Package org.apache.cassandra.service.paxos.uncommitted

Class PaxosBallotTracker

java.lang.Object

org.apache.cassandra.service.paxos.uncommitted.PaxosBallotTracker

public class PaxosBallotTracker
extends Object

Tracks the highest paxos ballot we've seen, and the lowest ballot we can accept. During paxos repair, the coordinator gets the highest ballot seen by each participant. At the end of repair, that high ballot is set as the new low bound. Combined with paxos repair during topology changes, this eliminates the possibility of new nodes accepting ballots that are before the most recently accepted ballot for a key.

Method Summary

Modifier and Type	Method	Description
void	flush()
File	getDirectory()
Ballot	getHighBound()
Ballot	getLowBound()
static PaxosBallotTracker	load(File directory)
void	onUpdate(Row row)
void	truncate()
static void	truncate(File directory)
void	updateLowBound(Ballot update)

Methods inherited from class java.lang.Object

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

Method Details

truncate

public static void truncate(File directory)
                     throws IOException

Throws:

IOException

load

public static PaxosBallotTracker load(File directory)
                               throws IOException

Throws:

IOException

flush

public void flush()
           throws IOException

Throws:

IOException

truncate

public void truncate()

onUpdate

public void onUpdate(Row row)

getDirectory

public File getDirectory()

updateLowBound

public void updateLowBound(Ballot update)
                    throws IOException

Throws:

IOException

getHighBound

public Ballot getHighBound()

getLowBound

public Ballot getLowBound()

Returns:

a unique ballot that has never been proposed, below which we will reject all proposals