HyukjinKwon commented on a change in pull request #21586:
URL: https://github.com/apache/spark/pull/21586#discussion_r806382550



##########
File path: docs/sql-migration-guide-upgrade.md
##########
@@ -138,6 +138,8 @@ license: |
     need to specify a value with units like "30s" now, to avoid being 
interpreted as milliseconds; otherwise, 
     the extremely short interval that results will likely cause applications 
to fail.
 
+  - When turning a Dataset to another Dataset, Spark will up cast the fields 
in the original Dataset to the type of corresponding fields in the target 
DataSet. In version 2.4 and earlier, this up cast is not very strict, e.g. 
`Seq("str").toDS.as[Int]` fails, but `Seq("str").toDS.as[Boolean]` works and 
throw NPE during execution. In Spark 3.0, the up cast is stricter and turning 
String into something else is not allowed, i.e. `Seq("str").toDS.as[Boolean]` 
will fail during analysis.

Review comment:
       Yeah we should




-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: [email protected]

For queries about this service, please contact Infrastructure at:
[email protected]



---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]

Reply via email to