SSTableReader (apache-cassandra API)

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

All Implemented Interfaces:

RefCounted<SSTableReader>, SelfRefCounted<SSTableReader>

Direct Known Subclasses:

BigTableReader
```
public abstract class SSTableReader
extends SSTable
implements SelfRefCounted<SSTableReader>
```
An SSTableReader can be constructed in a number of places, but typically is either read from disk at startup, or constructed from a flushed memtable, or after compaction to replace some existing sstables. However once created, an sstablereader may also be modified. A reader's OpenReason describes its current stage in its lifecycle, as follows:
```
 
 NORMAL
 From:       None        => Reader has been read from disk, either at startup or from a flushed memtable
             EARLY       => Reader is the final result of a compaction
             MOVED_START => Reader WAS being compacted, but this failed and it has been restored to NORMAL status

 EARLY
 From:       None        => Reader is a compaction replacement that is either incomplete and has been opened
                            to represent its partial result status, or has been finished but the compaction
                            it is a part of has not yet completed fully
             EARLY       => Same as from None, only it is not the first time it has been

 MOVED_START
 From:       NORMAL      => Reader is being compacted. This compaction has not finished, but the compaction result
                            is either partially or fully opened, to either partially or fully replace this reader.
                            This reader's start key has been updated to represent this, so that reads only hit
                            one or the other reader.

 METADATA_CHANGE
 From:       NORMAL      => Reader has seen low traffic and the amount of memory available for index summaries is
                            constrained, so its index summary has been downsampled.
         METADATA_CHANGE => Same
  
```
Note that in parallel to this, there are two different Descriptor types; TMPLINK and FINAL; the latter corresponds to NORMAL state readers and all readers that replace a NORMAL one. TMPLINK is used for EARLY state readers and no others. When a reader is being compacted, if the result is large its replacement may be opened as EARLY before compaction completes in order to present the result to consumers earlier. In this case the reader will itself be changed to a MOVED_START state, where its start no longer represents its on-disk minimum key. This is to permit reads to be directed to only one reader when the two represent the same data. The EARLY file can represent a compaction result that is either partially complete and still in-progress, or a complete and immutable sstable that is part of a larger macro compaction action that has not yet fully completed. Currently ALL compaction results at least briefly go through an EARLY open state prior to completion, regardless of if early opening is enabled. Since a reader can be created multiple times over the same shared underlying resources, and the exact resources it shares between each instance differ subtly, we track the lifetime of any underlying resource with its own reference count, which each instance takes a Ref to. Each instance then tracks references to itself, and once these all expire it releases its Refs to these underlying resources. There is some shared cleanup behaviour needed only once all sstablereaders in a certain stage of their lifecycle (i.e. EARLY or NORMAL opening), and some that must only occur once all readers of any kind over a single logical sstable have expired. These are managed by the TypeTidy and GlobalTidy classes at the bottom, and are effectively managed as another resource each instance tracks its own Ref instance to, to ensure all of these resources are cleaned up safely and can be debugged otherwise. TODO: fill in details about Tracker and lifecycle interactions for tools, and for compaction strategies

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static class`	`SSTableReader.Factory`
`static class`	`SSTableReader.OpenReason`
`static class`	`SSTableReader.Operator` TODO: Move someplace reusable
`static class`	`SSTableReader.UniqueIdentifier`

Nested classes/interfaces inherited from interface org.apache.cassandra.utils.concurrent.RefCounted
RefCounted.Tidy

Field Summary

Fields
Modifier and Type	Field and Description
`protected IFilter`	`bf`
`protected BloomFilterTracker`	`bloomFilterTracker`
`protected FileHandle`	`dfile`
`static java.util.Comparator<SSTableReader>`	`generationReverseComparator`
`SerializationHeader`	`header`
`protected FileHandle`	`ifile`
`protected IndexSummary`	`indexSummary`
`SSTableReader.UniqueIdentifier`	`instanceId`
`protected java.util.concurrent.atomic.AtomicBoolean`	`isSuspect`
`protected InstrumentingCache<KeyCacheKey,RowIndexEntry>`	`keyCache`
`protected java.util.concurrent.atomic.AtomicLong`	`keyCacheHit`
`protected java.util.concurrent.atomic.AtomicLong`	`keyCacheRequest`
`long`	`maxDataAge` maxDataAge is a timestamp in local server time (e.g.
`static java.util.Comparator<SSTableReader>`	`maxTimestampAscending`
`static java.util.Comparator<SSTableReader>`	`maxTimestampDescending`
`SSTableReader.OpenReason`	`openReason`
`protected RowIndexEntry.IndexSerializer`	`rowIndexEntrySerializer`
`static java.util.Comparator<SSTableReader>`	`sizeComparator`
`static java.util.Comparator<SSTableReader>`	`sstableComparator`
`protected StatsMetadata`	`sstableMetadata`
`static com.google.common.collect.Ordering<SSTableReader>`	`sstableOrdering`

