dtenedor commented on code in PR #41439: URL: https://github.com/apache/spark/pull/41439#discussion_r1259029827
########## sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/AssignNewExprIds.scala: ########## @@ -0,0 +1,79 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.apache.spark.sql.catalyst.optimizer + +import scala.collection.mutable + +import org.apache.spark.sql.catalyst.expressions.{Alias, Attribute, Expression, ExprId, NamedExpression} +import org.apache.spark.sql.catalyst.expressions.aggregate.{AggregateExpression, Partial, PartialMerge} +import org.apache.spark.sql.catalyst.plans.logical.LogicalPlan +import org.apache.spark.sql.catalyst.rules.Rule + +/** + * Reassigns expression IDs in every expression of the given LogicalPlan (including subqueries + * contained in the plan). The rule applies to CTEs as well as subquery expressions. + * After the rule is done, we guarantee that all expression IDs in the plan are different from the + * original plan (except intermediate results of aggregate functions), and there is a consistent + * mapping between all the original IDs and the newly assigned IDs throughout the plan. + * Intermediate results of aggregate functions (such as PartialMerge etc) retain their IDs. + * The purpose of the rule is to support safely adding multiple copies of the same subplan, e.g. + * during subquery decorrelation. + */ +object AssignNewExprIds extends Rule[LogicalPlan] { + def apply(plan: LogicalPlan): LogicalPlan = { + val reassignedExprs = mutable.HashMap.empty[ExprId, Attribute] + plan.transformUpWithSubqueries { + case q => q.transformExpressionsUp({ + case e: Expression => assignNewExprIdsinExpr(e, reassignedExprs) + }) + } + } + + private def assignNewExprIdsinExpr(input: Expression, + reassignedExprs: mutable.HashMap[ExprId, Attribute]): Expression = + input match { + case a: Attribute => + reassignedExprs.get(a.exprId).getOrElse { + val newAttribute = a.withExprId(NamedExpression.newExprId) + reassignedExprs.put(a.exprId, newAttribute) + reassignedExprs.put(newAttribute.exprId, newAttribute) + newAttribute + } + case a: Alias => + val newAlias = Alias(a.child, a.name)(NamedExpression.newExprId, + a.qualifier, a.explicitMetadata, a.nonInheritableMetadataKeys) + reassignedExprs.put(a.exprId, newAlias.toAttribute) + reassignedExprs.put(newAlias.exprId, newAlias.toAttribute) + newAlias + case a: AggregateExpression => + if (a.mode == PartialMerge || a.mode == Partial) { Review Comment: As discussed offline, let's leave this part out for now, it is OK if we don't update these internal attribute reference IDs for now, in the interest of fixing this correctness bug in a simple way. -- 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]
