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HadoopTableReader

:hive-version: 2.3.6 :hadoop-version: 2.10.0 :url-hive-javadoc: https://hive.apache.org/javadocs/r{hive-version}/api :url-hadoop-javadoc: https://hadoop.apache.org/docs/r{hadoop-version}/api

HadoopTableReader is a TableReader.md[TableReader] to create an HadoopRDD for scanning <> or <> tables stored in Hadoop.

HadoopTableReader is used by HiveTableScanExec.md[HiveTableScanExec] physical operator when requested to HiveTableScanExec.md#doExecute[execute].

=== [[creating-instance]] Creating HadoopTableReader Instance

HadoopTableReader takes the following to be created:

  • [[attributes]] Attributes
  • [[partitionKeys]] Partition Keys (Seq[Attribute])
  • [[tableDesc]] Hive {url-hive-javadoc}/org/apache/hive/hcatalog/templeton/TableDesc.html[TableDesc]
  • [[sparkSession]] SparkSession.md[SparkSession]
  • [[hadoopConf]] Hadoop {url-hadoop-javadoc}/org/apache/hadoop/conf/Configuration.html[Configuration]

HadoopTableReader initializes the <>.

=== [[makeRDDForTable]] makeRDDForTable Method

[source, scala]

makeRDDForTable( hiveTable: HiveTable): RDD[InternalRow]


NOTE: makeRDDForTable is part of the TableReader.md#makeRDDForTable[TableReader] contract to...FIXME.

makeRDDForTable simply calls the private <> with...FIXME

==== [[makeRDDForTable-private]] makeRDDForTable Method

[source, scala]

makeRDDForTable( hiveTable: HiveTable, deserializerClass: Class[_ <: Deserializer], filterOpt: Option[PathFilter]): RDD[InternalRow]


makeRDDForTable...FIXME

NOTE: makeRDDForTable is used when...FIXME

=== [[makeRDDForPartitionedTable]] makeRDDForPartitionedTable Method

[source, scala]

makeRDDForPartitionedTable( partitions: Seq[HivePartition]): RDD[InternalRow]


NOTE: makeRDDForPartitionedTable is part of the TableReader.md#makeRDDForPartitionedTable[TableReader] contract to...FIXME.

makeRDDForPartitionedTable simply calls the private <> with...FIXME

==== [[makeRDDForPartitionedTable-private]] makeRDDForPartitionedTable Method

[source, scala]

makeRDDForPartitionedTable( partitionToDeserializer: Map[HivePartition, Class[_ <: Deserializer]], filterOpt: Option[PathFilter]): RDD[InternalRow]


makeRDDForPartitionedTable...FIXME

NOTE: makeRDDForPartitionedTable is used when...FIXME

=== [[createHadoopRdd]] Creating HadoopRDD -- createHadoopRdd Internal Method

[source, scala]

createHadoopRdd( tableDesc: TableDesc, path: String, inputFormatClass: Class[InputFormat[Writable, Writable]]): RDD[Writable]


createHadoopRdd <> for the input path and tableDesc.

createHadoopRdd creates an HadoopRDD (with the <<broadcastedHadoopConf, broadcast Hadoop Configuration>>, the input inputFormatClass, and the <<_minSplitsPerRDD, minimum number of partitions>>) and takes (_maps over) the values.

NOTE: createHadoopRdd adds a HadoopRDD and a MapPartitionsRDD to a RDD lineage.

NOTE: createHadoopRdd is used when HadoopTableReader is requested to <> and <>.

=== [[initializeLocalJobConfFunc]] initializeLocalJobConfFunc Utility

[source, scala]

initializeLocalJobConfFunc( path: String, tableDesc: TableDesc)( jobConf: JobConf): Unit


initializeLocalJobConfFunc...FIXME

NOTE: initializeLocalJobConfFunc is used when HadoopTableReader is requested to <>.

=== [[internal-properties]] Internal Properties

[cols="30m,70",options="header",width="100%"] |=== | Name | Description

| _broadcastedHadoopConf a| [[_broadcastedHadoopConf]] Hadoop {url-hadoop-javadoc}/org/apache/hadoop/conf/Configuration.html[Configuration] broadcast to executors

| _minSplitsPerRDD a| [[_minSplitsPerRDD]] Minimum number of partitions for a <>:

  • 0 for local mode
  • The greatest of Hadoop's mapreduce.job.maps (default: 1) and Spark Core's default minimum number of partitions for Hadoop RDDs (not higher than 2)

|===


Last update: 2020-07-29