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https://issues.apache.org/jira/browse/TEZ-3284?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15349010#comment-15349010
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Jonathan Eagles commented on TEZ-3284:
--------------------------------------
I have tested this for sanity tests only. I will want to verify correctness and
performance before this goes in. Will update when I get numbers.
> Synchronization for every write in UnorderdKVWriter
> ---------------------------------------------------
>
> Key: TEZ-3284
> URL: https://issues.apache.org/jira/browse/TEZ-3284
> Project: Apache Tez
> Issue Type: Bug
> Affects Versions: 0.9.0
> Reporter: Gopal V
> Priority: Critical
> Labels: Performance
> Attachments: TEZ-3284.1.patch, TEZ-3284.2.patch
>
>
> {code}
> baos = new ByteArrayOutputStream();
> dos = new DataOutputStream(baos);
> keySerializer.open(dos);
> valSerializer.open(dos);
> {code}
> This is a known performance issue as documented in HADOOP-10694
> Both ByteArrayOutputStream::write() and DataOutputStream::write() have lock
> prefix calls in them, because they are object synchronized methods.
> Recommended solution is to replicate the Hive NonSync impls similar to
> HADOOP-10694
> {code}
> TezTaskRunner [RUNNABLE]
> *** java.io.DataOutputStream.write(byte[], int, int) DataOutputStream.java:107
> org.apache.tez.runtime.library.common.serializer.TezBytesWritableSerialization$TezBytesWritableSerializer.serialize(Writable)
> TezBytesWritableSerialization.java:123
> org.apache.tez.runtime.library.common.serializer.TezBytesWritableSerialization$TezBytesWritableSerializer.serialize(Object)
> TezBytesWritableSerialization.java:110
> org.apache.tez.runtime.library.common.writers.UnorderedPartitionedKVWriter.write(Object,
> Object, int) UnorderedPartitionedKVWriter.java:295
> org.apache.tez.runtime.library.common.writers.UnorderedPartitionedKVWriter.write(Object,
> Object) UnorderedPartitionedKVWriter.java:257
> org.apache.hadoop.hive.ql.exec.tez.TezProcessor$TezKVOutputCollector.collect(Object,
> Object) TezProcessor.java:232
> org.apache.hadoop.hive.ql.exec.vector.reducesink.VectorReduceSinkCommonOperator.collect(BytesWritable,
> Writable) VectorReduceSinkCommonOperator.java:432
> org.apache.hadoop.hive.ql.exec.vector.reducesink.VectorReduceSinkCommonOperator.process(Object,
> int) VectorReduceSinkCommonOperator.java:397
> org.apache.hadoop.hive.ql.exec.Operator.forward(Object, ObjectInspector)
> Operator.java:837
> org.apache.hadoop.hive.ql.exec.vector.VectorSelectOperator.process(Object,
> int) VectorSelectOperator.java:144
> org.apache.hadoop.hive.ql.exec.Operator.forward(Object, ObjectInspector)
> Operator.java:837
> org.apache.hadoop.hive.ql.exec.vector.VectorFilterOperator.process(Object,
> int) VectorFilterOperator.java:121
> org.apache.hadoop.hive.ql.exec.Operator.forward(Object, ObjectInspector)
> Operator.java:837
> org.apache.hadoop.hive.ql.exec.TableScanOperator.process(Object, int)
> TableScanOperator.java:130
> org.apache.hadoop.hive.ql.exec.vector.VectorMapOperator.process(Writable)
> VectorMapOperator.java:796
> org.apache.hadoop.hive.ql.exec.tez.MapRecordSource.processRow(Object)
> MapRecordSource.java:86
> org.apache.hadoop.hive.ql.exec.tez.MapRecordSource.pushRecord()
> MapRecordSource.java:70
> org.apache.hadoop.hive.ql.exec.tez.MapRecordProcessor.run()
> MapRecordProcessor.java:361
> org.apache.hadoop.hive.ql.exec.tez.TezProcessor.initializeAndRunProcessor(Map,
> Map) TezProcessor.java:172
> org.apache.hadoop.hive.ql.exec.tez.TezProcessor.run(Map, Map)
> TezProcessor.java:160
> org.apache.tez.runtime.LogicalIOProcessorRuntimeTask.run()
> LogicalIOProcessorRuntimeTask.java:370
> org.apache.tez.runtime.task.TaskRunner2Callable$1.run()
> TaskRunner2Callable.java:73
> org.apache.tez.runtime.task.TaskRunner2Callable$1.run()
> TaskRunner2Callable.java:61
> java.security.AccessController.doPrivileged(PrivilegedExceptionAction,
> AccessControlContext) AccessController.java (native)
> javax.security.auth.Subject.doAs(Subject, PrivilegedExceptionAction)
> Subject.java:422
> org.apache.hadoop.security.UserGroupInformation.doAs(PrivilegedExceptionAction)
> UserGroupInformation.java:1657
> org.apache.tez.runtime.task.TaskRunner2Callable.callInternal()
> TaskRunner2Callable.java:61
> org.apache.tez.runtime.task.TaskRunner2Callable.callInternal()
> TaskRunner2Callable.java:37
> org.apache.tez.common.CallableWithNdc.call() CallableWithNdc.java:36
> java.util.concurrent.FutureTask.run() FutureTask.java:266
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor$Worker)
> ThreadPoolExecutor.java:1142
> java.util.concurrent.ThreadPoolExecutor$Worker.run()
> ThreadPoolExecutor.java:617
> java.lang.Thread.run() Thread.java:745
> {code}
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