Fields inherited from class org.apache.cassandra.io.sstable.SSTable
components, compression, descriptor, first, last, metadata, optimizationStrategy, TOMBSTONE_HISTOGRAM_BIN_SIZE, TOMBSTONE_HISTOGRAM_SPOOL_SIZE, TOMBSTONE_HISTOGRAM_TTL_ROUND_SECONDS

Constructor Summary

Constructors
Modifier	Constructor and Description
`protected`	`SSTableReader(Descriptor desc, java.util.Set<Component> components, CFMetaData metadata, long maxDataAge, StatsMetadata sstableMetadata, SSTableReader.OpenReason openReason, SerializationHeader header)`

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`addTo(Ref.IdentityCollection identities)`
`void`	`cacheKey(DecoratedKey key, RowIndexEntry info)`
`SSTableReader`	`cloneWithNewStart(DecoratedKey newStart, java.lang.Runnable runOnClose)`
`SSTableReader`	`cloneWithNewSummarySamplingLevel(ColumnFamilyStore parent, int samplingLevel)` Returns a new SSTableReader with the same properties as this SSTableReader except that a new IndexSummary will be built at the target samplingLevel.
`SSTableReader`	`cloneWithRestoredStart(DecoratedKey restoredStart)`
`void`	`createLinks(java.lang.String snapshotDirectoryPath)`
`boolean`	`equals(java.lang.Object that)`
`static double`	`estimateCompactionGain(java.util.Set<SSTableReader> overlapping)` Estimates how much of the keys we would keep if the sstables were compacted together
`long`	`estimatedKeys()`
`long`	`estimatedKeysForRanges(java.util.Collection<Range<Token>> ranges)`
`DecoratedKey`	`firstKeyBeyond(PartitionPosition token)` Finds and returns the first key beyond a given token in this SSTable or null if no such key exists.
`void`	`forceFilterFailures()` For testing purposes only.
`static long`	`getApproximateKeyCount(java.lang.Iterable<SSTableReader> sstables)` Calculate approximate key count.
`int`	`getAvgColumnSetPerRow()`
`IFilter`	`getBloomFilter()`
`long`	`getBloomFilterFalsePositiveCount()`
`long`	`getBloomFilterOffHeapSize()` Returns the amount of memory in bytes used off heap by the bloom filter.
`long`	`getBloomFilterSerializedSize()`
`long`	`getBloomFilterTruePositiveCount()`
`RowIndexEntry`	`getCachedPosition(DecoratedKey key, boolean updateStats)`
`protected RowIndexEntry`	`getCachedPosition(KeyCacheKey unifiedKey, boolean updateStats)`
`KeyCacheKey`	`getCacheKey(DecoratedKey key)`
`CompressionMetadata`	`getCompressionMetadata()` Returns the compression metadata for this sstable.
`long`	`getCompressionMetadataOffHeapSize()` Returns the amount of memory in bytes used off heap by the compression meta-data.
`double`	`getCompressionRatio()`
`double`	`getCrcCheckChance()`
`long`	`getCreationTimeFor(Component component)`
`ChannelProxy`	`getDataChannel()`
`double`	`getDroppableTombstonesBefore(int gcBefore)`
`double`	`getEffectiveIndexInterval()`
`EstimatedHistogram`	`getEstimatedColumnCount()`
`double`	`getEstimatedDroppableTombstoneRatio(int gcBefore)`
`EstimatedHistogram`	`getEstimatedPartitionSize()`
`FileDataInput`	`getFileDataInput(long position)`
`java.lang.String`	`getFilename()`
`ChannelProxy`	`getIndexChannel()`
`FileHandle`	`getIndexFile()`
`long`	`getIndexScanPosition(PartitionPosition key)` Gets the position in the index file to start scanning to find the given key (at most indexInterval keys away, modulo downsampling of the index summary).
`static long`	`getIndexScanPositionFromBinarySearchResult(int binarySearchResult, IndexSummary referencedIndexSummary)`
`static int`	`getIndexSummaryIndexFromBinarySearchResult(int binarySearchResult)`
`byte[]`	`getIndexSummaryKey(int index)` Returns the key for the index summary entry at `index`.
`long`	`getIndexSummaryOffHeapSize()`
`int`	`getIndexSummarySamplingLevel()`
`int`	`getIndexSummarySize()` Returns the number of entries in the IndexSummary.
`InstrumentingCache<KeyCacheKey,RowIndexEntry>`	`getKeyCache()`
`long`	`getKeyCacheHit()`
`long`	`getKeyCacheRequest()`
`java.lang.Iterable<DecoratedKey>`	`getKeySamples(Range<Token> range)`
`int`	`getMaxIndexSummarySize()` Returns the approximate number of entries the IndexSummary would contain if it were at full sampling.
`int`	`getMaxLocalDeletionTime()`
`long`	`getMaxTimestamp()`
`int`	`getMaxTTL()`
`int`	`getMinIndexInterval()`
`int`	`getMinLocalDeletionTime()`
`long`	`getMinTimestamp()`
`int`	`getMinTTL()`
`RowIndexEntry`	`getPosition(PartitionPosition key, SSTableReader.Operator op)` Retrieves the position while updating the key cache and the stats.
`RowIndexEntry`	`getPosition(PartitionPosition key, SSTableReader.Operator op, boolean updateCacheAndStats)`
`protected abstract RowIndexEntry`	`getPosition(PartitionPosition key, SSTableReader.Operator op, boolean updateCacheAndStats, boolean permitMatchPastLast, SSTableReadsListener listener)`
`RowIndexEntry`	`getPosition(PartitionPosition key, SSTableReader.Operator op, SSTableReadsListener listener)` Retrieves the position while updating the key cache and the stats.
`java.util.List<Pair<java.lang.Long,java.lang.Long>>`	`getPositionsForRanges(java.util.Collection<Range<Token>> ranges)` Determine the minimal set of sections that can be extracted from this SSTable to cover the given ranges.
