org.apache.hadoop.hbase.regionserver

Class Segment

java.lang.Object

org.apache.hadoop.hbase.regionserver.Segment

Direct Known Subclasses:

ImmutableSegment, MutableSegment

@InterfaceAudience.Private
public abstract class Segment
extends Object

This is an abstraction of a segment maintained in a memstore, e.g., the active cell set or its snapshot. This abstraction facilitates the management of the compaction pipeline and the shifts of these segments from active set to snapshot set in the default implementation.

Field Summary

Fields

Modifier and Type	Field and Description
protected AtomicLong	dataSize
static long	DEEP_OVERHEAD
static long	FIXED_OVERHEAD
protected AtomicLong	heapSize
protected long	minSequenceId
protected boolean	tagsPresent
protected TimeRangeTracker	timeRangeTracker

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Segment(CellComparator comparator)
protected	Segment(CellSet cellSet, CellComparator comparator, MemStoreLAB memStoreLAB)
protected	Segment(Segment segment)

Method Summary

Modifier and Type	Method and Description
void	close() Closing a segment before it is being discarded
int	compare(Cell left, Cell right)
int	compareRows(Cell left, Cell right)
void	decScannerCount()
int	getCellsCount()
protected CellSet	getCellSet()
protected CellComparator	getComparator() Returns the Cell comparator used by this segment
Cell	getFirstAfter(Cell cell)
long	getMinSequenceId()
abstract long	getMinTimestamp()
protected KeyValueScanner	getScanner(long readPoint) Creates the scanner for the given read point
KeyValueScanner	getScanner(long readPoint, long order) Creates the scanner for the given read point, and a specific order in a list
List<KeyValueScanner>	getScanners(long readPoint, long order)
TimeRangeTracker	getTimeRangeTracker()
SortedSet<Cell>	headSet(Cell firstKeyOnRow)
long	heapSize()
protected long	heapSizeChange(Cell cell, boolean succ)
void	incScannerCount()
protected void	incSize(long delta, long heapOverhead) Updates the size counters of the segment by the given delta
protected void	internalAdd(Cell cell, boolean mslabUsed, MemstoreSize memstoreSize)
boolean	isEmpty()
boolean	isTagsPresent()
Iterator<Cell>	iterator()
long	keySize()
Cell	last()
Cell	maybeCloneWithAllocator(Cell cell) If the segment has a memory allocator the cell is being cloned to this space, and returned; otherwise the given cell is returned
protected Segment	setCellSet(CellSet cellSetOld, CellSet cellSetNew) Setting the CellSet of the segment - used only for flat immutable segment for setting immutable CellSet after its creation in immutable segment constructor
abstract boolean	shouldSeek(TimeRange tr, long oldestUnexpiredTS)
protected SortedSet<Cell>	tailSet(Cell firstCell) Returns a subset of the segment cell set, which starts with the given cell
String	toString()
protected void	updateMetaInfo(Cell cellToAdd, boolean succ, boolean mslabUsed, MemstoreSize memstoreSize)

Methods inherited from class java.lang.Object

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

Field Detail

FIXED_OVERHEAD

public static final long FIXED_OVERHEAD

DEEP_OVERHEAD

public static final long DEEP_OVERHEAD

minSequenceId

protected long minSequenceId

dataSize

protected final AtomicLong dataSize

heapSize

protected final AtomicLong heapSize

timeRangeTracker

protected final TimeRangeTracker timeRangeTracker

tagsPresent

protected volatile boolean tagsPresent

Constructor Detail

Segment

protected Segment(CellComparator comparator)

Segment

protected Segment(CellSet cellSet,
                  CellComparator comparator,
                  MemStoreLAB memStoreLAB)

Segment

protected Segment(Segment segment)

Method Detail

getScanner

protected KeyValueScanner getScanner(long readPoint)

Creates the scanner for the given read point

Returns:

a scanner for the given read point

getScanner

public KeyValueScanner getScanner(long readPoint,
                                  long order)

Creates the scanner for the given read point, and a specific order in a list

Returns:

a scanner for the given read point

getScanners

public List<KeyValueScanner> getScanners(long readPoint,
                                         long order)

isEmpty

public boolean isEmpty()

Returns:

whether the segment has any cells

getCellsCount

public int getCellsCount()

Returns:

number of cells in segment

getFirstAfter

public Cell getFirstAfter(Cell cell)

Returns:

the first cell in the segment that has equal or greater key than the given cell

close

public void close()

Closing a segment before it is being discarded

maybeCloneWithAllocator

public Cell maybeCloneWithAllocator(Cell cell)

If the segment has a memory allocator the cell is being cloned to this space, and returned; otherwise the given cell is returned

Returns:

either the given cell or its clone

shouldSeek

public abstract boolean shouldSeek(TimeRange tr,
                                   long oldestUnexpiredTS)

getMinTimestamp

public abstract long getMinTimestamp()

isTagsPresent

public boolean isTagsPresent()

incScannerCount

public void incScannerCount()

decScannerCount

public void decScannerCount()

setCellSet

protected Segment setCellSet(CellSet cellSetOld,
                             CellSet cellSetNew)

Setting the CellSet of the segment - used only for flat immutable segment for setting immutable CellSet after its creation in immutable segment constructor

Returns:

this object

keySize

public long keySize()

Returns:

Sum of all cell's size.

heapSize

public long heapSize()

Returns:

The heap size of this segment.

incSize

protected void incSize(long delta,
                       long heapOverhead)

Updates the size counters of the segment by the given delta

getMinSequenceId

public long getMinSequenceId()

getTimeRangeTracker

public TimeRangeTracker getTimeRangeTracker()

last

public Cell last()

iterator

public Iterator<Cell> iterator()

headSet

public SortedSet<Cell> headSet(Cell firstKeyOnRow)

compare

public int compare(Cell left,
                   Cell right)

compareRows

public int compareRows(Cell left,
                       Cell right)

getCellSet

protected CellSet getCellSet()

Returns:

a set of all cells in the segment

getComparator

protected CellComparator getComparator()

Returns the Cell comparator used by this segment

Returns:

the Cell comparator used by this segment

internalAdd

protected void internalAdd(Cell cell,
                           boolean mslabUsed,
                           MemstoreSize memstoreSize)

updateMetaInfo

protected void updateMetaInfo(Cell cellToAdd,
                              boolean succ,
                              boolean mslabUsed,
                              MemstoreSize memstoreSize)

heapSizeChange

protected long heapSizeChange(Cell cell,
                              boolean succ)

Returns:

The increase in heap size because of this cell addition. This includes this cell POJO's heap size itself and additional overhead because of addition on to CSLM.

tailSet

protected SortedSet<Cell> tailSet(Cell firstCell)

Returns a subset of the segment cell set, which starts with the given cell

Parameters:

firstCell - a cell in the segment

Returns:

a subset of the segment cell set, which starts with the given cell

toString

public String toString()

Overrides:

toString in class Object