org.apache.cassandra.io.sstable
Class SSTableReader

java.lang.Object
  org.apache.cassandra.io.sstable.SSTable
      org.apache.cassandra.io.sstable.SSTableReader

public class SSTableReader
extends SSTable

SSTableReaders are open()ed by Table.onStart; after that they are created by SSTableWriter.renameAndOpen. Do not re-call open() on existing SSTable files; use the references kept by ColumnFamilyStore post-start instead.

Nested Class Summary

static class

SSTableReader.Operator TODO: Move someplace reusable

Field Summary

long	maxDataAge maxDataAge is a timestamp in local server time (e.g.

Fields inherited from class org.apache.cassandra.io.sstable.SSTable

COMPONENT_DATA, COMPONENT_FILTER, COMPONENT_INDEX, COMPONENT_STATS, components, compression, descriptor, first, last, maxTimestampComparator, metadata, partitioner, sstableComparator, sstableOrdering, TEMPFILE_MARKER

Method Summary

boolean	acquireReference()
static boolean	acquireReferences(java.lang.Iterable<SSTableReader> sstables)
static java.util.Collection<SSTableReader>	batchOpen(java.util.Set<java.util.Map.Entry<Descriptor,java.util.Set<Component>>> entries, java.util.Set<DecoratedKey> savedKeys, DataTracker tracker, CFMetaData metadata, IPartitioner partitioner)
void	cacheKey(DecoratedKey key, java.lang.Long info)
void	createLinks(java.lang.String snapshotDirectoryPath)
static DecoratedKey	decodeKey(IPartitioner p, Descriptor d, java.nio.ByteBuffer bytes) Conditionally use the deprecated 'IPartitioner.convertFromDiskFormat' method.
long	estimatedKeys()
long	estimatedKeysForRanges(java.util.Collection<Range> ranges)
void	forceFilterFailures() For testing purposes only.
static long	getApproximateKeyCount(java.lang.Iterable<SSTableReader> sstables)
Filter	getBloomFilter()
long	getBloomFilterFalsePositiveCount()
long	getBloomFilterTruePositiveCount()
java.lang.Long	getCachedPosition(DecoratedKey key, boolean updateStats)
SSTableScanner	getDirectScanner() Direct I/O SSTableScanner
SSTableScanner	getDirectScanner(Range range) Direct I/O SSTableScanner over a defined range of tokens.
EstimatedHistogram	getEstimatedColumnCount()
EstimatedHistogram	getEstimatedRowSize()
FileDataInput	getFileDataInput(DecoratedKey decoratedKey, int bufferSize)
InstrumentingCache<Pair<Descriptor,DecoratedKey>,java.lang.Long>	getKeyCache()
java.util.Collection<DecoratedKey>	getKeySamples()
java.lang.Iterable<DecoratedKey>	getKeySamples(Range range)
long	getMaxTimestamp()
long	getPosition(DecoratedKey decoratedKey, SSTableReader.Operator op)
java.util.List<Pair<java.lang.Long,java.lang.Long>>	getPositionsForRanges(java.util.Collection<Range> ranges) Determine the minimal set of sections that can be extracted from this SSTable to cover the given ranges.
long	getRecentBloomFilterFalsePositiveCount()
long	getRecentBloomFilterTruePositiveCount()
ReplayPosition	getReplayPosition()
SSTableScanner	getScanner(QueryFilter filter)
static void	logOpenException(Descriptor descriptor, java.io.IOException e)
void	markCompacted() Mark the sstable as compacted.
boolean	newSince(long age) Tests if the sstable contains data newer than the given age param (in localhost currentMilli time).
long	onDiskLength()
static SSTableReader	open(Descriptor desc)
static SSTableReader	open(Descriptor desc, CFMetaData metadata)
static SSTableReader	open(Descriptor descriptor, java.util.Set<Component> components, CFMetaData metadata, IPartitioner partitioner)
static SSTableReader	open(Descriptor descriptor, java.util.Set<Component> components, java.util.Set<DecoratedKey> savedKeys, DataTracker tracker, CFMetaData metadata, IPartitioner partitioner)
RandomAccessReader	openDataReader(boolean skipIOCache)
static long	readRowSize(java.io.DataInput in, Descriptor d)
void	releaseReference()
static void	releaseReferences(java.lang.Iterable<SSTableReader> sstables)
void	setTrackedBy(DataTracker tracker)
long	uncompressedLength()

