cloud-fan commented on a change in pull request #32602: URL: https://github.com/apache/spark/pull/32602#discussion_r636083336
########## File path: sql/core/src/main/scala/org/apache/spark/sql/execution/adaptive/ConvertToLocalRelation.scala ########## @@ -0,0 +1,32 @@ +/* + * 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.plans.logical.{LocalRelation, LogicalPlan} +import org.apache.spark.sql.catalyst.rules.Rule + +/** + * Converts empty query stage to empty `LocalRelation` + */ +object ConvertToLocalRelation extends Rule[LogicalPlan] { + override def apply(plan: LogicalPlan): LogicalPlan = plan transform { + case l @ LogicalQueryStage(_, stage: QueryStageExec) if stage.resultOption.get().isDefined && Review comment: Sorry I made the wrong decision. This may change the output partitioning and is not always safe/beneficial (we may add extra shuffles in the planning phase later). Looking at the optimizations for empty local relations, some of them are likely beneficial and we can always do: eliminate join, aggregate, limit, repartition, sort, generate Some may not that beneficial and we shouldn't do: simplify union, eliminate project/filter/sample. My new idea: 1. Create a new rule `PropagateEmptyRelationBasic`, which deals with local relaion only, and is not very beneficial (eliminate project, filter, etc), and runs in the normal optimizer only 2. Create a new rule `PropagateEmptyRelationAdvanced`, which deals with both local relation and query stage, and is very beneficial (eliminate join, aggregate, etc.), and runs in both normal and AQE optimizer The old `EliminateUnnecessaryJoin` and `PropagateEmptyRelation` rules should be removed and merged into the new rules. `PropagateEmptyRelationAdvanced` may not be able to access QueryStageExec which is in sql/core. We can let this rule take `checkRowCount` functiton as a parameter. -- 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]
