org.apache.flink.runtime.checkpoint

Class ZooKeeperCheckpointIDCounter

java.lang.Object

org.apache.flink.runtime.checkpoint.ZooKeeperCheckpointIDCounter

All Implemented Interfaces:

CheckpointIDCounter

public class ZooKeeperCheckpointIDCounter
extends Object
implements CheckpointIDCounter

CheckpointIDCounter instances for JobManagers running in RecoveryMode.ZOOKEEPER.

Each counter creates a ZNode:

 +----O /flink/checkpoint-counter/<job-id> 1 [persistent]
 .
 .
 .
 +----O /flink/checkpoint-counter/<job-id> N [persistent]
 

The checkpoints IDs are required to be ascending (per job). In order to guarantee this in case of job manager failures we use ZooKeeper to have a shared counter across job manager instances.

Constructor Summary

Constructors

Constructor and Description
ZooKeeperCheckpointIDCounter(org.apache.curator.framework.CuratorFramework client, String counterPath) Creates a ZooKeeperCheckpointIDCounter instance.

Method Summary

Modifier and Type	Method and Description
long	getAndIncrement() Atomically increments the current checkpoint ID.
void	setCount(long newId) Sets the current checkpoint ID.
void	shutdown() Shuts the CheckpointIDCounter service down and frees all created resources.
void	start() Starts the CheckpointIDCounter service.
void	suspend() Suspends the counter.

Methods inherited from class java.lang.Object

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

Constructor Detail

ZooKeeperCheckpointIDCounter

public ZooKeeperCheckpointIDCounter(org.apache.curator.framework.CuratorFramework client,
                                    String counterPath)
                             throws Exception

Creates a ZooKeeperCheckpointIDCounter instance.

Parameters:

client - Curator ZooKeeper client

counterPath - ZooKeeper path for the counter. It's sufficient to have a path per-job.

Throws:

Exception

Method Detail

start

public void start()
           throws Exception

Description copied from interface: CheckpointIDCounter

Starts the CheckpointIDCounter service.

Specified by:

start in interface CheckpointIDCounter

Throws:

Exception

shutdown

public void shutdown()
              throws Exception

Description copied from interface: CheckpointIDCounter

Shuts the CheckpointIDCounter service down and frees all created resources.

Specified by:

shutdown in interface CheckpointIDCounter

Throws:

Exception

suspend

public void suspend()
             throws Exception

Description copied from interface: CheckpointIDCounter

Suspends the counter.

If the implementation allows recovery, the counter state needs to be kept. Otherwise, this acts as shutdown.

Specified by:

suspend in interface CheckpointIDCounter

Throws:

Exception

getAndIncrement

public long getAndIncrement()
                     throws Exception

Description copied from interface: CheckpointIDCounter

Atomically increments the current checkpoint ID.

Specified by:

getAndIncrement in interface CheckpointIDCounter

Returns:

The previous checkpoint ID

Throws:

Exception

setCount

public void setCount(long newId)
              throws Exception

Description copied from interface: CheckpointIDCounter

Sets the current checkpoint ID.

Specified by:

setCount in interface CheckpointIDCounter

Parameters:

newId - The new ID

Throws:

Exception