Methods inherited from class org.apache.cassandra.io.sstable.SSTable

bytesOnDisk, delete, getColumnFamilyName, getFilename, getMinimalKey, getTableName, getTotalBytes, toString, tryComponentFromFilename

Methods inherited from class java.lang.Object

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

Field Detail

maxDataAge

public final long maxDataAge

maxDataAge is a timestamp in local server time (e.g. System.currentTimeMilli) which represents an uppper bound to the newest piece of data stored in the sstable. In other words, this sstable does not contain items created later than maxDataAge. The field is not serialized to disk, so relying on it for more than what truncate does is not advised. When a new sstable is flushed, maxDataAge is set to the time of creation. When a sstable is created from compaction, maxDataAge is set to max of all merged tables. The age is in milliseconds since epoc and is local to this host.

Method Detail

getApproximateKeyCount

public static long getApproximateKeyCount(java.lang.Iterable<SSTableReader> sstables)

open

public static SSTableReader open(Descriptor desc)
                          throws java.io.IOException

Throws:

java.io.IOException

open

public static SSTableReader open(Descriptor desc,
                                 CFMetaData metadata)
                          throws java.io.IOException

Throws:

java.io.IOException

open

public static SSTableReader open(Descriptor descriptor,
                                 java.util.Set<Component> components,
                                 CFMetaData metadata,
                                 IPartitioner partitioner)
                          throws java.io.IOException

Throws:

java.io.IOException

open

public static SSTableReader open(Descriptor descriptor,
                                 java.util.Set<Component> components,
                                 java.util.Set<DecoratedKey> savedKeys,
                                 DataTracker tracker,
                                 CFMetaData metadata,
                                 IPartitioner partitioner)
                          throws java.io.IOException

Throws:

java.io.IOException

logOpenException

public static void logOpenException(Descriptor descriptor,
                                    java.io.IOException e)

batchOpen

public static java.util.Collection<SSTableReader> batchOpen(java.util.Set<java.util.Map.Entry<Descriptor,java.util.Set<Component>>> entries,
                                                            java.util.Set<DecoratedKey> savedKeys,
                                                            DataTracker tracker,
                                                            CFMetaData metadata,
                                                            IPartitioner partitioner)

setTrackedBy

public void setTrackedBy(DataTracker tracker)

forceFilterFailures

public void forceFilterFailures()

For testing purposes only.

getBloomFilter

public Filter getBloomFilter()

estimatedKeys

public long estimatedKeys()

Returns:

An estimate of the number of keys in this SSTable.

estimatedKeysForRanges

public long estimatedKeysForRanges(java.util.Collection<Range> ranges)

Parameters:

ranges -

Returns:

An estimate of the number of keys for given ranges in this SSTable.

getKeySamples

public java.util.Collection<DecoratedKey> getKeySamples()

Returns:

Approximately 1/INDEX_INTERVALth of the keys in this SSTable.

getKeySamples

public java.lang.Iterable<DecoratedKey> getKeySamples(Range range)

getPositionsForRanges

public java.util.List<Pair<java.lang.Long,java.lang.Long>> getPositionsForRanges(java.util.Collection<Range> ranges)

Determine the minimal set of sections that can be extracted from this SSTable to cover the given ranges.

