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java.lang.Object org.apache.hadoop.mapreduce.Partitioner<K,V> org.apache.hadoop.mapreduce.lib.partition.TotalOrderPartitioner<K,V>
@InterfaceAudience.Public @InterfaceStability.Stable public class TotalOrderPartitioner<K extends WritableComparable<?>,V>
Partitioner effecting a total order by reading split points from an externally generated source.
Field Summary | |
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static String |
DEFAULT_PATH
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static String |
MAX_TRIE_DEPTH
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static String |
NATURAL_ORDER
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static String |
PARTITIONER_PATH
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Constructor Summary | |
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TotalOrderPartitioner()
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Method Summary | |
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Configuration |
getConf()
Return the configuration used by this object. |
int |
getPartition(K key,
V value,
int numPartitions)
Get the partition number for a given key (hence record) given the total number of partitions i.e. |
static String |
getPartitionFile(Configuration conf)
Get the path to the SequenceFile storing the sorted partition keyset. |
void |
setConf(Configuration conf)
Read in the partition file and build indexing data structures. |
static void |
setPartitionFile(Configuration conf,
Path p)
Set the path to the SequenceFile storing the sorted partition keyset. |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Field Detail |
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public static final String DEFAULT_PATH
public static final String PARTITIONER_PATH
public static final String MAX_TRIE_DEPTH
public static final String NATURAL_ORDER
Constructor Detail |
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public TotalOrderPartitioner()
Method Detail |
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public void setConf(Configuration conf)
BinaryComparable
and
total.order.partitioner.natural.order is not false, a trie
of the first total.order.partitioner.max.trie.depth(2) + 1 bytes
will be built. Otherwise, keys will be located using a binary search of
the partition keyset using the RawComparator
defined for this job. The input file must be sorted with the same
comparator and contain JobContextImpl.getNumReduceTasks()
- 1 keys.
setConf
in interface Configurable
public Configuration getConf()
Configurable
getConf
in interface Configurable
public int getPartition(K key, V value, int numPartitions)
Partitioner
Typically a hash function on a all or a subset of the key.
getPartition
in class Partitioner<K extends WritableComparable<?>,V>
key
- the key to be partioned.value
- the entry value.numPartitions
- the total number of partitions.
key
.public static void setPartitionFile(Configuration conf, Path p)
public static String getPartitionFile(Configuration conf)
setPartitionFile(Configuration, Path)
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