[HIVE-12619] (Parquet) Switching the field order within an array of structs causes the query to fail

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 1.1.0
• Fix Version/s: 2.1.0
• Hadoop Flags: Reviewed
• Assignee: Mohammad Islam
• Reporter: Ang Zhang
• Created: 08/Dec/15 19:56
• Updated: 21/Jun/16 15:52
• Resolved: 30/Mar/16 15:00

Description

Switching the field order within an array of structs causes the query to fail or return the wrong data for the fields, but switching the field order within just a struct works.

How to reproduce:

Case1 if the two fields have the same type, query will return wrong data for the fields

drop table if exists schema_test;
create table schema_test (msg array<struct<f1: string, f2: string>>) stored as parquet;

insert into table schema_test select stack(2, array(named_struct('f1', 'abc', 'f2', 'abc2')), array(named_struct('f1', 'efg', 'f2', 'efg2'))) from one limit 2;
select * from schema_test;
--returns
--[

{"f1":"efg","f2":"efg2"}

]
--[

{"f1":"abc","f2":"abc2"}

]

alter table schema_test change msg msg array<struct<f2: string, f1: string>>;
select * from schema_test;
--returns
--[

{"f2":"efg","f1":"efg2"}

]
--[

{"f2":"abc","f1":"abc2"}

]

Case2: if the two fields have different type, the query will fail

drop table if exists schema_test;
create table schema_test (msg array<struct<f1: string, f2: int>>) stored as parquet;

insert into table schema_test select stack(2, array(named_struct('f1', 'abc', 'f2', 1)), array(named_struct('f1', 'efg', 'f2', 2))) from one limit 2;
select * from schema_test;
--returns
--[

{"f1":"efg","f2":2}

]
--[

{"f1":"abc","f2":1}

]

alter table schema_test change msg msg array<struct<f2: int, f1: string>>;
select * from schema_test;

Failed with exception java.io.IOException:org.apache.hadoop.hive.ql.metadata.HiveException: java.lang.ClassCastException: org.apache.hadoop.io.Text cannot be cast to org.apache.hadoop.io.IntWritable