org.apache.hadoop.hbase.regionserver

Class MultiVersionConsistencyControl

java.lang.Object

org.apache.hadoop.hbase.regionserver.MultiVersionConsistencyControl

@InterfaceAudience.Private
public class MultiVersionConsistencyControl
extends Object

Manages the read/write consistency within memstore. 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).

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	MultiVersionConsistencyControl.WriteEntry

Field Summary

Fields

Modifier and Type	Field and Description
static long	FIXED_SIZE

Constructor Summary

Constructors

Constructor and Description
MultiVersionConsistencyControl() Default constructor.

Method Summary

Methods

Modifier and Type	Method and Description
MultiVersionConsistencyControl.WriteEntry	beginMemstoreInsert() Generate and return a MultiVersionConsistencyControl.WriteEntry with a new write number.
void	completeMemstoreInsert(MultiVersionConsistencyControl.WriteEntry e) Complete a MultiVersionConsistencyControl.WriteEntry that was created by beginMemstoreInsert().
void	initialize(long startPoint) Initializes the memstoreRead/Write points appropriately.
long	memstoreReadPoint()
void	waitForRead(MultiVersionConsistencyControl.WriteEntry e) Wait for the global readPoint to advance upto the specified transaction number.

Methods inherited from class java.lang.Object

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

Field Detail

FIXED_SIZE

public static final long FIXED_SIZE

Constructor Detail

MultiVersionConsistencyControl

public MultiVersionConsistencyControl()

Default constructor. Initializes the memstoreRead/Write points to 0.

Method Detail

initialize

public void initialize(long startPoint)

Initializes the memstoreRead/Write points appropriately.

Parameters:

startPoint -

beginMemstoreInsert

public MultiVersionConsistencyControl.WriteEntry beginMemstoreInsert()

Generate and return a MultiVersionConsistencyControl.WriteEntry with a new write number. To complete the WriteEntry and wait for it to be visible, call completeMemstoreInsert(WriteEntry).

completeMemstoreInsert

public void completeMemstoreInsert(MultiVersionConsistencyControl.WriteEntry e)

Complete a MultiVersionConsistencyControl.WriteEntry that was created by beginMemstoreInsert(). 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.

waitForRead

public void waitForRead(MultiVersionConsistencyControl.WriteEntry e)

Wait for the global readPoint to advance upto the specified transaction number.

memstoreReadPoint

public long memstoreReadPoint()