`RestorableMeter`	`getReadMeter()`
`long`	`getRecentBloomFilterFalsePositiveCount()`
`long`	`getRecentBloomFilterTruePositiveCount()`
`ISSTableScanner`	`getScanner()` I/O SSTableScanner
`abstract ISSTableScanner`	`getScanner(java.util.Collection<Range<Token>> ranges, com.google.common.util.concurrent.RateLimiter limiter)` Direct I/O SSTableScanner over a defined collection of ranges of tokens.
`ISSTableScanner`	`getScanner(ColumnFilter columns, DataRange dataRange, boolean isForThrift, SSTableReadsListener listener)`
`abstract ISSTableScanner`	`getScanner(ColumnFilter columns, DataRange dataRange, com.google.common.util.concurrent.RateLimiter limiter, boolean isForThrift, SSTableReadsListener listener)`
`abstract ISSTableScanner`	`getScanner(java.util.Iterator<AbstractBounds<PartitionPosition>> rangeIterator)` Direct I/O SSTableScanner over an iterator of bounds.
`ISSTableScanner`	`getScanner(Range<Token> range, com.google.common.util.concurrent.RateLimiter limiter)` Direct I/O SSTableScanner over a defined range of tokens.
`abstract ISSTableScanner`	`getScanner(com.google.common.util.concurrent.RateLimiter limiter)` Direct I/O SSTableScanner over the entirety of the sstable..
`int`	`getSSTableLevel()`
`StatsMetadata`	`getSSTableMetadata()`
`static long`	`getTotalBytes(java.lang.Iterable<SSTableReader> sstables)`
`long`	`getTotalColumnsSet()`
`long`	`getTotalRows()`
`static long`	`getTotalUncompressedBytes(java.lang.Iterable<SSTableReader> sstables)`
`int`	`hashCode()`
`void`	`incrementReadCount()` Increment the total read count and read rate for this SSTable.
`static SSTableReader`	`internalOpen(Descriptor desc, java.util.Set<Component> components, CFMetaData metadata, FileHandle ifile, FileHandle dfile, IndexSummary isummary, IFilter bf, long maxDataAge, StatsMetadata sstableMetadata, SSTableReader.OpenReason openReason, SerializationHeader header)` Open a RowIndexedReader which already has its state initialized (by SSTableWriter).
`boolean`	`isKeyCacheSetup()`
`boolean`	`isMarkedCompacted()`
`boolean`	`isMarkedSuspect()`
`boolean`	`isRepaired()`
`boolean`	`isReplaced()`
`abstract UnfilteredRowIterator`	`iterator(DecoratedKey key, Slices slices, ColumnFilter selectedColumns, boolean reversed, boolean isForThrift, SSTableReadsListener listener)`
`abstract UnfilteredRowIterator`	`iterator(FileDataInput file, DecoratedKey key, RowIndexEntry indexEntry, Slices slices, ColumnFilter selectedColumns, boolean reversed, boolean isForThrift)`
`DecoratedKey`	`keyAt(long indexPosition)`
`boolean`	`loadSummary()` Load index summary from Summary.db file if it exists.
`static void`	`logOpenException(Descriptor descriptor, java.io.IOException e)`
`void`	`markObsolete(java.lang.Runnable tidier)` Mark the sstable as obsolete, i.e., compacted into newer sstables.
`void`	`markSuspect()`
`boolean`	`mayHaveTombstones()` Whether the sstable may contain tombstones or if it is guaranteed to not contain any.
`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 descriptor)`
`static SSTableReader`	`open(Descriptor desc, CFMetaData metadata)`
`static SSTableReader`	`open(Descriptor descriptor, java.util.Set<Component> components, CFMetaData metadata)`
`static SSTableReader`	`open(Descriptor descriptor, java.util.Set<Component> components, CFMetaData metadata, boolean validate, boolean isOffline)` Open an SSTable for reading
`static java.util.Collection<SSTableReader>`	`openAll(java.util.Set<java.util.Map.Entry<Descriptor,java.util.Set<Component>>> entries, CFMetaData metadata)`
`RandomAccessReader`	`openDataReader()`
`RandomAccessReader`	`openDataReader(com.google.common.util.concurrent.RateLimiter limiter)`
`static SSTableReader`	`openForBatch(Descriptor descriptor, java.util.Set<Component> components, CFMetaData metadata)` Open SSTable reader to be used in batch mode(such as sstableloader).
`RandomAccessReader`	`openIndexReader()`
`static SSTableReader`	`openNoValidation(Descriptor descriptor, CFMetaData metadata)`
`static SSTableReader`	`openNoValidation(Descriptor descriptor, java.util.Set<Component> components, ColumnFamilyStore cfs)`
`void`	`overrideReadMeter(RestorableMeter readMeter)`
`Ref<SSTableReader>`	`ref()`
`void`	`releaseSummary()`
`void`	`reloadSSTableMetadata()` Reloads the sstable metadata from disk.
`static void`	`resetTidying()`
`void`	`runOnClose(java.lang.Runnable runOnClose)`
`void`	`saveBloomFilter()`
`static void`	`saveBloomFilter(Descriptor descriptor, IFilter filter)`
`void`	`saveSummary()` Save index summary to Summary.db file.
`static void`	`saveSummary(Descriptor descriptor, DecoratedKey first, DecoratedKey last, IndexSummary summary)` Save index summary to Summary.db file.
`Ref<SSTableReader>`	`selfRef()`
`void`	`setCrcCheckChance(double crcCheckChance)` Set the value of CRC check chance.
`void`	`setReplaced()`
`void`	`setupOnline()`
`static void`	`shutdownBlocking()`
`abstract UnfilteredRowIterator`	`simpleIterator(FileDataInput file, DecoratedKey key, RowIndexEntry indexEntry, boolean tombstoneOnly)`
`EncodingStats`	`stats()`
`Ref<SSTableReader>`	`tryRef()`
`long`	`uncompressedLength()`

