yaooqinn commented on PR #45588: URL: https://github.com/apache/spark/pull/45588#issuecomment-2008579737
Hi @yaooqinn The regression you mentioned was performed in SPARK-43049 and undone in SPARK-46478. SPARK-43049 modified the `string->varchar(255)` to `string->clob` in the Oracle write path to accommodate sufficient character-length. Regrettably, the modification has caused a decline in performance. In this PR, the changes happen in the read path. The table schema change at the spark side can happen when users perform CTAS against MySQL, i.e. `CREATE TABLE abc AS SELECT * FROM a_jdbc_table`. The table `abc` will result in a schema change after this PR. It's important to keep in mind that the results of arithmetic operations can differ based on the type of data that is returned. Since SPARK-45561 already had such impacts for TINYINT in Spark 3.5.1, it seems okay to extend to other types. -- 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]
