spark DescribeTableExec 源码

spark DescribeTableExec 代码

文件路径：/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/v2/DescribeTableExec.scala

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 * 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
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package org.apache.spark.sql.execution.datasources.v2

import scala.collection.JavaConverters._
import scala.collection.mutable.ArrayBuffer

import org.apache.spark.sql.catalyst.InternalRow
import org.apache.spark.sql.catalyst.catalog.CatalogTableType
import org.apache.spark.sql.catalyst.expressions.Attribute
import org.apache.spark.sql.catalyst.util.quoteIfNeeded
import org.apache.spark.sql.connector.catalog.{CatalogV2Util, SupportsMetadataColumns, Table, TableCatalog}
import org.apache.spark.sql.connector.expressions.IdentityTransform

case class DescribeTableExec(
    output: Seq[Attribute],
    table: Table,
    isExtended: Boolean) extends LeafV2CommandExec {
  override protected def run(): Seq[InternalRow] = {
    val rows = new ArrayBuffer[InternalRow]()
    addSchema(rows)
    addPartitioning(rows)

    if (isExtended) {
      addMetadataColumns(rows)
      addTableDetails(rows)
    }
    rows.toSeq
  }

  private def addTableDetails(rows: ArrayBuffer[InternalRow]): Unit = {
    rows += emptyRow()
    rows += toCatalystRow("# Detailed Table Information", "", "")
    rows += toCatalystRow("Name", table.name(), "")

    val tableType = if (table.properties().containsKey(TableCatalog.PROP_EXTERNAL)) {
      CatalogTableType.EXTERNAL.name
    } else {
      CatalogTableType.MANAGED.name
    }
    rows += toCatalystRow("Type", tableType, "")
    CatalogV2Util.TABLE_RESERVED_PROPERTIES
      .filterNot(_ == TableCatalog.PROP_EXTERNAL)
      .foreach(propKey => {
        if (table.properties.containsKey(propKey)) {
          rows += toCatalystRow(propKey.capitalize, table.properties.get(propKey), "")
        }
      })
    val properties =
      conf.redactOptions(table.properties.asScala.toMap).toList
        .filter(kv => !CatalogV2Util.TABLE_RESERVED_PROPERTIES.contains(kv._1))
        .sortBy(_._1).map {
        case (key, value) => key + "=" + value
      }.mkString("[", ",", "]")
    rows += toCatalystRow("Table Properties", properties, "")
  }

  private def addSchema(rows: ArrayBuffer[InternalRow]): Unit = {
    rows ++= table.schema.map{ column =>
      toCatalystRow(
        column.name, column.dataType.simpleString, column.getComment().orNull)
    }
  }

  private def addMetadataColumns(rows: ArrayBuffer[InternalRow]): Unit = table match {
    case hasMeta: SupportsMetadataColumns if hasMeta.metadataColumns.nonEmpty =>
      rows += emptyRow()
      rows += toCatalystRow("# Metadata Columns", "", "")
      rows ++= hasMeta.metadataColumns.map { column =>
        toCatalystRow(
          column.name,
          column.dataType.simpleString,
          Option(column.comment()).getOrElse(""))
      }
    case _ =>
  }

  private def addPartitioning(rows: ArrayBuffer[InternalRow]): Unit = {
    if (table.partitioning.nonEmpty) {
      val partitionColumnsOnly = table.partitioning.forall(t => t.isInstanceOf[IdentityTransform])
      if (partitionColumnsOnly) {
        rows += toCatalystRow("# Partition Information", "", "")
        rows += toCatalystRow(s"# ${output(0).name}", output(1).name, output(2).name)
        rows ++= table.partitioning
          .map(_.asInstanceOf[IdentityTransform].ref.fieldNames())
          .map { fieldNames =>
            val nestedField = table.schema.findNestedField(fieldNames)
            assert(nestedField.isDefined,
              s"Not found the partition column ${fieldNames.map(quoteIfNeeded).mkString(".")} " +
              s"in the table schema ${table.schema().catalogString}.")
            nestedField.get
          }.map { case (path, field) =>
            toCatalystRow(
              (path :+ field.name).map(quoteIfNeeded(_)).mkString("."),
              field.dataType.simpleString,
              field.getComment().orNull)
          }
      } else {
        rows += emptyRow()
        rows += toCatalystRow("# Partitioning", "", "")
        rows ++= table.partitioning.zipWithIndex.map {
          case (transform, index) => toCatalystRow(s"Part $index", transform.describe(), "")
        }
      }
    }
  }

  private def emptyRow(): InternalRow = toCatalystRow("", "", "")
}

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