com.sleepycat.je

Enum Durability.ReplicaAckPolicy

java.lang.Object

java.lang.Enum<Durability.ReplicaAckPolicy>

com.sleepycat.je.Durability.ReplicaAckPolicy

All Implemented Interfaces:

java.io.Serializable, java.lang.Comparable<Durability.ReplicaAckPolicy>

Enclosing class:

Durability

public static enum Durability.ReplicaAckPolicy
extends java.lang.Enum<Durability.ReplicaAckPolicy>

A replicated environment makes it possible to increase an application's transaction commit guarantees by committing changes to its replicas on the network. ReplicaAckPolicy defines the policy for how such network commits are handled.

The choice of a ReplicaAckPolicy must be consistent across all the replicas in a replication group, to ensure that the policy is consistently enforced in the event of an election.

Note that SECONDARY nodes are not included in the set of replicas that must acknowledge transaction commits.

Enum Constant Summary

Enum Constants

Enum Constant and Description
ALL All ELECTABLE replicas must acknowledge that they have committed the transaction.
NONE No transaction commit acknowledgments are required and the master will never wait for replica acknowledgments.
SIMPLE_MAJORITY A simple majority of ELECTABLE replicas must acknowledge that they have committed the transaction.

Method Summary

Modifier and Type	Method and Description
int	minAckNodes(int groupSize) Returns the minimum number of ELECTABLE replicas required to implement the ReplicaAckPolicy for a given replication group size.
static Durability.ReplicaAckPolicy	valueOf(java.lang.String name) Returns the enum constant of this type with the specified name.
static Durability.ReplicaAckPolicy[]	values() Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

ALL

public static final Durability.ReplicaAckPolicy ALL

All ELECTABLE replicas must acknowledge that they have committed the transaction. This policy should be selected only if your replication group has a small number of ELECTABLE replicas, and those replicas are on extremely reliable networks and servers.

NONE

public static final Durability.ReplicaAckPolicy NONE

No transaction commit acknowledgments are required and the master will never wait for replica acknowledgments. In this case, transaction durability is determined entirely by the type of commit that is being performed on the master.

SIMPLE_MAJORITY

public static final Durability.ReplicaAckPolicy SIMPLE_MAJORITY

A simple majority of ELECTABLE replicas must acknowledge that they have committed the transaction. This acknowledgment policy, in conjunction with an election policy which requires at least a simple majority, ensures that the changes made by the transaction remains durable if a new election is held.

This is the default.

Method Detail

values

public static Durability.ReplicaAckPolicy[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (Durability.ReplicaAckPolicy c : Durability.ReplicaAckPolicy.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static Durability.ReplicaAckPolicy valueOf(java.lang.String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

java.lang.IllegalArgumentException - if this enum type has no constant with the specified name

java.lang.NullPointerException - if the argument is null

minAckNodes

public int minAckNodes(int groupSize)

Returns the minimum number of ELECTABLE replicas required to implement the ReplicaAckPolicy for a given replication group size.

Parameters:

groupSize - the number of ELECTABLE replicas in the replication group

Returns:

the number of ELECTABLE replicas needed