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java.lang.Objectorg.apache.hadoop.mapred.lib.TotalOrderPartitioner<K,V>
public class TotalOrderPartitioner<K extends WritableComparable,V>
Partitioner effecting a total order by reading split points from an externally generated source.
| Field Summary | |
|---|---|
static String |
DEFAULT_PATH
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| Constructor Summary | |
|---|---|
TotalOrderPartitioner()
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| Method Summary | |
|---|---|
void |
configure(JobConf job)
Read in the partition file and build indexing data structures. |
int |
getPartition(K key,
V value,
int numPartitions)
Get the paritition number for a given key (hence record) given the total number of partitions i.e. |
static String |
getPartitionFile(JobConf job)
Get the path to the SequenceFile storing the sorted partition keyset. |
static void |
setPartitionFile(JobConf job,
Path p)
Set the path to the SequenceFile storing the sorted partition keyset. |
| Methods inherited from class java.lang.Object |
|---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| Field Detail |
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public static final String DEFAULT_PATH
| Constructor Detail |
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public TotalOrderPartitioner()
| Method Detail |
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public void configure(JobConf job)
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 JobConf.getNumReduceTasks() - 1 keys.
configure in interface JobConfigurablejob - the configuration
public int getPartition(K key,
V value,
int numPartitions)
PartitionerTypically a hash function on a all or a subset of the key.
getPartition in interface Partitioner<K extends WritableComparable,V>key - the key to be paritioned.value - the entry value.numPartitions - the total number of partitions.
key.
public static void setPartitionFile(JobConf job,
Path p)
public static String getPartitionFile(JobConf job)
setPartitionFile(JobConf,Path)
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