Methods inherited from class org.apache.cassandra.io.sstable.SSTable
addComponents, appendTOC, bytesOnDisk, componentsFor, decorateKey, delete, discoverComponentsFor, estimateRowsFromIndex, getAllFilePaths, getColumnFamilyName, getIndexFilename, getKeyspaceName, getMinimalKey, getPartitioner, readTOC, toString, tryComponentFromFilename

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

maxTimestampDescending

public static final java.util.Comparator<SSTableReader> maxTimestampDescending

maxTimestampAscending

public static final java.util.Comparator<SSTableReader> maxTimestampAscending

sstableComparator

public static final java.util.Comparator<SSTableReader> sstableComparator

generationReverseComparator

public static final java.util.Comparator<SSTableReader> generationReverseComparator

sstableOrdering

public static final com.google.common.collect.Ordering<SSTableReader> sstableOrdering

sizeComparator

public static final java.util.Comparator<SSTableReader> sizeComparator

maxDataAge
```
public final long maxDataAge
```
maxDataAge is a timestamp in local server time (e.g. System.currentTimeMilli) which represents an upper 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 sstables. The age is in milliseconds since epoc and is local to this host.

openReason

public final SSTableReader.OpenReason openReason

instanceId

public final SSTableReader.UniqueIdentifier instanceId

ifile
```
protected FileHandle ifile
```

dfile
```
protected FileHandle dfile
```

indexSummary
```
protected IndexSummary indexSummary
```

bf
```
protected IFilter bf
```

rowIndexEntrySerializer

protected final RowIndexEntry.IndexSerializer rowIndexEntrySerializer

keyCache

protected InstrumentingCache<KeyCacheKey,RowIndexEntry> keyCache

bloomFilterTracker

protected final BloomFilterTracker bloomFilterTracker

isSuspect

protected final java.util.concurrent.atomic.AtomicBoolean isSuspect

sstableMetadata

protected volatile StatsMetadata sstableMetadata

header

public final SerializationHeader header

keyCacheHit

protected final java.util.concurrent.atomic.AtomicLong keyCacheHit

keyCacheRequest

protected final java.util.concurrent.atomic.AtomicLong keyCacheRequest

Constructor Detail

SSTableReader

protected SSTableReader(Descriptor desc,
                        java.util.Set<Component> components,
                        CFMetaData metadata,
                        long maxDataAge,
                        StatsMetadata sstableMetadata,
                        SSTableReader.OpenReason openReason,
                        SerializationHeader header)

Method Detail

getApproximateKeyCount
```
public static long getApproximateKeyCount(java.lang.Iterable<SSTableReader> sstables)
```
Calculate approximate key count. If cardinality estimator is available on all given sstables, then this method use them to estimate key count. If not, then this uses index summaries.

