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https://issues.apache.org/jira/browse/PIG-4580?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14567562#comment-14567562
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Rohini Palaniswamy commented on PIG-4580:
-----------------------------------------
So with this patch only in case of skewed outer join, the sample is also
broadcast to the skewed join vertex. After 0.15, we need to revisit the fix for
PIG-4377 to see if we can do it in a better way so that we still do dynamic
parallelism for skewed outer join as well.
+1.
> Fix TestTezAutoParallelism.testSkewedJoinIncreaseParallelism test failure
> -------------------------------------------------------------------------
>
> Key: PIG-4580
> URL: https://issues.apache.org/jira/browse/PIG-4580
> Project: Pig
> Issue Type: Bug
> Components: tez
> Reporter: Daniel Dai
> Assignee: Daniel Dai
> Fix For: 0.15.0
>
> Attachments: PIG-4580-1.patch
>
>
> If a vertex need to increase parallelism dynamically, it cannot has
> additional broadcast input. In the test case, join vertex requires a
> broadcast edge to acquire sample file (used in IsFirstReduceOfKeyTez), and
> the join vertex use PartitionerDefinedVertexManager which can increase
> parallelism dynamically. If that happens, we will see exception:
> {code}
> Fetch failed:java.lang.IndexOutOfBoundsException
> at java.nio.Buffer.checkIndex(Buffer.java:532)
> at
> java.nio.ByteBufferAsLongBufferB.get(ByteBufferAsLongBufferB.java:115)
> at
> org.apache.tez.runtime.library.common.sort.impl.TezSpillRecord.getIndex(TezSpillRecord.java:101)
> at
> org.apache.tez.runtime.library.common.shuffle.Fetcher.getTezIndexRecord(Fetcher.java:596)
> at
> org.apache.tez.runtime.library.common.shuffle.Fetcher.doLocalDiskFetch(Fetcher.java:537)
> at
> org.apache.tez.runtime.library.common.shuffle.Fetcher.setupLocalDiskFetch(Fetcher.java:518)
> at
> org.apache.tez.runtime.library.common.shuffle.Fetcher.callInternal(Fetcher.java:191)
> at
> org.apache.tez.runtime.library.common.shuffle.Fetcher.callInternal(Fetcher.java:70)
> at org.apache.tez.common.CallableWithNdc.call(CallableWithNdc.java:36)
> 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)
> {code}
> The fix disable dynamic parallelism if there is a broadcast edge (including
> sample file in skewed outer join, scalar followed by skewed join/order by).
> Also in inner skewed join, the sample file is not needed in join vertex, so
> it is not necessarily to broadcast it thus disable dynamic parallelism.
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