org.apache.hadoop.hbase.regionserver

类 DefaultMemStore

java.lang.Object

org.apache.hadoop.hbase.regionserver.DefaultMemStore

所有已实现的接口:

HeapSize, MemStore

@InterfaceAudience.Private
public class DefaultMemStore
extends Object
implements MemStore

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.

嵌套类概要

嵌套类

限定符和类型	类和说明
protected static class	DefaultMemStore.MemStoreScanner

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

构造器概要

构造器

构造器和说明
DefaultMemStore() Default constructor.
DefaultMemStore(org.apache.hadoop.conf.Configuration conf, KeyValue.KVComparator c) Constructor.

方法概要

方法

限定符和类型	方法和说明
long	add(Cell cell) Write an update
long	add(Iterable<Cell> cells) Write the updates
void	clearSnapshot(long id) The passed snapshot was successfully persisted; it can be let go.
long	delete(Cell deleteCell) Write a delete
long	getFlushableSize() On flush, how much memory we will clear.
void	getRowKeyAtOrBefore(org.apache.hadoop.hbase.regionserver.GetClosestRowBeforeTracker state) Find the key that matches row exactly, or the one that immediately precedes it.
List<KeyValueScanner>	getScanners(long readPt)
long	getSnapshotSize() Return the size of the snapshot(s) if any
long	heapSize() Get the entire heap usage for this MemStore not including keys in the snapshot.
static void	main(String[] args) Code to help figure if our approximation of object heap sizes is close enough.
void	rollback(Cell cell) Remove n key from the memstore.
boolean	shouldSeek(Scan scan, Store store, long oldestUnexpiredTS) Check if this memstore may contain the required keys
long	size()
MemStoreSnapshot	snapshot() Creates a snapshot of the current memstore.
long	timeOfOldestEdit()
long	updateColumnValue(byte[] row, byte[] family, byte[] qualifier, long newValue, long now) Only used by tests.
long	upsert(Iterable<Cell> cells, long readpoint, List<Cell> removedCells) Update or insert the specified KeyValues.

从类继承的方法 java.lang.Object

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

字段详细资料

FIXED_OVERHEAD

public static final long FIXED_OVERHEAD

DEEP_OVERHEAD

public static final long DEEP_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,
               KeyValue.KVComparator c)

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 clearSnapshot(long)

指定者:

snapshot 在接口中 MemStore

返回:

MemStoreSnapshot

clearSnapshot

public void clearSnapshot(long id)
                   throws UnexpectedStateException

The passed snapshot was successfully persisted; it can be let go.

指定者:

clearSnapshot 在接口中 MemStore

参数:

id - Id of the snapshot to clean out.

抛出:

UnexpectedStateException

另请参阅:

snapshot()

getFlushableSize

public long getFlushableSize()

从接口复制的说明: MemStore

On flush, how much memory we will clear. 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.

指定者:

getFlushableSize 在接口中 MemStore

返回:

size of data that is going to be flushed

getSnapshotSize

public long getSnapshotSize()

从接口复制的说明: MemStore

Return the size of the snapshot(s) if any

指定者:

getSnapshotSize 在接口中 MemStore

返回:

size of the memstore snapshot

add

public long add(Cell cell)

Write an update

指定者:

add 在接口中 MemStore

参数:

cell -

返回:

approximate size of the passed cell.

add

public long add(Iterable<Cell> cells)

从接口复制的说明: MemStore

Write the updates

指定者:

add 在接口中 MemStore

返回:

approximate size of the passed cell.

timeOfOldestEdit

public long timeOfOldestEdit()

指定者:

timeOfOldestEdit 在接口中 MemStore

返回:

Oldest timestamp of all the Cells in the MemStore

rollback

public void rollback(Cell cell)

Remove n key from the memstore. Only cells that have the same key and the same memstoreTS are removed. It is ok to not update timeRangeTracker in this call. It is possible that we can optimize this method by using tailMap/iterator, but since this method is called rarely (only for error recovery), we can leave those optimization for the future.

指定者:

rollback 在接口中 MemStore

参数:

cell -

delete

public long delete(Cell deleteCell)

Write a delete

指定者:

delete 在接口中 MemStore

参数:

deleteCell -

返回:

approximate size of the passed key and value.

getRowKeyAtOrBefore

public void getRowKeyAtOrBefore(org.apache.hadoop.hbase.regionserver.GetClosestRowBeforeTracker state)

从接口复制的说明: MemStore

Find the key that matches row exactly, or the one that immediately precedes it. The target row key is set in state.

指定者:

getRowKeyAtOrBefore 在接口中 MemStore

参数:

state - column/delete tracking state

updateColumnValue

public long updateColumnValue(byte[] row,
                     byte[] family,
                     byte[] qualifier,
                     long newValue,
                     long now)

Only used by tests. TODO: Remove Given the specs of a column, update it, first by inserting a new record, then removing the old one. Since there is only 1 KeyValue involved, the memstoreTS will be set to 0, thus ensuring that they instantly appear to anyone. The underlying store will ensure that the insert/delete each are atomic. A scanner/reader will either get the new value, or the old value and all readers will eventually only see the new value after the old was removed.

指定者:

updateColumnValue 在接口中 MemStore

参数:

row -

family -

qualifier -

newValue -

now -

返回:

Timestamp

upsert

public long upsert(Iterable<Cell> cells,
          long readpoint,
          List<Cell> removedCells)

Update or insert the specified KeyValues.

For each KeyValue, insert into MemStore. This will atomically upsert the value for that row/family/qualifier. If a KeyValue did already exist, it will then be removed.

Currently the memstoreTS is kept at 0 so as each insert happens, it will be immediately visible. May want to change this so it is atomic across all KeyValues.

This is called under row lock, so Get operations will still see updates atomically. Scans will only see each KeyValue update as atomic.

指定者:

upsert 在接口中 MemStore

参数:

cells -

readpoint - readpoint below which we can safely remove duplicate KVs

removedCells - collect the removed cells. It can be null.

返回:

change in memstore size

getScanners

public List<KeyValueScanner> getScanners(long readPt)

指定者:

getScanners 在接口中 MemStore

返回:

scanner on memstore and snapshot in this order.

shouldSeek

public boolean shouldSeek(Scan scan,
                 Store store,
                 long oldestUnexpiredTS)

Check if this memstore may contain the required keys

参数:

scan - scan

store - holds reference to cf

oldestUnexpiredTS -

返回:

False if the key definitely does not exist in this Memstore

heapSize

public long heapSize()

Get the entire heap usage for this MemStore not including keys in the snapshot.

指定者:

heapSize 在接口中 HeapSize

size

public long size()

指定者:

size 在接口中 MemStore

返回:

Total memory occupied by this MemStore.

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