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Posted to common-issues@hadoop.apache.org by "Tom White (JIRA)" <ji...@apache.org> on 2010/04/28 05:22:31 UTC
[jira] Commented: (HADOOP-6729) serializer.JavaSerialization should
be added to io.serializations by default
[ https://issues.apache.org/jira/browse/HADOOP-6729?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12861657#action_12861657 ]
Tom White commented on HADOOP-6729:
-----------------------------------
The JavaSerialization was written as an experimental serialization, to prove the abstraction. I'm not sure it should be enabled by default since it's not efficient, hasn't been tested at scale (as far as I know), and we should encourage users to use other serializations like Writables or Avro.
In any case, we could improve the error message if the type is Serializable, or print a warning.
> serializer.JavaSerialization should be added to io.serializations by default
> ----------------------------------------------------------------------------
>
> Key: HADOOP-6729
> URL: https://issues.apache.org/jira/browse/HADOOP-6729
> Project: Hadoop Common
> Issue Type: Improvement
> Components: conf
> Affects Versions: 0.20.2
> Reporter: Ted Yu
>
> org.apache.hadoop.io.serializer.JavaSerialization isn't included in io.serializations by default.
> When a class which implements the Serializable interface is used, user would see the following without serializer.JavaSerialization:
> java.lang.NullPointerException
> at
> org.apache.hadoop.io.serializer.SerializationFactory.getSerializer(SerializationFactory.java:73)
> at
> org.apache.hadoop.mapred.MapTask$MapOutputBuffer.<init>(MapTask.java:759)
> at
> org.apache.hadoop.mapred.MapTask$NewOutputCollector.<init>(MapTask.java:487)
> at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:575)
> at org.apache.hadoop.mapred.MapTask.run(MapTask.java:305)
> at org.apache.hadoop.mapred.Child.main(Child.java:170)
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