dilipbiswal commented on a change in pull request #24759: [SPARK-27395][SQL] Improve EXPLAIN command URL: https://github.com/apache/spark/pull/24759#discussion_r316447655
########## File path: sql/core/src/main/scala/org/apache/spark/sql/execution/ExplainUtils.scala ########## @@ -0,0 +1,237 @@ +/* + * 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 + +import scala.collection.mutable +import scala.collection.mutable.ArrayBuffer + +import org.apache.spark.sql.AnalysisException +import org.apache.spark.sql.catalyst.expressions.{Expression, PlanExpression} +import org.apache.spark.sql.catalyst.plans.QueryPlan +import org.apache.spark.sql.catalyst.trees.TreeNodeTag + +object ExplainUtils { + /** + * Given a input physical plan, performs the following tasks. + * 1. Computes the operator id for current operator and records it in the operaror + * by setting a tag. + * 2. Computes the whole stage codegen id for current operator and records it in the + * operator by setting a tag. + * 3. Generate the two part explain output for this plan. + * 1. First part explains the operator tree with each operator tagged with an unique + * identifier. + * 2. Second part explans each operator in a verbose manner. + * + * Note : This function skips over subqueries. They are handled by its caller. + * + * @param plan Input query plan to process + * @param append function used to append the explain output + * @startOperationID The start value of operation id. The subsequent operations will + * be assigned higher value. + * + * @return The last generated operation id for this input plan. This is to ensure we + * always assign incrementing unique id to each operator. + * + */ + private def processPlanSkippingSubqueries[T <: QueryPlan[T]]( + plan: => QueryPlan[T], + append: String => Unit, + startOperatorID: Int): Int = { + + // ReusedSubqueryExecs are skipped over + if (plan.isInstanceOf[BaseSubqueryExec]) { + return startOperatorID + } + + val operationIDs = new mutable.ArrayBuffer[(Int, QueryPlan[_])]() + var currentOperatorID = startOperatorID + try { + currentOperatorID = generateOperatorIDs(plan, currentOperatorID, operationIDs) + generateWholeStageCodegenIds(plan) + + QueryPlan.append( + plan, + append, + verbose = false, + addSuffix = false, + printOperatorId = true) + + append("\n") + var i: Integer = 0 + for ((opId, curPlan) <- operationIDs) { + append(curPlan.verboseStringWithOperatorId()) + } + } catch { + case e: AnalysisException => append(e.toString) + } + currentOperatorID + } + + /** + * Given a input physical plan, performs the following tasks. + * 1. Generates the explain output for the input plan excluding the subquery plans. + * 2. Generates the explain output for each subquery referenced in the plan. + */ + def processPlan[T <: QueryPlan[T]]( + plan: => QueryPlan[T], + append: String => Unit): Unit = { + try { + val subqueries = ArrayBuffer.empty[(SparkPlan, Expression, SparkPlan)] + var currentOperatorID = 0 + currentOperatorID = processPlanSkippingSubqueries(plan, append, currentOperatorID) + getSubqueries(plan, subqueries) + var i = 0 + + // Process all the subqueries in the plan. + for (sub <- subqueries) { + if (i == 0) { + append("\n===== Subqueries =====\n\n") + } + i = i + 1 + append(s"Subquery:$i Hosting operator id = " + + s"${getOpId(sub._1)} Hosting Expression = ${sub._2}\n") + + // For each subquery expression in the parent plan, process its child plan to compute + // the explain output. + currentOperatorID = processPlanSkippingSubqueries( + sub._3, + append, + currentOperatorID) + append("\n") + } + } finally { + removeTags(plan) + } + } + + /** + * Traverses the supplied input plan in a bottem-up fashion does the following : + * 1. produces a map : operator identifier -> operator + * 2. Records the operator id via setting a tag in the operator. + * Note : + * 1. Operator such as WholeStageCodegenExec and InputAdapter are skipped as they don't + * appear in the explain output. + * 2. operator identifier starts at startOperatorID + 1 + * @param plan Input query plan to process + * @startOperationID The start value of operation id. The subsequent operations will + * be assigned higher value. + * @operatorIDs A output parameter that contains a map of operator id and query plan. This + * is used by caller to print the detail portion of the plan. + * @return The last generated operation id for this input plan. This is to ensure we + * always assign incrementing unique id to each operator. + */ + private def generateOperatorIDs( + plan: QueryPlan[_], + startOperatorID: Int, + operatorIDs: mutable.ArrayBuffer[(Int, QueryPlan[_])]): Int = { + var currentOperationID = startOperatorID + // Skip the subqueries as they are not printed as part of main query block. + if (plan.isInstanceOf[BaseSubqueryExec]) { + return currentOperationID + } + plan.foreachUp { + case p: WholeStageCodegenExec => + case p: InputAdapter => + case other: QueryPlan[_] => + if (!other.getTagValue(QueryPlan.OP_ID_TAG).isDefined) { + currentOperationID += 1 + other.setTagValue(QueryPlan.OP_ID_TAG, currentOperationID) + operatorIDs += ((currentOperationID, other)) + } + other.innerChildren.foreach { plan => + currentOperationID = generateOperatorIDs(plan, + currentOperationID, + operatorIDs) + } + } + currentOperationID + } + + /** + * Traverses the supplied input plan in a top-down fashion and records the + * whole stage code gen id in the plan via setting a tag. + */ + private def generateWholeStageCodegenIds(plan: QueryPlan[_]): Unit = { + // Skip the subqueries as they are not printed as part of main query block. + if (plan.isInstanceOf[BaseSubqueryExec]) { + return + } + var currentCodegenId = -1 + plan.foreach { + case p: WholeStageCodegenExec => currentCodegenId = p.codegenStageId + case p: InputAdapter => currentCodegenId = -1 + case other: QueryPlan[_] => + if (currentCodegenId != -1) { + other.setTagValue(QueryPlan.CODEGEN_ID_TAG, currentCodegenId) + } + other.innerChildren.foreach { plan => Review comment: @cloud-fan same comment as above. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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