Parameters:

sstables - SSTables to calculate key count

Returns:

estimated key count

estimateCompactionGain
```
public static double estimateCompactionGain(java.util.Set<SSTableReader> overlapping)
```
Estimates how much of the keys we would keep if the sstables were compacted together

open

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

Throws:: java.io.IOException

openNoValidation

public static SSTableReader openNoValidation(Descriptor descriptor,
                                             java.util.Set<Component> components,
                                             ColumnFamilyStore cfs)
                                      throws java.io.IOException

Throws:: java.io.IOException

openNoValidation

public static SSTableReader openNoValidation(Descriptor descriptor,
                                             CFMetaData metadata)
                                      throws java.io.IOException

Throws:: java.io.IOException

openForBatch

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

Open SSTable reader to be used in batch mode(such as sstableloader).

Parameters:: descriptor -; components -; metadata -
Returns:: opened SSTableReader
Throws:: java.io.IOException

open
```
public static SSTableReader open(Descriptor descriptor,
                                 java.util.Set<Component> components,
                                 CFMetaData metadata,
                                 boolean validate,
                                 boolean isOffline)
                          throws java.io.IOException
```
Open an SSTable for reading

Parameters:

descriptor - SSTable to open

components - Components included with this SSTable

metadata - for this SSTables CF

validate - Check SSTable for corruption (limited)

isOffline - Whether we are opening this SSTable "offline", for example from an external tool or not for inclusion in queries (validations) This stops regenerating BF + Summaries and also disables tracking of hotness for the SSTable.

Returns:

SSTableReader

Throws:

java.io.IOException

logOpenException

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

openAll

public static java.util.Collection<SSTableReader> openAll(java.util.Set<java.util.Map.Entry<Descriptor,java.util.Set<Component>>> entries,
                                                          CFMetaData metadata)

internalOpen

public static SSTableReader internalOpen(Descriptor desc,
                                         java.util.Set<Component> components,
                                         CFMetaData metadata,
                                         FileHandle ifile,
                                         FileHandle dfile,
                                         IndexSummary isummary,
                                         IFilter bf,
                                         long maxDataAge,
                                         StatsMetadata sstableMetadata,
                                         SSTableReader.OpenReason openReason,
                                         SerializationHeader header)

Open a RowIndexedReader which already has its state initialized (by SSTableWriter).

getTotalBytes

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

getTotalUncompressedBytes

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

equals

public boolean equals(java.lang.Object that)

Overrides:: equals in class java.lang.Object

hashCode
```
public int hashCode()
```
Overrides:

hashCode in class java.lang.Object

getFilename
```
public java.lang.String getFilename()
```
Overrides:

getFilename in class SSTable

setupOnline
```
public void setupOnline()
```

isKeyCacheSetup
```
public boolean isKeyCacheSetup()
```

loadSummary
```
public boolean loadSummary()
```
Load index summary from Summary.db file if it exists. if loaded index summary has different index interval from current value stored in schema, then Summary.db file will be deleted and this returns false to rebuild summary.

Returns:

true if index summary is loaded successfully from Summary.db file.

saveSummary
```
public void saveSummary()
```
Save index summary to Summary.db file.

saveSummary

public static void saveSummary(Descriptor descriptor,
                               DecoratedKey first,
                               DecoratedKey last,
                               IndexSummary summary)

Save index summary to Summary.db file.

saveBloomFilter
```
public void saveBloomFilter()
```

saveBloomFilter

public static void saveBloomFilter(Descriptor descriptor,
                                   IFilter filter)

setReplaced
```
public void setReplaced()
```

isReplaced
```
public boolean isReplaced()
```

runOnClose

public void runOnClose(java.lang.Runnable runOnClose)

cloneWithRestoredStart

public SSTableReader cloneWithRestoredStart(DecoratedKey restoredStart)

cloneWithNewStart

public SSTableReader cloneWithNewStart(DecoratedKey newStart,
                                       java.lang.Runnable runOnClose)

cloneWithNewSummarySamplingLevel
```
public SSTableReader cloneWithNewSummarySamplingLevel(ColumnFamilyStore parent,
                                                      int samplingLevel)
                                               throws java.io.IOException
```
Returns a new SSTableReader with the same properties as this SSTableReader except that a new IndexSummary will be built at the target samplingLevel. This (original) SSTableReader instance will be marked as replaced, have its DeletingTask removed, and have its periodic read-meter sync task cancelled.

