org.apache.cassandra.io.sstable

Class IndexSummaryBuilder

java.lang.Object

org.apache.cassandra.io.sstable.IndexSummaryBuilder

public class IndexSummaryBuilder
extends java.lang.Object

Constructor Summary

Constructors

Constructor and Description
IndexSummaryBuilder(long expectedKeys, int minIndexInterval, int samplingLevel)

Method Summary

Methods

Modifier and Type	Method and Description
IndexSummary	build(IPartitioner partitioner)
IndexSummary	build(IPartitioner partitioner, DecoratedKey exclusiveUpperBound)
static int	calculateSamplingLevel(int currentSamplingLevel, int currentNumEntries, long targetNumEntries, int minIndexInterval, int maxIndexInterval)
static IndexSummary	downsample(IndexSummary existing, int newSamplingLevel, int minIndexInterval, IPartitioner partitioner) Downsamples an existing index summary to a new sampling level.
static int	entriesAtSamplingLevel(int samplingLevel, int maxSummarySize)
DecoratedKey	getMaxReadableKey(long position, int offset)
IndexSummaryBuilder	maybeAddEntry(DecoratedKey decoratedKey, long indexPosition)

Methods inherited from class java.lang.Object

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

Constructor Detail

IndexSummaryBuilder

public IndexSummaryBuilder(long expectedKeys,
                   int minIndexInterval,
                   int samplingLevel)

Method Detail

getMaxReadableKey

public DecoratedKey getMaxReadableKey(long position,
                             int offset)

maybeAddEntry

public IndexSummaryBuilder maybeAddEntry(DecoratedKey decoratedKey,
                                long indexPosition)

build

public IndexSummary build(IPartitioner partitioner)

build

public IndexSummary build(IPartitioner partitioner,
                 DecoratedKey exclusiveUpperBound)

entriesAtSamplingLevel

public static int entriesAtSamplingLevel(int samplingLevel,
                         int maxSummarySize)

calculateSamplingLevel

public static int calculateSamplingLevel(int currentSamplingLevel,
                         int currentNumEntries,
                         long targetNumEntries,
                         int minIndexInterval,
                         int maxIndexInterval)

downsample

public static IndexSummary downsample(IndexSummary existing,
                      int newSamplingLevel,
                      int minIndexInterval,
                      IPartitioner partitioner)

Downsamples an existing index summary to a new sampling level.

Parameters:

existing - an existing IndexSummary

newSamplingLevel - the target level for the new IndexSummary. This must be less than the current sampling level for `existing`.

partitioner - the partitioner used for the index summary

Returns:

a new IndexSummary