peter-toth commented on code in PR #42223: URL: https://github.com/apache/spark/pull/42223#discussion_r1284125676
########## sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/CombineJoinedAggregates.scala: ########## @@ -0,0 +1,132 @@ +/* + * 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.ArrayBuffer + +import org.apache.spark.sql.catalyst.expressions.{Alias, And, Attribute, AttributeMap, Expression, NamedExpression, Or} +import org.apache.spark.sql.catalyst.expressions.aggregate.AggregateExpression +import org.apache.spark.sql.catalyst.plans.{Cross, FullOuter, Inner, JoinType, LeftOuter, RightOuter} +import org.apache.spark.sql.catalyst.plans.logical.{Aggregate, Filter, Join, LeafNode, LogicalPlan, Project, SerializeFromObject} +import org.apache.spark.sql.catalyst.rules.Rule +import org.apache.spark.sql.catalyst.trees.TreePattern.{AGGREGATE, JOIN} + +/** + * This rule eliminates the [[Join]] if all the join side are [[Aggregate]]s by combine these + * [[Aggregate]]s. This rule also support the nested [[Join]], as long as all the join sides for + * every [[Join]] are [[Aggregate]]s. + * + * Note: this rule doesn't following cases: + * 1. One of the to be merged two [[Aggregate]]s with child [[Filter]] and the other one is not. Review Comment: If a conditions is `f(c)` and `c` is not used in the aggregate function (e.g. it is `sum(a)`) then the project also removes `c` besides adding a new boolean column (we can write `sum(a) FILTER (WHERE <boolean column>)` instead of `sum(a) FILTER (WHERE f(c))`) . If `f(c1, c2, ..., c10)` is the condition and none of these are in the aggregate function then the project removes 10 columns and adds only 1 boolean. What you are reffering to is the worst case, but IMO on average, the extra projects helps. -- 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: reviews-unsubscr...@spark.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org