Parameters:

samplingLevel - the desired sampling level for the index summary on the new SSTableReader

Returns:

a new SSTableReader

Throws:

java.io.IOException

getReadMeter
```
public RestorableMeter getReadMeter()
```

getIndexSummarySamplingLevel

public int getIndexSummarySamplingLevel()

getIndexSummaryOffHeapSize

public long getIndexSummaryOffHeapSize()

getMinIndexInterval
```
public int getMinIndexInterval()
```

getEffectiveIndexInterval

public double getEffectiveIndexInterval()

releaseSummary
```
public void releaseSummary()
```

getIndexScanPosition
```
public long getIndexScanPosition(PartitionPosition key)
```
Gets the position in the index file to start scanning to find the given key (at most indexInterval keys away, modulo downsampling of the index summary). Always returns a value >= 0

getIndexScanPositionFromBinarySearchResult

public static long getIndexScanPositionFromBinarySearchResult(int binarySearchResult,
                                                              IndexSummary referencedIndexSummary)

getIndexSummaryIndexFromBinarySearchResult

public static int getIndexSummaryIndexFromBinarySearchResult(int binarySearchResult)

getCompressionMetadata
```
public CompressionMetadata getCompressionMetadata()
```
Returns the compression metadata for this sstable.

Throws:

java.lang.IllegalStateException - if the sstable is not compressed

getCompressionMetadataOffHeapSize
```
public long getCompressionMetadataOffHeapSize()
```
Returns the amount of memory in bytes used off heap by the compression meta-data.

Returns:

the amount of memory in bytes used off heap by the compression meta-data

forceFilterFailures
```
public void forceFilterFailures()
```
For testing purposes only.

getBloomFilter
```
public IFilter getBloomFilter()
```

getBloomFilterSerializedSize

public long getBloomFilterSerializedSize()

getBloomFilterOffHeapSize
```
public long getBloomFilterOffHeapSize()
```
Returns the amount of memory in bytes used off heap by the bloom filter.

Returns:

the amount of memory in bytes used off heap by the bloom filter

estimatedKeys
```
public long estimatedKeys()
```
Returns:

An estimate of the number of keys in this SSTable based on the index summary.

estimatedKeysForRanges
```
public long estimatedKeysForRanges(java.util.Collection<Range<Token>> ranges)
```
Parameters:

ranges -

Returns:

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

getIndexSummarySize
```
public int getIndexSummarySize()
```
Returns the number of entries in the IndexSummary. At full sampling, this is approximately 1/INDEX_INTERVALth of the keys in this SSTable.

getMaxIndexSummarySize
```
public int getMaxIndexSummarySize()
```
Returns the approximate number of entries the IndexSummary would contain if it were at full sampling.

getIndexSummaryKey
```
public byte[] getIndexSummaryKey(int index)
```
Returns the key for the index summary entry at `index`.

