spark EliminateResolvedHint 源码

spark EliminateResolvedHint 代码

文件路径：/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/EliminateResolvedHint.scala

/*
 * 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.optimizer

import org.apache.spark.sql.catalyst.plans.logical._
import org.apache.spark.sql.catalyst.rules.Rule

/**
 * Replaces [[ResolvedHint]] operators from the plan. Move the [[HintInfo]] to associated [[Join]]
 * operators, otherwise remove it if no [[Join]] operator is matched.
 */
object EliminateResolvedHint extends Rule[LogicalPlan] {

  private val hintErrorHandler = conf.hintErrorHandler

  // This is also called in the beginning of the optimization phase, and as a result
  // is using transformUp rather than resolveOperators.
  def apply(plan: LogicalPlan): LogicalPlan = {
    val pulledUp = plan transformUp {
      case j: Join if j.hint == JoinHint.NONE =>
        val (newLeft, leftHints) = extractHintsFromPlan(j.left)
        val (newRight, rightHints) = extractHintsFromPlan(j.right)
        val newJoinHint = JoinHint(mergeHints(leftHints), mergeHints(rightHints))
        j.copy(left = newLeft, right = newRight, hint = newJoinHint)
    }
    pulledUp.transformUp {
      case h: ResolvedHint =>
        hintErrorHandler.joinNotFoundForJoinHint(h.hints)
        h.child
    }
  }

  /**
   * Combine a list of [[HintInfo]]s into one [[HintInfo]].
   */
  private def mergeHints(hints: Seq[HintInfo]): Option[HintInfo] = {
    hints.reduceOption((h1, h2) => h1.merge(h2, hintErrorHandler))
  }

  /**
   * Extract all hints from the plan, returning a list of extracted hints and the transformed plan
   * with [[ResolvedHint]] nodes removed. The returned hint list comes in top-down order.
   * Note that hints can only be extracted from under certain nodes. Those that cannot be extracted
   * in this method will be cleaned up later by this rule, and may emit warnings depending on the
   * configurations.
   */
  private[sql] def extractHintsFromPlan(plan: LogicalPlan): (LogicalPlan, Seq[HintInfo]) = {
    plan match {
      case h: ResolvedHint =>
        val (plan, hints) = extractHintsFromPlan(h.child)
        (plan, h.hints +: hints)
      case u: UnaryNode =>
        val (plan, hints) = extractHintsFromPlan(u.child)
        (u.withNewChildren(Seq(plan)), hints)
      // TODO revisit this logic:
      // except and intersect are semi/anti-joins which won't return more data then
      // their left argument, so the broadcast hint should be propagated here
      case i: Intersect =>
        val (plan, hints) = extractHintsFromPlan(i.left)
        (i.copy(left = plan), hints)
      case e: Except =>
        val (plan, hints) = extractHintsFromPlan(e.left)
        (e.copy(left = plan), hints)
      case p: LogicalPlan => (p, Seq.empty)
    }
  }
}

相关信息

spark 源码目录

相关文章

spark ComplexTypes 源码

spark CostBasedJoinReorder 源码

spark DecorrelateInnerQuery 源码

spark InjectRuntimeFilter 源码

spark InlineCTE 源码

spark LimitPushDownThroughWindow 源码

spark MergeScalarSubqueries 源码

spark NestedColumnAliasing 源码

spark NormalizeFloatingNumbers 源码

spark OptimizeCsvJsonExprs 源码