Santhosh Srinivasan commented on PIG-577:

The use of the null constant in the bincond in the context of a flatten should 
handle the following cases:

Assumption: one of the columns in the bincond is a null constant.

1. If the other column is a simple type or a map then cast the null to the 
other type.
2. If the other column is a complex type other than a map then remove the null 
constant and supplant it with 
a bag or a tuple or a map constant with the appropriate elements, i.e., if the 
other column
is a bag with a tuple that contains three columns (say int, float, chararray) 
then replace the
null constant with a bag that contains a tuple with three null constants. The 
same reasoning
applies to a tuple column.

Upon flattening the complex types will give out the appropriate number of 

Handling null constants for complex type has implications when the constant is 
materialized either
via dump or store. If the null constant is replaced with an appropriate 
bag/tuple/map then the materialized
constant will look like {(,,)} or (,,) or []. This conflicts with our existing 
view of nulls being empty when

> outer join query looses name information
> ----------------------------------------
>                 Key: PIG-577
>                 URL: https://issues.apache.org/jira/browse/PIG-577
>             Project: Pig
>          Issue Type: Bug
>    Affects Versions: types_branch
>            Reporter: Olga Natkovich
>             Fix For: types_branch
> The following query:
> A = LOAD 'student_data' AS (name: chararray, age: int, gpa: float);
> B = LOAD 'voter_data' AS (name: chararray, age: int, registration: chararray, 
> contributions: float);
> C = COGROUP A BY name, B BY name;
> D = FOREACH C GENERATE group, flatten((IsEmpty(A) ? null : A)), 
> flatten((IsEmpty(B) ? null : B));
> describe D;
> E = FOREACH D GENERATE A::gpa, B::contributions;
> Give the following error: (Even though describe shows correct information: D: 
> {group: chararray,A::name: chararray,A::age: int,A::gpa: float,B::name: 
> chararray,B::age: int,B::registration: chararray,B::contributions: float}
> java.io.IOException: Invalid alias: A::gpa in {group: 
> chararray,bytearray,bytearray}
>         at org.apache.pig.PigServer.parseQuery(PigServer.java:298)
>         at org.apache.pig.PigServer.registerQuery(PigServer.java:263)
>         at 
> org.apache.pig.tools.grunt.GruntParser.processPig(GruntParser.java:439)
>         at 
> org.apache.pig.tools.pigscript.parser.PigScriptParser.parse(PigScriptParser.java:249)
>         at 
> org.apache.pig.tools.grunt.GruntParser.parseStopOnError(GruntParser.java:84)
>         at org.apache.pig.tools.grunt.Grunt.exec(Grunt.java:64)
>         at org.apache.pig.Main.main(Main.java:306)
> Caused by: org.apache.pig.impl.logicalLayer.parser.ParseException: Invalid 
> alias: A::gpa in {group: chararray,bytearray,bytearray}
>         at 
> org.apache.pig.impl.logicalLayer.parser.QueryParser.AliasFieldOrSpec(QueryParser.java:5930)
>         at 
> org.apache.pig.impl.logicalLayer.parser.QueryParser.ColOrSpec(QueryParser.java:5788)
>         at 
> org.apache.pig.impl.logicalLayer.parser.QueryParser.BaseEvalSpec(QueryParser.java:3974)
>         at 
> org.apache.pig.impl.logicalLayer.parser.QueryParser.UnaryExpr(QueryParser.java:3871)
>         at 
> org.apache.pig.impl.logicalLayer.parser.QueryParser.CastExpr(QueryParser.java:3825)
>         at 
> org.apache.pig.impl.logicalLayer.parser.QueryParser.MultiplicativeExpr(QueryParser.java:3734)
>         at 
> org.apache.pig.impl.logicalLayer.parser.QueryParser.AdditiveExpr(QueryParser.java:3660)
>         at 
> org.apache.pig.impl.logicalLayer.parser.QueryParser.InfixExpr(QueryParser.java:3626)
>         at 
> org.apache.pig.impl.logicalLayer.parser.QueryParser.FlattenedGenerateItem(QueryParser.java:3552)
>         at 
> org.apache.pig.impl.logicalLayer.parser.QueryParser.FlattenedGenerateItemList(QueryParser.java:3462)
>         at 
> org.apache.pig.impl.logicalLayer.parser.QueryParser.GenerateStatement(QueryParser.java:3419)
>         at 
> org.apache.pig.impl.logicalLayer.parser.QueryParser.NestedBlock(QueryParser.java:2894)
>         at 
> org.apache.pig.impl.logicalLayer.parser.QueryParser.ForEachClause(QueryParser.java:2309)
>         at 
> org.apache.pig.impl.logicalLayer.parser.QueryParser.BaseExpr(QueryParser.java:966)
>         at 
> org.apache.pig.impl.logicalLayer.parser.QueryParser.Expr(QueryParser.java:742)
>         at 
> org.apache.pig.impl.logicalLayer.parser.QueryParser.Parse(QueryParser.java:537)
>         at 
> org.apache.pig.impl.logicalLayer.LogicalPlanBuilder.parse(LogicalPlanBuilder.java:60)
>         at org.apache.pig.PigServer.parseQuery(PigServer.java:295)
>         ... 6 more

This message is automatically generated by JIRA.
You can reply to this email to add a comment to the issue online.

Reply via email to