getKeySamples

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

getPositionsForRanges
```
public java.util.List<Pair<java.lang.Long,java.lang.Long>> getPositionsForRanges(java.util.Collection<Range<Token>> 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.

getCacheKey

public KeyCacheKey getCacheKey(DecoratedKey key)

cacheKey

public void cacheKey(DecoratedKey key,
                     RowIndexEntry info)

getCachedPosition

public RowIndexEntry getCachedPosition(DecoratedKey key,
                                       boolean updateStats)

getCachedPosition

protected RowIndexEntry getCachedPosition(KeyCacheKey unifiedKey,
                                          boolean updateStats)

getPosition
```
public final RowIndexEntry getPosition(PartitionPosition key,
                                       SSTableReader.Operator op)
```
Retrieves the position while updating the key cache and the stats.

Parameters:

key - The key to apply as the rhs to the given Operator. A 'fake' key is allowed to allow key selection by token bounds but only if op != * EQ

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

getPosition
```
public final RowIndexEntry getPosition(PartitionPosition key,
                                       SSTableReader.Operator op,
                                       SSTableReadsListener listener)
```
Retrieves the position while updating the key cache and the stats.

Parameters:

key - The key to apply as the rhs to the given Operator. A 'fake' key is allowed to allow key selection by token bounds but only if op != * EQ

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

listener - the SSTableReaderListener that must handle the notifications.

getPosition

public final RowIndexEntry getPosition(PartitionPosition key,
                                       SSTableReader.Operator op,
                                       boolean updateCacheAndStats)

getPosition

protected abstract RowIndexEntry getPosition(PartitionPosition key,
                                             SSTableReader.Operator op,
                                             boolean updateCacheAndStats,
                                             boolean permitMatchPastLast,
                                             SSTableReadsListener listener)

Parameters:: key - The key to apply as the rhs to the given Operator. A 'fake' key is allowed to allow key selection by token bounds but only if op != * EQ; op - The Operator defining matching keys: the nearest key to the target matching the operator wins.; updateCacheAndStats - true if updating stats and cache; listener - a listener used to handle internal events
Returns:: The index entry corresponding to the key, or null if the key is not present

iterator

public abstract UnfilteredRowIterator iterator(DecoratedKey key,
                                               Slices slices,
                                               ColumnFilter selectedColumns,
                                               boolean reversed,
                                               boolean isForThrift,
                                               SSTableReadsListener listener)

iterator

public abstract UnfilteredRowIterator iterator(FileDataInput file,
                                               DecoratedKey key,
                                               RowIndexEntry indexEntry,
                                               Slices slices,
                                               ColumnFilter selectedColumns,
                                               boolean reversed,
                                               boolean isForThrift)

simpleIterator

public abstract UnfilteredRowIterator simpleIterator(FileDataInput file,
                                                     DecoratedKey key,
                                                     RowIndexEntry indexEntry,
                                                     boolean tombstoneOnly)

firstKeyBeyond
```
public DecoratedKey firstKeyBeyond(PartitionPosition token)
```
Finds and returns the first key beyond a given token in this SSTable or null if no such key exists.

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())

getCrcCheckChance
```
public double getCrcCheckChance()
```

setCrcCheckChance
```
public void setCrcCheckChance(double crcCheckChance)
```
Set the value of CRC check chance. The argument supplied is obtained from the the property of the owning CFS. Called when either the SSTR is initialized, or the CFS's property is updated via JMX

Parameters:

crcCheckChance -

markObsolete
```
public void markObsolete(java.lang.Runnable tidier)
```
Mark the sstable as obsolete, i.e., compacted into newer sstables. When calling this function, the caller must ensure that the SSTableReader is not referenced anywhere except for threads holding a reference. multiple times is usually buggy (see exceptions in Tracker.unmarkCompacting and removeOldSSTablesSize).

isMarkedCompacted
```
public boolean isMarkedCompacted()
```

markSuspect
```
public void markSuspect()
```

isMarkedSuspect
```
public boolean isMarkedSuspect()
```

getScanner
```
public ISSTableScanner getScanner()
```
I/O SSTableScanner

Returns:

A Scanner for seeking over the rows of the SSTable.

getScanner

public ISSTableScanner getScanner(ColumnFilter columns,
                                  DataRange dataRange,
                                  boolean isForThrift,
                                  SSTableReadsListener listener)

Parameters:: columns - the columns to return.; dataRange - filter to use when reading the columns; listener - a listener used to handle internal read events
Returns:: A Scanner for seeking over the rows of the SSTable.

getScanner
```
public ISSTableScanner getScanner(Range<Token> range,
                                  com.google.common.util.concurrent.RateLimiter limiter)
```
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.

getScanner
```
public abstract ISSTableScanner getScanner(com.google.common.util.concurrent.RateLimiter limiter)
```
Direct I/O SSTableScanner over the entirety of the sstable..

Returns:

A Scanner over the full content of the SSTable.

getScanner

public abstract ISSTableScanner getScanner(java.util.Collection<Range<Token>> ranges,
                                           com.google.common.util.concurrent.RateLimiter limiter)

Direct I/O SSTableScanner over a defined collection of ranges of tokens.

Parameters:: ranges - the range of keys to cover
Returns:: A Scanner for seeking over the rows of the SSTable.

getScanner
```
public abstract ISSTableScanner getScanner(java.util.Iterator<AbstractBounds<PartitionPosition>> rangeIterator)
```
Direct I/O SSTableScanner over an iterator of bounds.

Parameters:

rangeIterator - the keys to cover

