ulysses-you commented on a change in pull request #32602: URL: https://github.com/apache/spark/pull/32602#discussion_r636165023
########## 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: I see the issue. If we worry about the `LocalRelation` output partitioning, we can just mark `LocalRelationExec` output partitioning as `SinglePartition` to avoid extra shuffle. But it doesn't work with optimization like non empty left semi/anti elimintaion and multi-join case. > we can always do: eliminate join, aggregate Not sure we can always do this if we don't want to introduce extra shuffle. And the issue it has already existed in current `EliminateUnnecessaryJoin`, like this plan ``` Aggregate (same key with join) Join Inner LocalRelation xxx ``` An another idea, if we plan to support extra shuffle later and don't expect introduce shuffle at AQE optimzier side, then is it better to check the physical plan `requiredChildDistribution` ? We can only allow one node which has a valid `requiredChildDistribution` (not `UnspecifiedDistribution`) in one query stage, and skip optimize if one query stage has two or more valid `requiredChildDistribution` nodes. Thus we can run `PropagateEmptyRelation` safely. -- 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]
