[GitHub] [spark] cloud-fan commented on a change in pull request #24706: [SPARK-23128][SQL] A new approach to do adaptive execution in Spark SQL

[GitBox <gi...@apache.org>]

cloud-fan commented on a change in pull request #24706: [SPARK-23128][SQL] A new approach to do adaptive execution in Spark SQL
URL: https://github.com/apache/spark/pull/24706#discussion_r288638558
 
 

 ##########
 File path: sql/core/src/main/scala/org/apache/spark/sql/execution/adaptive/InsertAdaptiveSparkPlan.scala
 ##########
 @@ -0,0 +1,130 @@
+/*
+ * 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 scala.collection.concurrent.TrieMap
+import scala.collection.mutable
+
+import org.apache.spark.sql.{execution, SparkSession}
+import org.apache.spark.sql.catalyst.expressions
+import org.apache.spark.sql.catalyst.plans.logical.LogicalPlan
+import org.apache.spark.sql.catalyst.rules.Rule
+import org.apache.spark.sql.execution._
+import org.apache.spark.sql.execution.command.ExecutedCommandExec
+import org.apache.spark.sql.execution.exchange.Exchange
+import org.apache.spark.sql.internal.SQLConf
+import org.apache.spark.sql.types.StructType
+
+/**
+ * This rule wraps the query plan with an [[AdaptiveSparkPlanExec]], which executes the query plan
+ * and re-optimize the plan during execution based on runtime data statistics.
+ *
+ * Note that this rule is stateful and thus should not be reused across query executions.
+ */
+case class InsertAdaptiveSparkPlan(session: SparkSession) extends Rule[SparkPlan] {
+
+  private val conf = session.sessionState.conf
+
+  // Exchange-reuse is shared across the entire query, including sub-queries.
+  private val stageCache = new TrieMap[StructType, mutable.Buffer[(Exchange, QueryStageExec)]]()
+
+  override def apply(plan: SparkPlan): SparkPlan = plan match {
+    case _: ExecutedCommandExec => plan
+    case _ if conf.runtimeReoptimizationEnabled && supportAdaptive(plan) =>
+      try {
+        // Plan sub-queries recursively and pass in the shared stage cache for exchange reuse. Fall
+        // back to non-adaptive mode if adaptive execution is supported in any of the sub-queries.
+        val subqueryMap = buildSubqueryMap(plan)
+        // Run preparation rules.
+        val preparations = AdaptiveSparkPlanExec.createQueryStagePreparationRules(
+          session.sessionState.conf, subqueryMap)
+        val newPlan = AdaptiveSparkPlanExec.applyPhysicalRules(plan, preparations)
+        logDebug(s"Adaptive execution enabled for plan: $plan")
+        AdaptiveSparkPlanExec(newPlan, session.cloneSession(), subqueryMap, stageCache)
 
 Review comment:
   why do we need a cloned session here?

----------------------------------------------------------------
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:
users@infra.apache.org


With regards,
Apache Git Services

---------------------------------------------------------------------
To unsubscribe, e-mail: reviews-unsubscribe@spark.apache.org
For additional commands, e-mail: reviews-help@spark.apache.org