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https://issues.apache.org/jira/browse/HIVE-15355?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16334790#comment-16334790
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Sergey Shelukhin commented on HIVE-15355:
-----------------------------------------
This bugfix seems to imply that aclStatus can change; calling
sourceStatus.getAclEntries() twice may return lists derived from different
aclStatus.
So, if ... gets some list, background thread sets aclStatus to null, so
aclEntries = ... line gets the null value.
> Concurrency issues during parallel moveFile due to HDFSUtils.setFullFileStatus
> ------------------------------------------------------------------------------
>
> Key: HIVE-15355
> URL: https://issues.apache.org/jira/browse/HIVE-15355
> Project: Hive
> Issue Type: Bug
> Affects Versions: 2.1.0, 2.2.0
> Reporter: Vihang Karajgaonkar
> Assignee: Vihang Karajgaonkar
> Priority: Major
> Fix For: 2.2.0
>
> Attachments: HIVE-15355.01.patch, HIVE-15355.02.patch
>
>
> It is possible to run into concurrency issues during multi-threaded moveFile
> issued when processing queries like {{INSERT OVERWRITE TABLE ... SELECT ..}}
> when there are multiple files in the staging directory which is a
> subdirectory of the target directory. The issue is hard to reproduce but
> following stacktrace is one such example:
> {noformat}
> INFO : Loading data to table
> functional_text_gzip.alltypesaggmultifilesnopart from
> hdfs://localhost:20500/test-warehouse/alltypesaggmultifilesnopart_text_gzip/.hive-staging_hive_2016-12-01_19-58-21_712_8968735301422943318-1/-ext-10000
> ERROR : Failed with exception java.lang.ArrayIndexOutOfBoundsException
> org.apache.hadoop.hive.ql.metadata.HiveException:
> java.lang.ArrayIndexOutOfBoundsException
> at org.apache.hadoop.hive.ql.metadata.Hive.moveFile(Hive.java:2858)
> at
> org.apache.hadoop.hive.ql.metadata.Hive.replaceFiles(Hive.java:3124)
> at org.apache.hadoop.hive.ql.metadata.Hive.loadTable(Hive.java:1701)
> at org.apache.hadoop.hive.ql.exec.MoveTask.execute(MoveTask.java:313)
> at org.apache.hadoop.hive.ql.exec.Task.executeTask(Task.java:214)
> at
> org.apache.hadoop.hive.ql.exec.TaskRunner.runSequential(TaskRunner.java:100)
> at org.apache.hadoop.hive.ql.Driver.launchTask(Driver.java:1976)
> at org.apache.hadoop.hive.ql.Driver.execute(Driver.java:1689)
> at org.apache.hadoop.hive.ql.Driver.runInternal(Driver.java:1421)
> at org.apache.hadoop.hive.ql.Driver.run(Driver.java:1205)
> at org.apache.hadoop.hive.ql.Driver.run(Driver.java:1200)
> at
> org.apache.hive.service.cli.operation.SQLOperation.runQuery(SQLOperation.java:237)
> at
> org.apache.hive.service.cli.operation.SQLOperation.access$300(SQLOperation.java:88)
> at
> org.apache.hive.service.cli.operation.SQLOperation$3$1.run(SQLOperation.java:293)
> 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:1796)
> Getting log thread is interrupted, since query is done!
> at
> org.apache.hive.service.cli.operation.SQLOperation$3.run(SQLOperation.java:306)
> at
> java.util.concurrent.Executors$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$Worker.run(ThreadPoolExecutor.java:615)
> at java.lang.Thread.run(Thread.java:745)
> Caused by: java.lang.ArrayIndexOutOfBoundsException
> at java.lang.System.arraycopy(Native Method)
> at java.util.ArrayList.removeRange(ArrayList.java:616)
> at java.util.ArrayList$SubList.removeRange(ArrayList.java:1021)
> at java.util.AbstractList.clear(AbstractList.java:234)
> at
> com.google.common.collect.Iterables.removeIfFromRandomAccessList(Iterables.java:213)
> at com.google.common.collect.Iterables.removeIf(Iterables.java:184)
> at
> org.apache.hadoop.hive.shims.Hadoop23Shims.removeBaseAclEntries(Hadoop23Shims.java:865)
> at
> org.apache.hadoop.hive.shims.Hadoop23Shims.setFullFileStatus(Hadoop23Shims.java:757)
> at org.apache.hadoop.hive.ql.metadata.Hive$3.call(Hive.java:2835)
> at org.apache.hadoop.hive.ql.metadata.Hive$3.call(Hive.java:2828)
> ... 4 more
> ERROR : FAILED: Execution Error, return code 1 from
> org.apache.hadoop.hive.ql.exec.MoveTask
> {noformat}
> Quick online search also shows some other instances like the one mentioned in
> http://stackoverflow.com/questions/38900333/get-concurrentmodificationexception-in-step-2-create-intermediate-flat-hive-tab
> The issue seems to be coming from the below code :
> {code}
> if (aclEnabled) {
> aclStatus = sourceStatus.getAclStatus();
> if (aclStatus != null) {
> LOG.trace(aclStatus.toString());
> aclEntries = aclStatus.getEntries();
> removeBaseAclEntries(aclEntries);
> //the ACL api's also expect the tradition user/group/other permission
> in the form of ACL
> aclEntries.add(newAclEntry(AclEntryScope.ACCESS, AclEntryType.USER,
> sourcePerm.getUserAction()));
> aclEntries.add(newAclEntry(AclEntryScope.ACCESS, AclEntryType.GROUP,
> sourcePerm.getGroupAction()));
> aclEntries.add(newAclEntry(AclEntryScope.ACCESS, AclEntryType.OTHER,
> sourcePerm.getOtherAction()));
> }
> }
> {code}
> removeBaseAclEntries removes objects from {{List<AclEntry> aclEntries}} When
> HDFSUtils.setFullFileStatus() method is called from multiple threads like
> from
> https://github.com/apache/hive/blob/master/ql/src/java/org/apache/hadoop/hive/ql/metadata/Hive.java#L2835
> it is possible that multiple threads try to modify the {{List<AclEntry>
> aclEntries}} leading to concurrency issues.
> We should either move that block into a thread-safe region or call
> setFullFileStatus when all the threads converge.
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