rednaxelafx commented on pull request #29975: URL: https://github.com/apache/spark/pull/29975#issuecomment-705462436
https://github.com/apache/spark/pull/29975#issuecomment-705356435 > sorry for my bad memory, is it an existing issue that subexpression elimination can cause perf regression because of the eager execution? e.g. an expression is inside a condition branch (e.g. CASE WHEN) and may not be evaluated. It's possible to cause performance regression, but I don't think conditional expressions are going to be an issue. From the latest Spark master: https://github.com/apache/spark/blob/5effa8ea261ba59214afedc2853d1b248b330ca6/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/EquivalentExpressions.scala#L81-L97 You can see that CSE excludes the conditional branches from conditional expressions, so you won't have expressions accidentally hoisted from those branches. ---------------------------------------------------------------- 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] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
