Parquet thrift can write unions that have 0 or more than 1 set value

[asfimport]

Having 0 or more than 1 set values means the data will be unreadable in the read path, this should not be allowed in the write path.

Reporter: Alex Levenson / @isnotinvain
Assignee: Alex Levenson / @isnotinvain

Related issues:

• Tasks for parquet-mr 1.6.0 release (blocks)

_{Note: This issue was originally created as PARQUET-227. Please see the migration documentation for further details.}

[asfimport]

Ryan Blue / @rdblue:
Should we define a type annotation for unions? That way Avro, Thrift, and Hive unions could be compatible. That would also be a good opportunity to standardize behavior, so if a union has multiple non-null values we have predictable behavior for interpreting the data across object models. Obviously, this wouldn't block your work here.

[asfimport]

Alex Levenson / @isnotinvain:
Yeah that makes sense to me.

[asfimport]

Alex Levenson / @isnotinvain:
Issue resolved by pull request 153
#153