[GitHub] [spark] cloud-fan commented on a change in pull request #33671: [SPARK-36447][SQL] Avoid inlining non-deterministic With-CTEs

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cloud-fan commented on a change in pull request #33671:
URL: https://github.com/apache/spark/pull/33671#discussion_r687020021



##########
File path: sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/ResolveWithCTE.scala
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@@ -0,0 +1,65 @@
+/*
+ * 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.catalyst.analysis
+
+import scala.collection.mutable
+
+import org.apache.spark.sql.catalyst.expressions.SubqueryExpression
+import org.apache.spark.sql.catalyst.plans.logical.{CTERelationDef, CTERelationRef, LogicalPlan, WithCTE}
+import org.apache.spark.sql.catalyst.rules.Rule
+import org.apache.spark.sql.catalyst.trees.TreePattern.{CTE, PLAN_EXPRESSION}
+
+/**
+ * Updates CTE references with the resolve output attributes of corresponding CTE definitions.
+ */
+object ResolveWithCTE extends Rule[LogicalPlan] {
+  override def apply(plan: LogicalPlan): LogicalPlan = {
+    if (plan.containsAllPatterns(CTE)) {
+      val cteDefMap = mutable.HashMap.empty[Long, CTERelationDef]
+      resolveWithCTE(plan, cteDefMap)
+    } else {
+      plan
+    }
+  }
+
+  private def resolveWithCTE(
+      plan: LogicalPlan,
+      cteDefMap: mutable.HashMap[Long, CTERelationDef]): LogicalPlan = {
+    plan.resolveOperatorsDownWithPruning(_.containsAllPatterns(CTE)) {
+      case w @ WithCTE(_, cteDefs) =>
+        cteDefs.foreach { cteDef =>
+          if (cteDef.resolved) {
+            cteDefMap.put(cteDef.id, cteDef)
+          }
+        }
+        w
+
+      case ref: CTERelationRef if !ref.resolved =>
+        cteDefMap.get(ref.cteId).map { cteDef =>
+          CTERelationRef(cteDef.id, cteDef.resolved, cteDef.output)
+        }.getOrElse {
+          ref
+        }
+
+      case other =>
+        other.transformExpressionsWithPruning(_.containsAllPatterns(PLAN_EXPRESSION, CTE)) {
+          case e: SubqueryExpression => e.withNewPlan(resolveWithCTE(e.plan, cteDefMap))

Review comment:
       If the main query has more than one subqueries, when resolving the second subquery, the `cteDefMap` will contain CTE defs from the first subquery. I think we should clone the map here?




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