[HIVE-2329] Not using map aggregation, fails to execute group-by after cluster-by with same key

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 0.9.0
• Component/s: Query Processor
• Hadoop Flags: Reviewed
• Assignee: Navis Ryu
• Reporter: Navis Ryu
• Created: 01/Aug/11 08:48
• Updated: 30/Apr/12 21:11
• Resolved: 09/Dec/11 17:58

Description

hive.map.aggr=false
select Q1.key_int1, sum(Q1.key_int1), sum(distinct Q1.key_int1) from (select * from t1 cluster by key_int1) Q1 group by Q1.key_int1

resulted..

FAILED: Execution Error, return code 2 from org.apache.hadoop.hive.ql.exec.MapRedTask

from hadoop logs..

Caused by: java.lang.RuntimeException: cannot find field key from []
at org.apache.hadoop.hive.serde2.objectinspector.ObjectInspectorUtils.getStandardStructFieldRef(ObjectInspectorUtils.java:321)
at org.apache.hadoop.hive.serde2.objectinspector.StandardStructObjectInspector.getStructFieldRef(StandardStructObjectInspector.java:119)
at org.apache.hadoop.hive.ql.exec.ExprNodeColumnEvaluator.initialize(ExprNodeColumnEvaluator.java:82)
at org.apache.hadoop.hive.ql.exec.GroupByOperator.initializeOp(GroupByOperator.java:198)
at org.apache.hadoop.hive.ql.exec.Operator.initialize(Operator.java:357)
at org.apache.hadoop.hive.ql.exec.Operator.initialize(Operator.java:433)
........

I think the problem is caused by ReduceSinkDeDuplication, removing RS which was providing rs.key for GBY operation. If child of child RS is a GBY, we should bypass the optimization.

Issue Links

• relates to: HIVE-2732 Reduce Sink deduplication fails if the child reduce sink is followed by a join