
> | | |---(Name: Cast Type: chararray Uid: 104)
> | | | |
> | | | |---name:(Name: Project Type: bytearray Uid: 104 Input: 0
> Column: (*))
> | | |
> | | |---(Name: Constant Type: chararray Uid: 131)
> | | |
> | | (Name: Cast Type: int Uid: 105)
> | | |
> | | |---age:(Name: Project Type: bytearray Uid: 105 Input: 1
> Column: (*))
> | | |
> | | (Name: Cast Type: float Uid: 106)
> | | |
> | | |---gpr:(Name: Project Type: bytearray Uid: 106 Input: 2
> Column: (*))
> | |
> | |---(Name: LOInnerLoad[0] Schema: name#104:bytearray)
> | |
> | |---(Name: LOInnerLoad[1] Schema: age#105:bytearray)
> | |
> | |---(Name: LOInnerLoad[2] Schema: gpr#106:bytearray)
> |
> |---A: (Name: LOLoad Schema:
> name#104:bytearray,age#105:bytearray,gpr#106:bytearray)RequiredFields:null
> {code}
>
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