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https://issues.apache.org/jira/browse/SPARK-3528?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15779436#comment-15779436
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Umesh Chaudhary commented on SPARK-3528:
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[~gip] looks like when we provide file:/// as URI, executors should be able to
find it from their respective host, so makes sense for NODE_LOCAL. Found
this[1] user list discussion worth mentioning. IMHO, executors read the data
into same JVM (from the mentioned URI) and after that data becomes
PROCESS_LOCAL for the executors.
[1]
http://apache-spark-user-list.1001560.n3.nabble.com/When-does-Spark-switch-from-PROCESS-LOCAL-to-NODE-LOCAL-or-RACK-LOCAL-td7091.html
> Reading data from file:/// should be called NODE_LOCAL not PROCESS_LOCAL
> ------------------------------------------------------------------------
>
> Key: SPARK-3528
> URL: https://issues.apache.org/jira/browse/SPARK-3528
> Project: Spark
> Issue Type: Bug
> Components: Spark Core
> Affects Versions: 1.1.0
> Reporter: Andrew Ash
> Priority: Critical
>
> Note that reading from {{file:///.../pom.xml}} is called a PROCESS_LOCAL task
> {noformat}
> spark> sc.textFile("pom.xml").count
> ...
> 14/09/15 00:59:13 INFO TaskSetManager: Starting task 0.0 in stage 0.0 (TID 0,
> localhost, PROCESS_LOCAL, 1191 bytes)
> 14/09/15 00:59:13 INFO TaskSetManager: Starting task 1.0 in stage 0.0 (TID 1,
> localhost, PROCESS_LOCAL, 1191 bytes)
> 14/09/15 00:59:13 INFO Executor: Running task 0.0 in stage 0.0 (TID 0)
> 14/09/15 00:59:13 INFO Executor: Running task 1.0 in stage 0.0 (TID 1)
> 14/09/15 00:59:13 INFO HadoopRDD: Input split:
> file:/Users/aash/git/spark/pom.xml:20862+20863
> 14/09/15 00:59:13 INFO HadoopRDD: Input split:
> file:/Users/aash/git/spark/pom.xml:0+20862
> {noformat}
> There is an outstanding TODO in {{HadoopRDD.scala}} that may be related:
> {noformat}
> override def getPreferredLocations(split: Partition): Seq[String] = {
> // TODO: Filtering out "localhost" in case of file:// URLs
> val hadoopSplit = split.asInstanceOf[HadoopPartition]
> hadoopSplit.inputSplit.value.getLocations.filter(_ != "localhost")
> }
> {noformat}
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