[HIVE-2732] Reduce Sink deduplication fails if the child reduce sink is followed by a join

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.10.0
• Fix Version/s: 0.10.0
• Component/s: Query Processor
• Hadoop Flags: Reviewed
• Assignee: Navis Ryu
• Reporter: Kevin Wilfong
• Created: 21/Jan/12 00:44
• Updated: 10/Jan/13 19:53
• Resolved: 15/May/12 20:06

Description

set hive.optimize.reducededuplication=true;
set hive.auto.convert.join=true;
explain select * from (select * from src distribute by key sort by key) a join src b on a.key = b.key;

fails with the following exception

java.lang.ClassCastException: org.apache.hadoop.hive.ql.exec.SelectOperator cannot be cast to org.apache.hadoop.hive.ql.exec.ReduceSinkOperator
at org.apache.hadoop.hive.ql.optimizer.MapJoinProcessor.convertMapJoin(MapJoinProcessor.java:313)
at org.apache.hadoop.hive.ql.optimizer.MapJoinProcessor.genMapJoinOpAndLocalWork(MapJoinProcessor.java:226)
at org.apache.hadoop.hive.ql.optimizer.physical.CommonJoinResolver$CommonJoinTaskDispatcher.processCurrentTask(CommonJoinResolver.java:174)
at org.apache.hadoop.hive.ql.optimizer.physical.CommonJoinResolver$CommonJoinTaskDispatcher.dispatch(CommonJoinResolver.java:287)
at org.apache.hadoop.hive.ql.lib.TaskGraphWalker.dispatch(TaskGraphWalker.java:111)
at org.apache.hadoop.hive.ql.lib.TaskGraphWalker.walk(TaskGraphWalker.java:194)
at org.apache.hadoop.hive.ql.lib.TaskGraphWalker.startWalking(TaskGraphWalker.java:139)
at org.apache.hadoop.hive.ql.optimizer.physical.CommonJoinResolver.resolve(CommonJoinResolver.java:68)
at org.apache.hadoop.hive.ql.optimizer.physical.PhysicalOptimizer.optimize(PhysicalOptimizer.java:72)
at org.apache.hadoop.hive.ql.parse.SemanticAnalyzer.genMapRedTasks(SemanticAnalyzer.java:7019)
at org.apache.hadoop.hive.ql.parse.SemanticAnalyzer.analyzeInternal(SemanticAnalyzer.java:7312)
at org.apache.hadoop.hive.ql.parse.BaseSemanticAnalyzer.analyze(BaseSemanticAnalyzer.java:243)
at org.apache.hadoop.hive.ql.parse.ExplainSemanticAnalyzer.analyzeInternal(ExplainSemanticAnalyzer.java:48)
at org.apache.hadoop.hive.ql.parse.BaseSemanticAnalyzer.analyze(BaseSemanticAnalyzer.java:243)
at org.apache.hadoop.hive.ql.Driver.compile(Driver.java:430)
at org.apache.hadoop.hive.ql.Driver.compile(Driver.java:337)
at org.apache.hadoop.hive.ql.Driver.run(Driver.java:889)
at org.apache.hadoop.hive.cli.CliDriver.processLocalCmd(CliDriver.java:255)
at org.apache.hadoop.hive.cli.CliDriver.processCmd(CliDriver.java:212)
at org.apache.hadoop.hive.cli.CliDriver.processLine(CliDriver.java:403)
at org.apache.hadoop.hive.cli.CliDriver.run(CliDriver.java:671)
at org.apache.hadoop.hive.cli.CliDriver.main(CliDriver.java:554)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.hadoop.util.RunJar.main(RunJar.java:156)

If hive.auto.convert.join is set to false, it produces an incorrect plan where the two halves of the join are processed in two separate map reduce tasks, and the reducers of these two tasks both contain the join operator resulting in an exception.

Issue Links

• is related to: HIVE-2329 Not using map aggregation, fails to execute group-by after cluster-by with same key