org.elasticsearch.search.aggregations.metrics.cardinality

クラス HyperLogLogPlusPlus

java.lang.Object

org.elasticsearch.search.aggregations.metrics.cardinality.HyperLogLogPlusPlus

すべての実装されたインタフェース:

AutoCloseable, Releasable

public final class HyperLogLogPlusPlus
extends Object
implements Releasable

Hyperloglog++ counter, implemented based on pseudo code from http://static.googleusercontent.com/media/research.google.com/fr//pubs/archive/40671.pdf and its appendix https://docs.google.com/document/d/1gyjfMHy43U9OWBXxfaeG-3MjGzejW1dlpyMwEYAAWEI/view?fullscreen This implementation is different from the original implementation in that it uses a hash table instead of a sorted list for linear counting. Although this requires more space and makes hyperloglog (which is less accurate) used sooner, this is also considerably faster. Trying to understand what this class does whithout having read the paper is considered adventurous.

フィールドのサマリー

フィールド

修飾子とタイプ	フィールドと説明
static int	DEFAULT_PRECISION
static int	MAX_PRECISION
static int	MIN_PRECISION

コンストラクタのサマリー

コンストラクタ

コンストラクタと説明
HyperLogLogPlusPlus(int precision, BigArrays bigArrays, long initialBucketCount)

メソッドのサマリー

修飾子とタイプ	メソッドと説明
long	cardinality(long bucket)
void	close()
void	collect(long bucket, long hash)
long	maxBucket()
static long	memoryUsage(int precision) Return the expected per-bucket memory usage for the given precision.
void	merge(long thisBucket, HyperLogLogPlusPlus other, long otherBucket)
int	precision()
static int	precisionFromThreshold(long count) Compute the required precision so that count distinct entries would be counted with linear counting.
static HyperLogLogPlusPlus	readFrom(StreamInput in, BigArrays bigArrays)
void	writeTo(long bucket, StreamOutput out)

クラスから継承されたメソッド java.lang.Object

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

フィールドの詳細

MIN_PRECISION

public static final int MIN_PRECISION

関連項目:

定数フィールド値

DEFAULT_PRECISION

public static final int DEFAULT_PRECISION

関連項目:

定数フィールド値

MAX_PRECISION

public static final int MAX_PRECISION

関連項目:

定数フィールド値

コンストラクタの詳細

HyperLogLogPlusPlus

public HyperLogLogPlusPlus(int precision,
                           BigArrays bigArrays,
                           long initialBucketCount)

メソッドの詳細

precisionFromThreshold

public static int precisionFromThreshold(long count)

Compute the required precision so that count distinct entries would be counted with linear counting.

memoryUsage

public static long memoryUsage(int precision)

Return the expected per-bucket memory usage for the given precision.

precision

public int precision()

maxBucket

public long maxBucket()

merge

public void merge(long thisBucket,
                  HyperLogLogPlusPlus other,
                  long otherBucket)

collect

public void collect(long bucket,
                    long hash)

cardinality

public long cardinality(long bucket)

close

public void close()

定義:

close インタフェース内 AutoCloseable

定義:

close インタフェース内 Releasable

writeTo

public void writeTo(long bucket,
                    StreamOutput out)
             throws IOException

例外:

IOException

readFrom

public static HyperLogLogPlusPlus readFrom(StreamInput in,
                                           BigArrays bigArrays)
                                    throws IOException

例外:

IOException