org.apache.hadoop.hbase.regionserver

类 DefaultMemStore

java.lang.Object

org.apache.hadoop.hbase.regionserver.AbstractMemStore

org.apache.hadoop.hbase.regionserver.DefaultMemStore

所有已实现的接口:

MemStore

@InterfaceAudience.Private
public class DefaultMemStore
extends AbstractMemStore

The MemStore holds in-memory modifications to the Store. Modifications are Cells. When asked to flush, current memstore is moved to snapshot and is cleared. We continue to serve edits out of new memstore and backing snapshot until flusher reports in that the flush succeeded. At this point we let the snapshot go.

The MemStore functions should not be called in parallel. Callers should hold write and read locks. This is done in HStore.

TODO: Adjust size of the memstore when we remove items because they have been deleted. TODO: With new KVSLS, need to make sure we update HeapSize with difference in KV size.

字段概要

字段

限定符和类型	字段和说明
static long	DEEP_OVERHEAD
static long	FIXED_OVERHEAD

从类继承的字段 org.apache.hadoop.hbase.regionserver.AbstractMemStore

active, regionServices, snapshot, snapshotId

构造器概要

构造器

构造器和说明
DefaultMemStore() Default constructor.
DefaultMemStore(org.apache.hadoop.conf.Configuration conf, CellComparator c) Constructor.
DefaultMemStore(org.apache.hadoop.conf.Configuration conf, CellComparator c, RegionServicesForStores regionServices) Constructor.

方法概要

限定符和类型	方法和说明
protected void	checkActiveSize() Check whether anything need to be done based on the current active set size Nothing need to be done for the DefaultMemStore
MemStoreSize	getFlushableSize() Flush will first clear out the data in snapshot if any (It will take a second flush invocation to clear the current Cell set).
List<KeyValueScanner>	getScanners(long readPt)
protected List<Segment>	getSegments()
protected long	heapSize()
boolean	isSloppy()
protected long	keySize()
static void	main(String[] args) Code to help figure if our approximation of object heap sizes is close enough.
long	preFlushSeqIDEstimation() This method is called before the flush is executed.
MemStoreSize	size()
MemStoreSnapshot	snapshot() Creates a snapshot of the current memstore.
void	updateLowestUnflushedSequenceIdInWAL(boolean onlyIfMoreRecent) Updates the wal with the lowest sequence id (oldest entry) that is still in memory

从类继承的方法 org.apache.hadoop.hbase.regionserver.AbstractMemStore

add, add, addToScanners, addToScanners, clearSnapshot, dump, getComparator, getConfiguration, getLowest, getNextRow, getSnapshotSize, resetActive, timeOfOldestEdit, toString, upsert

从类继承的方法 java.lang.Object

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

从接口继承的方法 org.apache.hadoop.hbase.regionserver.MemStore

startReplayingFromWAL, stopReplayingFromWAL

字段详细资料

DEEP_OVERHEAD

public static final long DEEP_OVERHEAD

FIXED_OVERHEAD

public static final long FIXED_OVERHEAD

构造器详细资料

DefaultMemStore

public DefaultMemStore()

Default constructor. Used for tests.

DefaultMemStore

public DefaultMemStore(org.apache.hadoop.conf.Configuration conf,
                       CellComparator c)

Constructor.

参数:

c - Comparator

DefaultMemStore

public DefaultMemStore(org.apache.hadoop.conf.Configuration conf,
                       CellComparator c,
                       RegionServicesForStores regionServices)

Constructor.

参数:

c - Comparator

方法详细资料

snapshot

public MemStoreSnapshot snapshot()

Creates a snapshot of the current memstore. Snapshot must be cleared by call to AbstractMemStore.clearSnapshot(long)

返回:

MemStoreSnapshot

getFlushableSize

public MemStoreSize getFlushableSize()

从接口复制的说明: MemStore

Flush will first clear out the data in snapshot if any (It will take a second flush invocation to clear the current Cell set). If snapshot is empty, current Cell set will be flushed.

返回:

On flush, how much memory we will clear.

keySize

protected long keySize()

指定者:

keySize 在类中 AbstractMemStore

返回:

The total size of cells in this memstore. We will not consider cells in the snapshot

heapSize

protected long heapSize()

指定者:

heapSize 在类中 AbstractMemStore

返回:

The total heap size of cells in this memstore. We will not consider cells in the snapshot

getScanners

public List<KeyValueScanner> getScanners(long readPt)
                                  throws IOException

返回:

scanner over the memstore. This might include scanner over the snapshot when one is present.

抛出:

IOException

getSegments

protected List<Segment> getSegments()
                             throws IOException

指定者:

getSegments 在类中 AbstractMemStore

返回:

an ordered list of segments from most recent to oldest in memstore

抛出:

IOException

updateLowestUnflushedSequenceIdInWAL

public void updateLowestUnflushedSequenceIdInWAL(boolean onlyIfMoreRecent)

从类复制的说明: AbstractMemStore

Updates the wal with the lowest sequence id (oldest entry) that is still in memory

指定者:

updateLowestUnflushedSequenceIdInWAL 在类中 AbstractMemStore

参数:

onlyIfMoreRecent - a flag that marks whether to update the sequence id no matter what or only if it is greater than the previous sequence id

size

public MemStoreSize size()

返回:

Total memory occupied by this MemStore. This won't include any size occupied by the snapshot. We assume the snapshot will get cleared soon. This is not thread safe and the memstore may be changed while computing its size. It is the responsibility of the caller to make sure this doesn't happen.

checkActiveSize

protected void checkActiveSize()

Check whether anything need to be done based on the current active set size Nothing need to be done for the DefaultMemStore

指定者:

checkActiveSize 在类中 AbstractMemStore

preFlushSeqIDEstimation

public long preFlushSeqIDEstimation()

从接口复制的说明: MemStore

This method is called before the flush is executed.

返回:

an estimation (lower bound) of the unflushed sequence id in memstore after the flush is executed. if memstore will be cleared returns HConstants.NO_SEQNUM.

isSloppy

public boolean isSloppy()

main

public static void main(String[] args)

Code to help figure if our approximation of object heap sizes is close enough. See hbase-900. Fills memstores then waits so user can heap dump and bring up resultant hprof in something like jprofiler which allows you get 'deep size' on objects.

参数:

args - main args