Package org.apache.cassandra.config

Enum Config.BatchlogEndpointStrategy

java.lang.Object

java.lang.Enum<Config.BatchlogEndpointStrategy>

org.apache.cassandra.config.Config.BatchlogEndpointStrategy

All Implemented Interfaces:

java.io.Serializable, java.lang.Comparable<Config.BatchlogEndpointStrategy>

Enclosing class:

Config

public static enum Config.BatchlogEndpointStrategy
extends java.lang.Enum<Config.BatchlogEndpointStrategy>

Enum Constant Summary

Enum Constants

Enum Constant	Description
dynamic	Strategy using Config.dynamic_snitch (DynamicEndpointSnitch) to select batchlog storage endpoints.
dynamic_remote	Strategy using Config.dynamic_snitch (DynamicEndpointSnitch) to select batchlog storage endpoints.
prefer_local	Random, except that one of the replications will go to the local rack.
random_remote	Old, conventional strategy to select batchlog storage endpoints.

Field Summary

Fields

Modifier and Type	Field	Description
boolean	preferLocalRack	If true, one of the selected nodes will come from the local rack.
boolean	useDynamicSnitchScores	If true, dynamic snitch response times will be used to select more responsive nodes to write the batchlog to.

Method Summary

Modifier and Type	Method	Description
static Config.BatchlogEndpointStrategy	valueOf(java.lang.String name)	Returns the enum constant of this type with the specified name.
static Config.BatchlogEndpointStrategy[]	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

random_remote

public static final Config.BatchlogEndpointStrategy random_remote

Old, conventional strategy to select batchlog storage endpoints. Purely random, prevents the local rack, if possible.

prefer_local

public static final Config.BatchlogEndpointStrategy prefer_local

Random, except that one of the replications will go to the local rack. Which means this strategy offers lower availability guarantees than random_remote or dynamic_remote.

dynamic_remote

public static final Config.BatchlogEndpointStrategy dynamic_remote

Strategy using Config.dynamic_snitch (DynamicEndpointSnitch) to select batchlog storage endpoints. Prevents the local rack, if possible. This strategy offers the same availability guarantees as random_remote but selects the fastest endpoints according to the DynamicEndpointSnitch. Hint: DynamicEndpointSnitch tracks reads and not writes - i.e. write-only (or mostly-write) workloads might not benefit from this strategy. Note: this strategy will fall back to random_remote, if Config.dynamic_snitch is not enabled.

dynamic

public static final Config.BatchlogEndpointStrategy dynamic

Strategy using Config.dynamic_snitch (DynamicEndpointSnitch) to select batchlog storage endpoints. Does not prevent the local rack. Since the local rack is not excluded, this strategy offers lower availability guarantees than random_remote or dynamic_remote. Hint: DynamicEndpointSnitch tracks reads and not writes - i.e. write-only (or mostly-write) workloads might not benefit from this strategy. Note: this strategy will fall back to random_remote, if Config.dynamic_snitch is not enabled.

Field Detail

useDynamicSnitchScores

public final boolean useDynamicSnitchScores

If true, dynamic snitch response times will be used to select more responsive nodes to write the batchlog to. If false, nodes will be randomly selected.

preferLocalRack

public final boolean preferLocalRack

If true, one of the selected nodes will come from the local rack. If false, the local rack will not be used except as a last resort with no other racks available.

Method Detail

values

public static Config.BatchlogEndpointStrategy[] 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 (Config.BatchlogEndpointStrategy c : Config.BatchlogEndpointStrategy.values())
    System.out.println(c);

Returns:

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

valueOf

public static Config.BatchlogEndpointStrategy 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