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https://issues.apache.org/jira/browse/SPARK-4782?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14567254#comment-14567254
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Luca Rosellini commented on SPARK-4782:
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Hi Jianshi,
I've just hit the same problem as you, it seems quite inefficient to have to
serialize to JSON when you already have a {{Map\[String,Any\]}}.
I've opened a PR in github that adds this feature in a generic way, check it
out at: [https://github.com/apache/spark/pull/6554].
Hopefully it will be merged in master.
The patch extends {{inferSchema}} functionality to any RDD of type T for which
you can provide a function mapping from {{RDD\[T\]}} to
{{RDD\[Map\[String,Any\]\]}}.
In your case, you already have an {{RDD\[Map\[String,Any\]\]}}, so you can
simply pass the identity function, something like this:
{{JsonRDD.inferSchema(json, 1.0, conf.columnNameOfCorruptRecord, \{
(a:RDD\[Map\[String,Any\]\],b:String) => a \}))}}
> Add inferSchema support for RDD[Map[String, Any]]
> -------------------------------------------------
>
> Key: SPARK-4782
> URL: https://issues.apache.org/jira/browse/SPARK-4782
> Project: Spark
> Issue Type: Improvement
> Components: SQL
> Reporter: Jianshi Huang
> Priority: Minor
>
> The best way to convert RDD[Map[String, Any]] to SchemaRDD currently seems to
> be converting each Map to JSON String first and use JsonRDD.inferSchema on it.
> It's very inefficient.
> Instead of JsonRDD, RDD[Map[String, Any]] is a better common denominator for
> Schemaless data as adding Map like interface to any serialization format is
> easy.
> So please add inferSchema support to RDD[Map[String, Any]]. *Then for any new
> serialization format we want to support, we just need to add a Map interface
> wrapper to it*
> Jianshi
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