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https://issues.apache.org/jira/browse/HIVE-18301?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16304383#comment-16304383
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Rui Li commented on HIVE-18301:
-------------------------------
My understanding is if the HadoopRDD is cached, the records are not produced by
record reader and IOContext is not populated. Therefore the information in
IOContext will be unavailable, e.g. the input path. This may cause problem
because some operators need to take certain actions when input file changes --
{{Operator::cleanUpInputFileChanged}}.
So basically my point is we have to figure out the scenarios where IOContext is
necessary. Then decide whether we should disable caching in such cases.
> Investigate to enable MapInput cache in Hive on Spark
> -----------------------------------------------------
>
> Key: HIVE-18301
> URL: https://issues.apache.org/jira/browse/HIVE-18301
> Project: Hive
> Issue Type: Bug
> Reporter: liyunzhang
> Assignee: liyunzhang
>
> Before IOContext problem is found in MapTran when spark rdd cache is enabled
> in HIVE-8920.
> so we disabled rdd cache in MapTran at
> [SparkPlanGenerator|https://github.com/kellyzly/hive/blob/master/ql/src/java/org/apache/hadoop/hive/ql/exec/spark/SparkPlanGenerator.java#L202].
> The problem is IOContext seems not initialized correctly in the spark yarn
> client/cluster mode and caused the exception like
> {code}
> Job aborted due to stage failure: Task 93 in stage 0.0 failed 4 times, most
> recent failure: Lost task 93.3 in stage 0.0 (TID 616, bdpe48):
> java.lang.RuntimeException: Error processing row:
> java.lang.NullPointerException
> at
> org.apache.hadoop.hive.ql.exec.spark.SparkMapRecordHandler.processRow(SparkMapRecordHandler.java:165)
> at
> org.apache.hadoop.hive.ql.exec.spark.HiveMapFunctionResultList.processNextRecord(HiveMapFunctionResultList.java:48)
> at
> org.apache.hadoop.hive.ql.exec.spark.HiveMapFunctionResultList.processNextRecord(HiveMapFunctionResultList.java:27)
> at
> org.apache.hadoop.hive.ql.exec.spark.HiveBaseFunctionResultList.hasNext(HiveBaseFunctionResultList.java:85)
> at
> scala.collection.convert.Wrappers$JIteratorWrapper.hasNext(Wrappers.scala:42)
> at
> org.apache.spark.shuffle.sort.BypassMergeSortShuffleWriter.write(BypassMergeSortShuffleWriter.java:125)
> at
> org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:79)
> at
> org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:47)
> at org.apache.spark.scheduler.Task.run(Task.scala:85)
> at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:274)
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
> at java.lang.Thread.run(Thread.java:745)
> Caused by: java.lang.NullPointerException
> at
> org.apache.hadoop.hive.ql.exec.AbstractMapOperator.getNominalPath(AbstractMapOperator.java:101)
> at
> org.apache.hadoop.hive.ql.exec.MapOperator.cleanUpInputFileChangedOp(MapOperator.java:516)
> at
> org.apache.hadoop.hive.ql.exec.Operator.cleanUpInputFileChanged(Operator.java:1187)
> at
> org.apache.hadoop.hive.ql.exec.MapOperator.process(MapOperator.java:546)
> at
> org.apache.hadoop.hive.ql.exec.spark.SparkMapRecordHandler.processRow(SparkMapRecordHandler.java:152)
> ... 12 more
> Driver stacktrace:
> {code}
> in yarn client/cluster mode, sometimes
> [ExecMapperContext#currentInputPath|https://github.com/kellyzly/hive/blob/master/ql/src/java/org/apache/hadoop/hive/ql/exec/mr/ExecMapperContext.java#L109]
> is null when rdd cach is enabled.
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