Spark 之 HiveStrategies

HiveTableRelation 相关代码

HiveStrategies.scala
当 relation.tableMeta.stats.isEmpty 是， 即调用 hiveTableWithStats

class DetermineTableStats(session: SparkSession) extends Rule[LogicalPlan] {
  private def hiveTableWithStats(relation: HiveTableRelation): HiveTableRelation = {
    val table = relation.tableMeta
    val partitionCols = relation.partitionCols
    // For partitioned tables, the partition directory may be outside of the table directory.
    // Which is expensive to get table size. Please see how we implemented it in the AnalyzeTable.
    val sizeInBytes = if (conf.fallBackToHdfsForStatsEnabled && partitionCols.isEmpty) {
      try {
        val hadoopConf = session.sessionState.newHadoopConf()
        val tablePath = new Path(table.location)
        val fs: FileSystem = tablePath.getFileSystem(hadoopConf)
        fs.getContentSummary(tablePath).getLength
      } catch {
        case e: IOException =>
          logWarning("Failed to get table size from HDFS.", e)
          conf.defaultSizeInBytes
      }
    } else {
      conf.defaultSizeInBytes
    }

    val stats = Some(Statistics(sizeInBytes = BigInt(sizeInBytes)))
    relation.copy(tableStats = stats)
  }

  override def apply(plan: LogicalPlan): LogicalPlan = plan resolveOperators {
    case relation: HiveTableRelation
      if DDLUtils.isHiveTable(relation.tableMeta) && relation.tableMeta.stats.isEmpty =>
      hiveTableWithStats(relation)

    // handles InsertIntoStatement specially as the table in InsertIntoStatement is not added in its
    // children, hence not matched directly by previous HiveTableRelation case.
    case i @ InsertIntoStatement(relation: HiveTableRelation, _, _, _, _, _)
      if DDLUtils.isHiveTable(relation.tableMeta) && relation.tableMeta.stats.isEmpty =>
      i.copy(table = hiveTableWithStats(relation))
  }
}

• HiveTableRelation

/**
 * A `LogicalPlan` that represents a hive table.
 *
 * TODO: remove this after we completely make hive as a data source.
 */
case class HiveTableRelation(
    tableMeta: CatalogTable,
    dataCols: Seq[AttributeReference],
    partitionCols: Seq[AttributeReference],
    tableStats: Option[Statistics] = None,
    @transient prunedPartitions: Option[Seq[CatalogTablePartition]] = None)