org.apache.pig.data

Class InternalSortedBag

java.lang.Object

org.apache.pig.data.DefaultAbstractBag

org.apache.pig.data.SelfSpillBag

org.apache.pig.data.SortedSpillBag

org.apache.pig.data.InternalSortedBag

All Implemented Interfaces:

Serializable, Comparable, Iterable<Tuple>, org.apache.hadoop.io.Writable, org.apache.hadoop.io.WritableComparable, DataBag, Spillable

public class InternalSortedBag
extends SortedSpillBag

An ordered collection of Tuples (possibly) with multiples. Data is stored unsorted as it comes in, and only sorted when it is time to dump it to a file or when the first iterator is requested. Experementation found this to be the faster than storing it sorted to begin with. We allow a user defined comparator, but provide a default comparator in cases where the user doesn't specify one. This bag is not registered with SpillableMemoryManager. It calculates the number of tuples to hold in memory and spill pro-actively into files.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.pig.data.SelfSpillBag

SelfSpillBag.MemoryLimits

Nested classes/interfaces inherited from class org.apache.pig.data.DefaultAbstractBag

DefaultAbstractBag.BagDelimiterTuple, DefaultAbstractBag.EndBag, DefaultAbstractBag.StartBag

Field Summary

Fields inherited from class org.apache.pig.data.SelfSpillBag

memLimit

Fields inherited from class org.apache.pig.data.DefaultAbstractBag

endBag, MAX_SPILL_FILES, mContents, mSize, mSpillFiles, startBag

Constructor Summary

Constructors

Constructor and Description
InternalSortedBag()
InternalSortedBag(Comparator<Tuple> comp)
InternalSortedBag(int bagCount, Comparator<Tuple> comp)
InternalSortedBag(int bagCount, float percent, Comparator<Tuple> comp)

Method Summary

Methods

Modifier and Type	Method and Description
void	add(Tuple t) Add a tuple to the bag.
boolean	isDistinct() Find out if the bag is distinct.
boolean	isSorted() Find out if the bag is sorted.
Iterator<Tuple>	iterator() Get an iterator to the bag.
long	proactive_spill(Comparator<Tuple> comp) Sort contents of mContents and write them to disk
long	spill() Instructs an object to spill whatever it can to disk and release references to any data structures it spills.

Methods inherited from class org.apache.pig.data.DefaultAbstractBag

addAll, addAll, addAll, clear, compareTo, equals, getMemorySize, getSpillFile, hashCode, incSpillCount, incSpillCount, markSpillableIfNecessary, markStale, readFields, reportProgress, sampleContents, size, toString, warn, write

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

InternalSortedBag

public InternalSortedBag()

InternalSortedBag

public InternalSortedBag(Comparator<Tuple> comp)

InternalSortedBag

public InternalSortedBag(int bagCount,
                 Comparator<Tuple> comp)

InternalSortedBag

public InternalSortedBag(int bagCount,
                 float percent,
                 Comparator<Tuple> comp)

Method Detail

add

public void add(Tuple t)

Description copied from class: DefaultAbstractBag

Add a tuple to the bag.

Specified by:

add in interface DataBag

Overrides:

add in class DefaultAbstractBag

Parameters:

t - tuple to add.

isSorted

public boolean isSorted()

Description copied from interface: DataBag

Find out if the bag is sorted.

Returns:

true if this is a sorted data bag, false otherwise.

isDistinct

public boolean isDistinct()

Description copied from interface: DataBag

Find out if the bag is distinct.

Returns:

true if the bag is a distinct bag, false otherwise.

iterator

public Iterator<Tuple> iterator()

Description copied from interface: DataBag

Get an iterator to the bag. For default and distinct bags, no particular order is guaranteed. For sorted bags the order is guaranteed to be sorted according to the provided comparator.

Returns:

tuple iterator

spill

public long spill()

Description copied from interface: Spillable

Instructs an object to spill whatever it can to disk and release references to any data structures it spills.

Returns:

number of objects spilled.

proactive_spill

public long proactive_spill(Comparator<Tuple> comp)

Description copied from class: SortedSpillBag

Sort contents of mContents and write them to disk

Overrides:

proactive_spill in class SortedSpillBag

Parameters:

comp - Comparator to sort contents of mContents

Returns:

number of tuples spilled