maropu commented on a change in pull request #20303: [SPARK-23128][SQL] A new approach to do adaptive execution in Spark SQL URL: https://github.com/apache/spark/pull/20303#discussion_r251715099
########## File path: sql/core/src/main/scala/org/apache/spark/sql/execution/adaptive/PlanQueryStage.scala ########## @@ -0,0 +1,57 @@ +/* + * 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.SparkSession +import org.apache.spark.sql.catalyst.rules.Rule +import org.apache.spark.sql.execution.SparkPlan +import org.apache.spark.sql.execution.exchange.{BroadcastExchangeExec, Exchange, ReusedExchangeExec, ShuffleExchangeExec} + +/** + * Divide the spark plan into multiple QueryStages. For each Exchange in the plan, it wraps it with + * a [[QueryStage]]. At the end it adds an [[AdaptiveSparkPlan]] at the top, which will drive the + * execution of query stages. + */ +case class PlanQueryStage(session: SparkSession) extends Rule[SparkPlan] { + + def apply(plan: SparkPlan): SparkPlan = { + var id = 0 + val exchangeToQueryStage = new java.util.IdentityHashMap[Exchange, QueryStage] + val planWithStages = plan.transformUp { + case e: ShuffleExchangeExec => + val queryStage = ShuffleQueryStage(id, e) + id += 1 + exchangeToQueryStage.put(e, queryStage) + queryStage + case e: BroadcastExchangeExec => + val queryStage = BroadcastQueryStage(id, e) + id += 1 + exchangeToQueryStage.put(e, queryStage) + queryStage + // The `ReusedExchangeExec` was added in the rule `ReuseExchange`, via transforming up the + // query plan. This rule also transform up the query plan, so when we hit `ReusedExchangeExec` + // here, the exchange being reused must already be hit before and there should be an entry + // for it in `exchangeToQueryStage`. + case e: ReusedExchangeExec => + val existingQueryStage = exchangeToQueryStage.get(e.child) + assert(existingQueryStage != null, "The exchange being reused should be hit before.") + ReusedQueryStage(existingQueryStage, e.output) Review comment: We need this wrapper? Can we just return `existingQueryStage`? ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
