yhuai commented on a change in pull request #27670: [MINOR][DOC] Add two migration tips for Hive URL: https://github.com/apache/spark/pull/27670#discussion_r382696919
########## File path: docs/sql-migration-guide.md ########## @@ -335,6 +335,10 @@ license: | - Since Spark 3.0, we upgraded the built-in Hive from 1.2 to 2.3. You need to migrate your custom SerDes to Hive 2.3 or build your own Spark with `hive-1.2` profile. See HIVE-15167 for more details. + - Since Spark 3.0, we upgraded the built-in Hive from 1.2 to 2.3. The result decimal represent in string can be different between Hive 1.2 and Hive 2.3 when use `TRANSFORM` syntax in sql. In Hive 1.2, decimal will eliminate all non-significant zeros in precision when represents in string. But in Hive 2.3, it will always show 18 digits in precision and make up with zero if its precision is less than 18. Review comment: Let's call it out transform is used for script transformation, which depends on hive's behavior. I was not clear how a hive change can affect spark. But they realized that transform is script transformation. ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
