org.apache.hadoop.hbase.regionserver

Class MemStoreSnapshot

java.lang.Object

org.apache.hadoop.hbase.regionserver.MemStoreSnapshot

@InterfaceAudience.Private
public class MemStoreSnapshot
extends Object

MemStoreSnapshot is a Context Object to hold details of the snapshot taken on a MemStore. Details include the snapshot's identifier, count of cells in it and total memory size occupied by all the cells, timestamp information of all the cells and the snapshot immutableSegment.

NOTE:Every time when getScanners() is called, we create new SnapshotSegmentScanners on the snapshotImmutableSegment,and Segment.incScannerCount() is invoked in the SnapshotSegmentScanner ctor to increase the reference count of MemStoreLAB which used by snapshotImmutableSegment, so after we finish using these scanners, we must call their close method to invoke Segment.decScannerCount().

Constructor Summary

Constructors

Constructor and Description
MemStoreSnapshot(long id, ImmutableSegment snapshot)

Method Summary

Modifier and Type	Method and Description
int	getCellsCount() Returns Number of Cells in this snapshot.
long	getDataSize()
long	getId() Returns snapshot's identifier.
MemStoreSize	getMemStoreSize()
List<KeyValueScanner>	getScanners() Create new SnapshotSegmentScanners for iterating over the snapshot.
TimeRangeTracker	getTimeRangeTracker() Returns TimeRangeTracker for all the Cells in the snapshot.
boolean	isTagsPresent() Returns true if tags are present in this snapshot

Methods inherited from class java.lang.Object

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

Constructor Detail

MemStoreSnapshot

public MemStoreSnapshot(long id,
                        ImmutableSegment snapshot)

Method Detail

getId

public long getId()

Returns snapshot's identifier.

getCellsCount

public int getCellsCount()

Returns Number of Cells in this snapshot.

getDataSize

public long getDataSize()

getMemStoreSize

public MemStoreSize getMemStoreSize()

getTimeRangeTracker

public TimeRangeTracker getTimeRangeTracker()

Returns TimeRangeTracker for all the Cells in the snapshot.

getScanners

public List<KeyValueScanner> getScanners()

Create new SnapshotSegmentScanners for iterating over the snapshot.
NOTE:Here when create new SnapshotSegmentScanners, Segment.incScannerCount() is invoked in the SnapshotSegmentScanner ctor,so after we use these SnapshotSegmentScanners, we must call SnapshotSegmentScanner.close() to invoke Segment.decScannerCount().

Returns:

KeyValueScanners(Which type is SnapshotSegmentScanner) for iterating over the snapshot.

isTagsPresent

public boolean isTagsPresent()

Returns true if tags are present in this snapshot