com.mapr.db.mapreduce

Class TablePartitioner

java.lang.Object

org.apache.hadoop.mapreduce.Partitioner<ByteBufWritableComparable,org.ojai.Document>

com.mapr.db.mapreduce.TablePartitioner

All Implemented Interfaces:

org.apache.hadoop.conf.Configurable

public class TablePartitioner
extends org.apache.hadoop.mapreduce.Partitioner<ByteBufWritableComparable,org.ojai.Document>
implements org.apache.hadoop.conf.Configurable

TablePartitioner controls the partitioning of key space of a JSON table for intermediate map-out functions. The key/id is used to derive the partition.

Constructor Summary

Constructors

Constructor and Description
TablePartitioner()

Method Summary

Modifier and Type	Method and Description
org.apache.hadoop.conf.Configuration	getConf() Returns the current configuration.
int	getPartition(ByteBufWritableComparable key, org.ojai.Document value, int numPartitions) Gets the partition number for a given key (hence record) given the total number of partitions i.e.
void	setConf(org.apache.hadoop.conf.Configuration configuration) Sets the configuration.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

TablePartitioner

public TablePartitioner()

Method Detail

getPartition

public int getPartition(ByteBufWritableComparable key,
                        org.ojai.Document value,
                        int numPartitions)

Gets the partition number for a given key (hence record) given the total number of partitions i.e. number of reduce-tasks for the job.

Typically a hash function on a all or a subset of the key.

Specified by:

getPartition in class org.apache.hadoop.mapreduce.Partitioner<ByteBufWritableComparable,org.ojai.Document>

Parameters:

key - The key to be partitioned.

value - The entry value.

numPartitions - The total number of partitions.

Returns:

The partition number for the key.

See Also:

Partitioner.getPartition( java.lang.Object, java.lang.Object, int)

getConf

public org.apache.hadoop.conf.Configuration getConf()

Returns the current configuration.

Specified by:

getConf in interface org.apache.hadoop.conf.Configurable

Returns:

The current configuration.

See Also:

Configurable.getConf()

setConf

public void setConf(org.apache.hadoop.conf.Configuration configuration)

Sets the configuration. This is used to determine the start keys for the given table.

Specified by:

setConf in interface org.apache.hadoop.conf.Configurable

Parameters:

configuration - The configuration to set.

See Also:

Configurable.setConf( org.apache.hadoop.conf.Configuration)