Returns:

A sorted list of (offset,end) pairs that cover the given ranges in the datafile for this SSTable.

cacheKey

public void cacheKey(DecoratedKey key,
                     java.lang.Long info)

getCachedPosition

public java.lang.Long getCachedPosition(DecoratedKey key,
                                        boolean updateStats)

getPosition

public long getPosition(DecoratedKey decoratedKey,
                        SSTableReader.Operator op)

Parameters:

decoratedKey - The key to apply as the rhs to the given Operator.

op - The Operator defining matching keys: the nearest key to the target matching the operator wins.

Returns:

The position in the data file to find the key, or -1 if the key is not present

uncompressedLength

public long uncompressedLength()

Returns:

The length in bytes of the data for this SSTable. For compressed files, this is not the same thing as the on disk size (see onDiskLength())

onDiskLength

public long onDiskLength()

Returns:

The length in bytes of the on disk size for this SSTable. For compressed files, this is not the same thing as the data length (see length())

acquireReference

public boolean acquireReference()

releaseReference

public void releaseReference()

markCompacted

public void markCompacted()

Mark the sstable as compacted. When calling this function, the caller must ensure that the SSTableReader is not referenced anywhere except for threads holding a reference.

getScanner

public SSTableScanner getScanner(QueryFilter filter)

Parameters:

filter - filter to use when reading the columns

Returns:

A Scanner for seeking over the rows of the SSTable.

getDirectScanner

public SSTableScanner getDirectScanner()

Direct I/O SSTableScanner

Returns:

A Scanner for seeking over the rows of the SSTable.

getDirectScanner

public SSTableScanner getDirectScanner(Range range)

Direct I/O SSTableScanner over a defined range of tokens.

Parameters:

range - the range of keys to cover

Returns:

A Scanner for seeking over the rows of the SSTable.

getFileDataInput

public FileDataInput getFileDataInput(DecoratedKey decoratedKey,
                                      int bufferSize)

newSince

public boolean newSince(long age)

Tests if the sstable contains data newer than the given age param (in localhost currentMilli time). This works in conjunction with maxDataAge which is an upper bound on the create of data in this sstable.

Parameters:

age - The age to compare the maxDataAre of this sstable. Measured in millisec since epoc on this host

Returns:

True iff this sstable contains data that's newer than the given age parameter.

readRowSize

public static long readRowSize(java.io.DataInput in,
                               Descriptor d)
                        throws java.io.IOException

Throws:

java.io.IOException

createLinks

public void createLinks(java.lang.String snapshotDirectoryPath)
                 throws java.io.IOException

Throws:

java.io.IOException

decodeKey

public static DecoratedKey decodeKey(IPartitioner p,
                                     Descriptor d,
                                     java.nio.ByteBuffer bytes)

Conditionally use the deprecated 'IPartitioner.convertFromDiskFormat' method.

getBloomFilterFalsePositiveCount

public long getBloomFilterFalsePositiveCount()

getRecentBloomFilterFalsePositiveCount

public long getRecentBloomFilterFalsePositiveCount()

getBloomFilterTruePositiveCount

public long getBloomFilterTruePositiveCount()

getRecentBloomFilterTruePositiveCount

public long getRecentBloomFilterTruePositiveCount()

getKeyCache

public InstrumentingCache<Pair<Descriptor,DecoratedKey>,java.lang.Long> getKeyCache()

getEstimatedRowSize

public EstimatedHistogram getEstimatedRowSize()

getEstimatedColumnCount

public EstimatedHistogram getEstimatedColumnCount()

getReplayPosition

public ReplayPosition getReplayPosition()

getMaxTimestamp

public long getMaxTimestamp()

openDataReader

public RandomAccessReader openDataReader(boolean skipIOCache)
                                  throws java.io.IOException

Throws:

java.io.IOException

acquireReferences

public static boolean acquireReferences(java.lang.Iterable<SSTableReader> sstables)

Parameters:

sstables -

Returns:

true if all desired references were acquired. Otherwise, it will unreference any partial acquisition, and return false.

releaseReferences

public static void releaseReferences(java.lang.Iterable<SSTableReader> sstables)