spark CollectMetricsExec 源码

spark CollectMetricsExec 代码

文件路径：/sql/core/src/main/scala/org/apache/spark/sql/execution/CollectMetricsExec.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.execution

import org.apache.spark.TaskContext
import org.apache.spark.rdd.RDD
import org.apache.spark.sql.Row
import org.apache.spark.sql.catalyst.{CatalystTypeConverters, InternalRow}
import org.apache.spark.sql.catalyst.expressions.{Attribute, NamedExpression, SortOrder}
import org.apache.spark.sql.catalyst.plans.physical.Partitioning
import org.apache.spark.sql.execution.adaptive.AdaptiveSparkPlanHelper
import org.apache.spark.sql.execution.columnar.InMemoryTableScanExec
import org.apache.spark.sql.types.StructType

/**
 * Collect arbitrary (named) metrics from a [[SparkPlan]].
 */
case class CollectMetricsExec(
    name: String,
    metricExpressions: Seq[NamedExpression],
    child: SparkPlan)
  extends UnaryExecNode {

  private lazy val accumulator: AggregatingAccumulator = {
    val acc = AggregatingAccumulator(metricExpressions, child.output)
    acc.register(sparkContext, Option("Collected metrics"))
    acc
  }

  val metricsSchema: StructType = {
    StructType.fromAttributes(metricExpressions.map(_.toAttribute))
  }

  // This is not used very frequently (once a query); it is not useful to use code generation here.
  private lazy val toRowConverter: InternalRow => Row = {
    CatalystTypeConverters.createToScalaConverter(metricsSchema)
      .asInstanceOf[InternalRow => Row]
  }

  def collectedMetrics: Row = toRowConverter(accumulator.value)

  override def output: Seq[Attribute] = child.output

  override def outputPartitioning: Partitioning = child.outputPartitioning

  override def outputOrdering: Seq[SortOrder] = child.outputOrdering

  override protected def doExecute(): RDD[InternalRow] = {
    val collector = accumulator
    collector.reset()
    child.execute().mapPartitions { rows =>
      // Only publish the value of the accumulator when the task has completed. This is done by
      // updating a task local accumulator ('updater') which will be merged with the actual
      // accumulator as soon as the task completes. This avoids the following problems during the
      // heartbeat:
      // - Correctness issues due to partially completed/visible updates.
      // - Performance issues due to excessive serialization.
      val updater = collector.copyAndReset()
      TaskContext.get().addTaskCompletionListener[Unit] { _ =>
        if (collector.isZero) {
          collector.setState(updater)
        } else {
          collector.merge(updater)
        }
      }

      rows.map { r =>
        updater.add(r)
        r
      }
    }
  }

  override protected def withNewChildInternal(newChild: SparkPlan): CollectMetricsExec =
    copy(child = newChild)
}

object CollectMetricsExec extends AdaptiveSparkPlanHelper {
  /**
   * Recursively collect all collected metrics from a query tree.
   */
  def collect(plan: SparkPlan): Map[String, Row] = {
    val metrics = collectWithSubqueries(plan) {
      case collector: CollectMetricsExec =>
        Map(collector.name -> collector.collectedMetrics)
      case tableScan: InMemoryTableScanExec =>
        CollectMetricsExec.collect(tableScan.relation.cachedPlan)
    }
    metrics.reduceOption(_ ++ _).getOrElse(Map.empty)
  }
}

相关信息

spark 源码目录

相关文章

spark AggregatingAccumulator 源码

spark AliasAwareOutputExpression 源码

spark BaseScriptTransformationExec 源码

spark CacheManager 源码

spark CoGroupedIterator 源码

spark Columnar 源码

spark CommandResultExec 源码

spark DataSourceScanExec 源码

spark ExistingRDD 源码

spark ExpandExec 源码