org.apache.hadoop.hbase.regionserver

类 MultiVersionConcurrencyControl

java.lang.Object

org.apache.hadoop.hbase.regionserver.MultiVersionConcurrencyControl

@InterfaceAudience.Private
public class MultiVersionConcurrencyControl
extends Object

Manages the read/write consistency. This provides an interface for readers to determine what entries to ignore, and a mechanism for writers to obtain new write numbers, then "commit" the new writes for readers to read (thus forming atomic transactions).

嵌套类概要

嵌套类

限定符和类型	类和说明
static class	MultiVersionConcurrencyControl.WriteEntry Write number and whether write has completed given out at start of a write transaction.

字段概要

字段

限定符和类型	字段和说明
static long	FIXED_SIZE
static long	NONE Represents no value, or not set.

构造器概要

构造器

构造器和说明
MultiVersionConcurrencyControl()
MultiVersionConcurrencyControl(long startPoint) Construct and set read point.

方法概要

方法

限定符和类型	方法和说明
void	advanceTo(long newStartPoint) Step the MVCC forward on to a new read/write basis.
void	await() Wait until the read point catches up to the write point; i.e. wait on all outstanding mvccs to complete.
MultiVersionConcurrencyControl.WriteEntry	begin() Call begin(Runnable) with an empty Runnable.
MultiVersionConcurrencyControl.WriteEntry	begin(Runnable action) Start a write transaction.
boolean	complete(MultiVersionConcurrencyControl.WriteEntry writeEntry) Mark the MultiVersionConcurrencyControl.WriteEntry as complete and advance the read point as much as possible.
void	completeAndWait(MultiVersionConcurrencyControl.WriteEntry e) Complete a MultiVersionConcurrencyControl.WriteEntry that was created by begin() then wait until the read point catches up to our write.
long	getReadPoint()
long	getWritePoint()
String	toString()

从类继承的方法 java.lang.Object

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

字段详细资料

NONE

public static final long NONE

Represents no value, or not set.

另请参阅:

常量字段值

FIXED_SIZE

public static final long FIXED_SIZE

构造器详细资料

MultiVersionConcurrencyControl

public MultiVersionConcurrencyControl()

MultiVersionConcurrencyControl

public MultiVersionConcurrencyControl(long startPoint)

Construct and set read point. Write point is uninitialized.

方法详细资料

advanceTo

public void advanceTo(long newStartPoint)

Step the MVCC forward on to a new read/write basis.

参数:

newStartPoint -

begin

public MultiVersionConcurrencyControl.WriteEntry begin()

Call begin(Runnable) with an empty Runnable.

begin

public MultiVersionConcurrencyControl.WriteEntry begin(Runnable action)

Start a write transaction. Create a new MultiVersionConcurrencyControl.WriteEntry with a new write number and add it to our queue of ongoing writes. Return this WriteEntry instance. To complete the write transaction and wait for it to be visible, call completeAndWait(WriteEntry). If the write failed, call complete(WriteEntry) so we can clean up AFTER removing ALL trace of the failed write transaction.

The action will be executed under the lock which means it can keep the same order with mvcc.

另请参阅:

complete(WriteEntry), completeAndWait(WriteEntry)

await

public void await()

Wait until the read point catches up to the write point; i.e. wait on all outstanding mvccs to complete.

completeAndWait

public void completeAndWait(MultiVersionConcurrencyControl.WriteEntry e)

Complete a MultiVersionConcurrencyControl.WriteEntry that was created by begin() then wait until the read point catches up to our write. At the end of this call, the global read point is at least as large as the write point of the passed in WriteEntry. Thus, the write is visible to MVCC readers.

complete

public boolean complete(MultiVersionConcurrencyControl.WriteEntry writeEntry)

Mark the MultiVersionConcurrencyControl.WriteEntry as complete and advance the read point as much as possible. Call this even if the write has FAILED (AFTER backing out the write transaction changes completely) so we can clean up the outstanding transaction. How much is the read point advanced? Let S be the set of all write numbers that are completed. Set the read point to the highest numbered write of S.

参数:

writeEntry -

返回:

true if e is visible to MVCC readers (that is, readpoint >= e.writeNumber)

toString

public String toString()

覆盖:

toString 在类中 Object

getReadPoint

public long getReadPoint()

getWritePoint

public long getWritePoint()