Returns:

A Scanner for seeking over the rows of the SSTable.

getScanner

public abstract ISSTableScanner getScanner(ColumnFilter columns,
                                           DataRange dataRange,
                                           com.google.common.util.concurrent.RateLimiter limiter,
                                           boolean isForThrift,
                                           SSTableReadsListener listener)

Parameters:: columns - the columns to return.; dataRange - filter to use when reading the columns; listener - a listener used to handle internal read events
Returns:: A Scanner for seeking over the rows of the SSTable.

getFileDataInput

public FileDataInput getFileDataInput(long position)

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.

createLinks

public void createLinks(java.lang.String snapshotDirectoryPath)

isRepaired
```
public boolean isRepaired()
```

keyAt

public DecoratedKey keyAt(long indexPosition)
                   throws java.io.IOException

Throws:: java.io.IOException

getBloomFilterFalsePositiveCount

public long getBloomFilterFalsePositiveCount()

getRecentBloomFilterFalsePositiveCount

public long getRecentBloomFilterFalsePositiveCount()

getBloomFilterTruePositiveCount

public long getBloomFilterTruePositiveCount()

getRecentBloomFilterTruePositiveCount

public long getRecentBloomFilterTruePositiveCount()

getKeyCache

public InstrumentingCache<KeyCacheKey,RowIndexEntry> getKeyCache()

getEstimatedPartitionSize

public EstimatedHistogram getEstimatedPartitionSize()

getEstimatedColumnCount

public EstimatedHistogram getEstimatedColumnCount()

getEstimatedDroppableTombstoneRatio

public double getEstimatedDroppableTombstoneRatio(int gcBefore)

getDroppableTombstonesBefore

public double getDroppableTombstonesBefore(int gcBefore)

getCompressionRatio
```
public double getCompressionRatio()
```

getMinTimestamp
```
public long getMinTimestamp()
```

getMaxTimestamp
```
public long getMaxTimestamp()
```

getMinLocalDeletionTime
```
public int getMinLocalDeletionTime()
```

getMaxLocalDeletionTime
```
public int getMaxLocalDeletionTime()
```

mayHaveTombstones
```
public boolean mayHaveTombstones()
```
Whether the sstable may contain tombstones or if it is guaranteed to not contain any.
Note that having that method return false guarantees the sstable has no tombstones whatsoever (so no cell tombstone, no range tombstone maker and no expiring columns), but having it return true doesn't guarantee it contains any as 1) it may simply have non-expired cells and 2) old-format sstables didn't contain enough information to decide this and so always return true.

getMinTTL
```
public int getMinTTL()
```

getMaxTTL
```
public int getMaxTTL()
```

getTotalColumnsSet
```
public long getTotalColumnsSet()
```

getTotalRows
```
public long getTotalRows()
```

getAvgColumnSetPerRow
```
public int getAvgColumnSetPerRow()
```

getSSTableLevel
```
public int getSSTableLevel()
```

reloadSSTableMetadata
```
public void reloadSSTableMetadata()
                           throws java.io.IOException
```
Reloads the sstable metadata from disk. Called after level is changed on sstable, for example if the sstable is dropped to L0 Might be possible to remove in future versions

Throws:

java.io.IOException

getSSTableMetadata

public StatsMetadata getSSTableMetadata()

openDataReader

public RandomAccessReader openDataReader(com.google.common.util.concurrent.RateLimiter limiter)

openDataReader

public RandomAccessReader openDataReader()

openIndexReader

public RandomAccessReader openIndexReader()

getDataChannel
```
public ChannelProxy getDataChannel()
```

getIndexChannel
```
public ChannelProxy getIndexChannel()
```

getIndexFile
```
public FileHandle getIndexFile()
```

getCreationTimeFor
```
public long getCreationTimeFor(Component component)
```
Parameters:

component - component to get timestamp.

Returns:

last modified time for given component. 0 if given component does not exist or IO error occurs.

getKeyCacheHit
```
public long getKeyCacheHit()
```
Returns:

Number of key cache hit

getKeyCacheRequest
```
public long getKeyCacheRequest()
```
Returns:

Number of key cache request

incrementReadCount
```
public void incrementReadCount()
```
Increment the total read count and read rate for this SSTable. This should not be incremented for non-query reads, like compaction.

stats
```
public EncodingStats stats()
```

tryRef
```
public Ref<SSTableReader> tryRef()
```
Specified by:

tryRef in interface RefCounted<SSTableReader>

Returns:

the a new Ref() to the managed object, incrementing its refcount, or null if it is already released

selfRef
```
public Ref<SSTableReader> selfRef()
```
Specified by:

selfRef in interface SelfRefCounted<SSTableReader>

ref
```
public Ref<SSTableReader> ref()
```
Specified by:

ref in interface RefCounted<SSTableReader>

overrideReadMeter

public void overrideReadMeter(RestorableMeter readMeter)

addTo

public void addTo(Ref.IdentityCollection identities)

resetTidying
```
public static void resetTidying()
```

shutdownBlocking

public static void shutdownBlocking()
                             throws java.lang.InterruptedException

Throws:: java.lang.InterruptedException

Class SSTableReader

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.cassandra.utils.concurrent.RefCounted

Field Summary

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

Constructor Summary

Method Summary

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

Methods inherited from class java.lang.Object

Field Detail

maxTimestampDescending

maxTimestampAscending

sstableComparator

generationReverseComparator

sstableOrdering

sizeComparator

maxDataAge

openReason

instanceId

ifile

dfile

indexSummary

bf

rowIndexEntrySerializer

keyCache

bloomFilterTracker

isSuspect

sstableMetadata

header

keyCacheHit

keyCacheRequest

Constructor Detail

SSTableReader

Method Detail

getApproximateKeyCount

estimateCompactionGain

open

open

open

openNoValidation

openNoValidation

openForBatch

open

logOpenException

openAll

internalOpen

getTotalBytes

getTotalUncompressedBytes

equals

hashCode

getFilename

setupOnline

isKeyCacheSetup

loadSummary

saveSummary

saveSummary

saveBloomFilter

saveBloomFilter

setReplaced

isReplaced

runOnClose

cloneWithRestoredStart

cloneWithNewStart

cloneWithNewSummarySamplingLevel

getReadMeter

getIndexSummarySamplingLevel

getIndexSummaryOffHeapSize

getMinIndexInterval

getEffectiveIndexInterval

releaseSummary

getIndexScanPosition

getIndexScanPositionFromBinarySearchResult

getIndexSummaryIndexFromBinarySearchResult

getCompressionMetadata

getCompressionMetadataOffHeapSize

forceFilterFailures

getBloomFilter

getBloomFilterSerializedSize

getBloomFilterOffHeapSize

estimatedKeys