[HIVE-10538] Fix NPE in FileSinkOperator from hashcode mismatch

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 1.0.0, 1.2.0
• Fix Version/s: 1.3.0, 2.0.0
• Component/s: Query Processor
• Assignee: Peter Slawski
• Reporter: Peter Slawski
• Created: 29/Apr/15 20:06
• Updated: 05/Jun/15 21:50
• Resolved: 07/May/15 20:48

Description

A Null Pointer Exception occurs when in FileSinkOperator when using bucketed tables and distribute by with multiFileSpray enabled. The following snippet query reproduces this issue:

set hive.enforce.bucketing = true;
set hive.exec.reducers.max = 20;

create table bucket_a(key int, value_a string) clustered by (key) into 256 buckets;
create table bucket_b(key int, value_b string) clustered by (key) into 256 buckets;
create table bucket_ab(key int, value_a string, value_b string) clustered by (key) into 256 buckets;

-- Insert data into bucket_a and bucket_b

insert overwrite table bucket_ab
select a.key, a.value_a, b.value_b from bucket_a a join bucket_b b on (a.key = b.key) distribute by key;

The following stack trace is logged.

2015-04-29 12:54:12,841 FATAL [pool-110-thread-1]: ExecReducer (ExecReducer.java:reduce(255)) - org.apache.hadoop.hive.ql.metadata.HiveException: Hive Runtime Error while processing row (tag=0) {"key":{},"value":{"_col0":"113","_col1":"val_113"}}
	at org.apache.hadoop.hive.ql.exec.mr.ExecReducer.reduce(ExecReducer.java:244)
	at org.apache.hadoop.mapred.ReduceTask.runOldReducer(ReduceTask.java:444)
	at org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:392)
	at org.apache.hadoop.mapred.LocalJobRunner$Job$ReduceTaskRunnable.run(LocalJobRunner.java:319)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
	at java.util.concurrent.FutureTask.run(FutureTask.java:262)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NullPointerException
	at org.apache.hadoop.hive.ql.exec.FileSinkOperator.findWriterOffset(FileSinkOperator.java:819)
	at org.apache.hadoop.hive.ql.exec.FileSinkOperator.process(FileSinkOperator.java:747)
	at org.apache.hadoop.hive.ql.exec.Operator.forward(Operator.java:837)
	at org.apache.hadoop.hive.ql.exec.SelectOperator.process(SelectOperator.java:88)
	at org.apache.hadoop.hive.ql.exec.mr.ExecReducer.reduce(ExecReducer.java:235)
	... 8 more