peter-toth commented on a change in pull request #28885:
URL: https://github.com/apache/spark/pull/28885#discussion_r446632088



##########
File path: 
sql/core/src/main/scala/org/apache/spark/sql/execution/reuse/Reuse.scala
##########
@@ -0,0 +1,95 @@
+/*
+ * 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.reuse
+
+import scala.collection.mutable.Map
+
+import org.apache.spark.sql.catalyst.rules.Rule
+import org.apache.spark.sql.execution.{BaseSubqueryExec, 
ExecSubqueryExpression, ReusedSubqueryExec, SparkPlan}
+import org.apache.spark.sql.execution.exchange.{Exchange, ReusedExchangeExec}
+import org.apache.spark.sql.internal.SQLConf
+import org.apache.spark.sql.types.StructType
+
+/**
+ * Find out duplicated exchanges and subqueries in the whole spark plan 
including subqueries, then
+ * use the same exhange or subquery for all the references.
+ */
+case class WholePlanReuse(conf: SQLConf) extends Rule[SparkPlan] {
+
+  def apply(plan: SparkPlan): SparkPlan = {
+    if (conf.exchangeReuseEnabled || conf.subqueryReuseEnabled) {

Review comment:
       Hmm, I'm not sure why would anyone disable reuse subquery or reuse 
exchange at all. But those flags do exist and we shouldn't change their meaning 
that exchange or subquery reuse shouldn't happen when they are disabled.
   IMHO if we introduce this "whole plan reuse" with this new rule, then we 
should still respect the old flags.
   I also think this new rule can replace the old rules entirely with one whole 
plan traversal and I don't see any reason why would we keep the old rules. 
Actually, wouldn't be confusing if we had reuse related code at many places?




----------------------------------------------------------------
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]

Reply via email to