Package org.apache.cassandra.io.sstable

Class IndexSummary

java.lang.Object

org.apache.cassandra.utils.concurrent.SharedCloseableImpl

org.apache.cassandra.utils.concurrent.WrappedSharedCloseable

org.apache.cassandra.io.sstable.IndexSummary

All Implemented Interfaces:

java.lang.AutoCloseable, SharedCloseable

public class IndexSummary
extends WrappedSharedCloseable

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	IndexSummary.IndexSummarySerializer

Field Summary

Fields

Modifier and Type	Field	Description
static IndexSummary.IndexSummarySerializer	serializer

Constructor Summary

Constructors

Constructor	Description
IndexSummary(IPartitioner partitioner, Memory offsets, int offsetCount, Memory entries, long entriesLength, int sizeAtFullSampling, int minIndexInterval, int samplingLevel)

Method Summary

Modifier and Type	Method	Description
void	addTo(Ref.IdentityCollection identities)
int	binarySearch(PartitionPosition key)
double	getEffectiveIndexInterval()
int	getEffectiveIndexIntervalAfterIndex(int index)	Returns the number of primary (on-disk) index entries between the index summary entry at `index` and the next index summary entry (assuming there is one).
long	getEndInSummary(int index)
long	getEstimatedKeyCount()	Returns an estimate of the total number of keys in the SSTable.
byte[]	getKey(int index)
int	getMaxNumberOfEntries()	Returns the number of entries this summary would have if it were at the full sampling level, which is equal to the number of entries in the primary on-disk index divided by the min index interval.
int	getMinIndexInterval()
long	getOffHeapSize()
long	getPosition(int index)
int	getPositionInSummary(int index)	Gets the position of the actual index summary entry in our Memory attribute, 'bytes'.
int	getSamplingLevel()
IndexSummary	sharedCopy()
int	size()

Methods inherited from class org.apache.cassandra.utils.concurrent.SharedCloseableImpl

close, close, isCleanedUp

Methods inherited from class java.lang.Object

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

Field Detail

serializer

public static final IndexSummary.IndexSummarySerializer serializer

Constructor Detail

IndexSummary

public IndexSummary(IPartitioner partitioner,
                    Memory offsets,
                    int offsetCount,
                    Memory entries,
                    long entriesLength,
                    int sizeAtFullSampling,
                    int minIndexInterval,
                    int samplingLevel)

Method Detail

binarySearch

public int binarySearch(PartitionPosition key)

getPositionInSummary

public int getPositionInSummary(int index)

Gets the position of the actual index summary entry in our Memory attribute, 'bytes'.

Parameters:

index - The index of the entry or key to get the position for

Returns:

an offset into our Memory attribute where the actual entry resides

getKey

public byte[] getKey(int index)

addTo

public void addTo(Ref.IdentityCollection identities)

Specified by:

addTo in interface SharedCloseable

Overrides:

addTo in class SharedCloseableImpl

getPosition

public long getPosition(int index)

getEndInSummary

public long getEndInSummary(int index)

getMinIndexInterval

public int getMinIndexInterval()

getEffectiveIndexInterval

public double getEffectiveIndexInterval()

getEstimatedKeyCount

public long getEstimatedKeyCount()

Returns an estimate of the total number of keys in the SSTable.

size

public int size()

getSamplingLevel

public int getSamplingLevel()

getMaxNumberOfEntries

public int getMaxNumberOfEntries()

Returns the number of entries this summary would have if it were at the full sampling level, which is equal to the number of entries in the primary on-disk index divided by the min index interval.

getOffHeapSize

public long getOffHeapSize()

getEffectiveIndexIntervalAfterIndex

public int getEffectiveIndexIntervalAfterIndex(int index)

Returns the number of primary (on-disk) index entries between the index summary entry at `index` and the next index summary entry (assuming there is one). Without any downsampling, this will always be equivalent to the index interval.

Parameters:

index - the index of an index summary entry (between zero and the index entry size)

Returns:

the number of partitions after `index` until the next partition with a summary entry

sharedCopy

public IndexSummary sharedCopy()

Returns:

a new instance of the object representing the same state and backed by the same underlying resources. Coordinates with the original (and other instances) when the underlying resource should be closed. Throws an exception if the shared resource has already been closed.