maropu commented on a change in pull request #25717: [WIP][SPARK-29013][SQL] Structurally equivalent subexpression elimination URL: https://github.com/apache/spark/pull/25717#discussion_r321992145
########## File path: sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/EquivalentExpressions.scala ########## @@ -65,35 +89,102 @@ class EquivalentExpressions { } /** - * Adds the expression to this data structure recursively. Stops if a matching expression - * is found. That is, if `expr` has already been added, its children are not added. + * Adds each expression to structural expression data structure, grouping them with existing + * structurally equivalent expressions. Non-recursive. + */ + def addStructExpr(ctx: CodegenContext, expr: Expression): Unit = { + if (expr.deterministic) { Review comment: We cannot always share a function for non-deterministic cases? e.g., ``` int subExpr1 = input[0] + random(); int subExpr2 = input[1] + random(); => int subExpr1 = subExpr(input[0]); int subExpr2 = subExpr(input[1]); int subExpr(int v) { return v + random(); } ``` ---------------------------------------------------------------- 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: us...@infra.apache.org With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org