c21 commented on a change in pull request #31873: URL: https://github.com/apache/spark/pull/31873#discussion_r597327356
########## File path: sql/core/src/main/scala/org/apache/spark/sql/execution/adaptive/EliminateUnnecessaryJoin.scala ########## @@ -0,0 +1,91 @@ +/* + * 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.execution.adaptive + +import org.apache.spark.sql.catalyst.planning.ExtractSingleColumnNullAwareAntiJoin +import org.apache.spark.sql.catalyst.plans.{Inner, LeftAnti, LeftSemi} +import org.apache.spark.sql.catalyst.plans.logical.{Join, LocalRelation, LogicalPlan} +import org.apache.spark.sql.catalyst.rules.Rule +import org.apache.spark.sql.execution.joins.HashedRelationWithAllNullKeys + +/** + * This optimization rule detects and eliminates unnecessary Join: + * 1. Join is single column NULL-aware anti join (NAAJ), and broadcasted [[HashedRelation]] + * is [[HashedRelationWithAllNullKeys]]. Eliminate join to an empty [[LocalRelation]]. + * + * 2. Join is inner join, and either side of join is empty. Eliminate join to an empty + * [[LocalRelation]]. + * + * 3. Join is left semi join + * 3.1. Join right side is empty. Eliminate join to an empty [[LocalRelation]]. + * 3.2. Join right side is non-empty and condition is empty. Eliminate join to its left side. + * + * 4. Join is left anti join + * 4.1. Join right side is empty. Eliminate join to its left side. + * 4.2. Join right side is non-empty and condition is empty. Eliminate join to an empty + * [[LocalRelation]]. + * + * This applies to all joins (sort merge join, shuffled hash join, broadcast hash join, and + * broadcast nested loop join), because sort merge join and shuffled hash join will be changed + * to broadcast hash join with AQE at the first place. + */ +object EliminateUnnecessaryJoin extends Rule[LogicalPlan] { + + private def isRelationWithAllNullKeys(plan: LogicalPlan) = plan match { + case LogicalQueryStage(_, stage: BroadcastQueryStageExec) + if stage.resultOption.get().isDefined => + stage.broadcast.relationFuture.get().value == HashedRelationWithAllNullKeys + case _ => false + } + + private def checkRowCount(plan: LogicalPlan, hasRow: Boolean): Boolean = plan match { Review comment: @maropu - sorry I don't quite get here, `checkRowCount(j.right, hasRow = false` still exists in your example. Am I missing anything? Thanks. -- 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]
