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https://issues.apache.org/jira/browse/SPARK-3533?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14265122#comment-14265122
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Ilya Ganelin commented on SPARK-3533:
-------------------------------------
Hi all - I have that solution (using MultipleTextOutputFormat) implemented but
sadly it doesn't work out of the box.
saveAsHadoopFileByKey should generate a text file per key *** FAILED ***
java.lang.RuntimeException: java.lang.NoSuchMethodException:
org.apache.spark.rdd.PairRDDFunctions$RDDMultipleTextOutputFormat.<init>()
at
org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:115)
Adding an init method to the definition does not help either so I'm still
digging into other options. My code is here:
https://github.com/ilganeli/spark/tree/SPARK-3533
I'll keep looking for alternatives.
> Add saveAsTextFileByKey() method to RDDs
> ----------------------------------------
>
> Key: SPARK-3533
> URL: https://issues.apache.org/jira/browse/SPARK-3533
> Project: Spark
> Issue Type: Improvement
> Components: PySpark, Spark Core
> Affects Versions: 1.1.0
> Reporter: Nicholas Chammas
>
> Users often have a single RDD of key-value pairs that they want to save to
> multiple locations based on the keys.
> For example, say I have an RDD like this:
> {code}
> >>> a = sc.parallelize(['Nick', 'Nancy', 'Bob', 'Ben',
> >>> 'Frankie']).keyBy(lambda x: x[0])
> >>> a.collect()
> [('N', 'Nick'), ('N', 'Nancy'), ('B', 'Bob'), ('B', 'Ben'), ('F', 'Frankie')]
> >>> a.keys().distinct().collect()
> ['B', 'F', 'N']
> {code}
> Now I want to write the RDD out to different paths depending on the keys, so
> that I have one output directory per distinct key. Each output directory
> could potentially have multiple {{part-}} files, one per RDD partition.
> So the output would look something like:
> {code}
> /path/prefix/B [/part-1, /part-2, etc]
> /path/prefix/F [/part-1, /part-2, etc]
> /path/prefix/N [/part-1, /part-2, etc]
> {code}
> Though it may be possible to do this with some combination of
> {{saveAsNewAPIHadoopFile()}}, {{saveAsHadoopFile()}}, and the
> {{MultipleTextOutputFormat}} output format class, it isn't straightforward.
> It's not clear if it's even possible at all in PySpark.
> Please add a {{saveAsTextFileByKey()}} method or something similar to RDDs
> that makes it easy to save RDDs out to multiple locations at once.
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