zhihai xu created HIVE-14303:
--------------------------------
Summary: CommonJoinOperator.checkAndGenObject should return
directly in CLOSE state to avoid NPE if ExecReducer.close is called twice.
Key: HIVE-14303
URL: https://issues.apache.org/jira/browse/HIVE-14303
Project: Hive
Issue Type: Bug
Reporter: zhihai xu
Assignee: zhihai xu
Fix For: 2.1.0
CommonJoinOperator.checkAndGenObject should return directly in CLOSE state to
avoid NPE if ExecReducer.close is called twice. ExecReducer.close implements
Closeable interface and ExecReducer.close can be called multiple time. We saw
the following NPE which hide the real exception due to this bug.
{code}
Error: java.lang.RuntimeException: Hive Runtime Error while closing operators:
null
at
org.apache.hadoop.hive.ql.exec.mr.ExecReducer.close(ExecReducer.java:296)
at org.apache.hadoop.io.IOUtils.cleanup(IOUtils.java:244)
at
org.apache.hadoop.mapred.ReduceTask.runOldReducer(ReduceTask.java:459)
at org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:392)
at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:163)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:415)
at
org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1671)
at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:158)
Caused by: java.lang.NullPointerException
at
org.apache.hadoop.hive.ql.exec.CommonJoinOperator.checkAndGenObject(CommonJoinOperator.java:718)
at
org.apache.hadoop.hive.ql.exec.JoinOperator.endGroup(JoinOperator.java:256)
at
org.apache.hadoop.hive.ql.exec.mr.ExecReducer.close(ExecReducer.java:284)
... 8 more
{code}
The code from ReduceTask.runOldReducer:
{code}
reducer.close(); //line 453
reducer = null;
out.close(reporter);
out = null;
} finally {
IOUtils.cleanup(LOG, reducer);// line 459
closeQuietly(out, reporter);
}
{code}
Based on the above stack trace and code, reducer.close() is called twice
because the exception happened when reducer.close() is called for the first
time at line 453, the code exit before reducer was set to null.
NullPointerException is triggered when reducer.close() is called for the second
time in IOUtils.cleanup. NullPointerException hide the real exception which
happened when reducer.close() is called for the first time at line 453.
The reason for NPE is:
The first reducer.close called CommonJoinOperator.closeOp which clear
{{storage}}
{code}
Arrays.fill(storage, null);
{code}
the second reduce.close generated NPE due to null {{storage[alias]}} which is
set to null by first reducer.close.
The following reducer log can give more proof:
{code}
2016-07-14 22:24:51,016 INFO [main]
org.apache.hadoop.hive.ql.exec.JoinOperator: 0 finished. closing...
2016-07-14 22:24:51,016 INFO [main]
org.apache.hadoop.hive.ql.exec.JoinOperator: 0 finished. closing...
2016-07-14 22:24:51,016 INFO [main]
org.apache.hadoop.hive.ql.exec.JoinOperator: SKEWJOINFOLLOWUPJOBS:0
2016-07-14 22:24:51,016 INFO [main]
org.apache.hadoop.hive.ql.exec.SelectOperator: 1 finished. closing...
2016-07-14 22:24:51,016 INFO [main]
org.apache.hadoop.hive.ql.exec.SelectOperator: 2 finished. closing...
2016-07-14 22:24:51,016 INFO [main]
org.apache.hadoop.hive.ql.exec.SelectOperator: 3 finished. closing...
2016-07-14 22:24:51,016 INFO [main]
org.apache.hadoop.hive.ql.exec.FileSinkOperator: 4 finished. closing...
2016-07-14 22:24:51,016 INFO [main]
org.apache.hadoop.hive.ql.exec.FileSinkOperator: FS[4]: records written - 53466
2016-07-14 22:25:11,555 ERROR [main] ExecReducer: Hit error while closing
operators - failing tree
2016-07-14 22:25:11,649 WARN [main] org.apache.hadoop.mapred.YarnChild:
Exception running child : java.lang.RuntimeException: Hive Runtime Error while
closing operators: null
at
org.apache.hadoop.hive.ql.exec.mr.ExecReducer.close(ExecReducer.java:296)
at org.apache.hadoop.io.IOUtils.cleanup(IOUtils.java:244)
at
org.apache.hadoop.mapred.ReduceTask.runOldReducer(ReduceTask.java:459)
at org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:392)
at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:163)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:415)
at
org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1671)
at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:158)
Caused by: java.lang.NullPointerException
at
org.apache.hadoop.hive.ql.exec.CommonJoinOperator.checkAndGenObject(CommonJoinOperator.java:718)
at
org.apache.hadoop.hive.ql.exec.JoinOperator.endGroup(JoinOperator.java:256)
at
org.apache.hadoop.hive.ql.exec.mr.ExecReducer.close(ExecReducer.java:284)
... 8 more
{code}
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