Package org.apache.cassandra.locator

Class NetworkTopologyStrategy

java.lang.Object

org.apache.cassandra.locator.AbstractReplicationStrategy

org.apache.cassandra.locator.NetworkTopologyStrategy

public class NetworkTopologyStrategy
extends AbstractReplicationStrategy

This Replication Strategy takes a property file that gives the intended replication factor in each datacenter. The sum total of the datacenter replication factor values should be equal to the keyspace replication factor.

So for example, if the keyspace replication factor is 6, the datacenter replication factors could be 3, 2, and 1 - so 3 replicas in one datacenter, 2 in another, and 1 in another - totaling 6.

This class also caches the Endpoints and invalidates the cache if there is a change in the number of tokens.

Field Summary

Fields

Modifier and Type	Field	Description
static java.lang.String	REPLICATION_FACTOR

Fields inherited from class org.apache.cassandra.locator.AbstractReplicationStrategy

configOptions, keyspaceName, snitch

Constructor Summary

Constructors

Constructor	Description
NetworkTopologyStrategy(java.lang.String keyspaceName, TokenMetadata tokenMetadata, IEndpointSnitch snitch, java.util.Map<java.lang.String,java.lang.String> configOptions)

Method Summary

Modifier and Type	Method	Description
EndpointsForRange	calculateNaturalReplicas(Token searchToken, TokenMetadata tokenMetadata)	calculate endpoints in one pass through the tokens by tracking our progress in each DC.
java.util.Set<java.lang.String>	getDatacenters()
ReplicationFactor	getReplicationFactor()	calculate the RF based on strategy_options.
ReplicationFactor	getReplicationFactor(java.lang.String dc)
boolean	hasSameSettings(AbstractReplicationStrategy other)
void	maybeWarnOnOptions(ClientState state)
protected static void	prepareOptions(java.util.Map<java.lang.String,java.lang.String> options, java.util.Map<java.lang.String,java.lang.String> previousOptions)	Support datacenter auto-expansion for CASSANDRA-14303.
java.util.Collection<java.lang.String>	recognizedOptions()
protected void	validateExpectedOptions()
void	validateOptions()

Methods inherited from class org.apache.cassandra.locator.AbstractReplicationStrategy

createReplicationStrategy, getAddressReplicas, getAddressReplicas, getAddressReplicas, getAddressReplicas, getCachedReplicas, getClass, getLocalReplicaFor, getNaturalReplicas, getNaturalReplicasForToken, getPendingAddressRanges, getPendingAddressRanges, getRangeAddresses, getWriteResponseHandler, getWriteResponseHandler, hasTransientReplicas, maybeWarnOnOptions, prepareReplicationStrategyOptions, validateReplicationFactor, validateReplicationStrategy

Methods inherited from class java.lang.Object

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

Field Detail

REPLICATION_FACTOR

public static final java.lang.String REPLICATION_FACTOR

See Also:

Constant Field Values

Constructor Detail

NetworkTopologyStrategy

public NetworkTopologyStrategy(java.lang.String keyspaceName,
                               TokenMetadata tokenMetadata,
                               IEndpointSnitch snitch,
                               java.util.Map<java.lang.String,java.lang.String> configOptions)
                        throws ConfigurationException

Throws:

ConfigurationException

Method Detail

calculateNaturalReplicas

public EndpointsForRange calculateNaturalReplicas(Token searchToken,
                                                  TokenMetadata tokenMetadata)

calculate endpoints in one pass through the tokens by tracking our progress in each DC.

Specified by:

calculateNaturalReplicas in class AbstractReplicationStrategy

Parameters:

searchToken - the token to find the natural endpoints for

tokenMetadata - the token metadata used to find the searchToken, e.g. contains token to endpoint mapping information

Returns:

a copy of the natural endpoints for the given token

See Also:

AbstractReplicationStrategy.getNaturalReplicasForToken(org.apache.cassandra.dht.RingPosition)

getReplicationFactor

public ReplicationFactor getReplicationFactor()

Description copied from class: AbstractReplicationStrategy

calculate the RF based on strategy_options. When overwriting, ensure that this get() is FAST, as this is called often.

Specified by:

getReplicationFactor in class AbstractReplicationStrategy

Returns:

the replication factor

getReplicationFactor

public ReplicationFactor getReplicationFactor(java.lang.String dc)

getDatacenters

public java.util.Set<java.lang.String> getDatacenters()

recognizedOptions

public java.util.Collection<java.lang.String> recognizedOptions()

Overrides:

recognizedOptions in class AbstractReplicationStrategy

prepareOptions

protected static void prepareOptions(java.util.Map<java.lang.String,java.lang.String> options,
                                     java.util.Map<java.lang.String,java.lang.String> previousOptions)

Support datacenter auto-expansion for CASSANDRA-14303. This hook allows us to safely auto-expand the "replication_factor" options out into the known datacenters. It is called via reflection from AbstractReplicationStrategy.prepareReplicationStrategyOptions(Class, Map, Map).

Parameters:

options - The proposed strategy options that will be potentially mutated. If empty, replication_factor will be added either from previousOptions if one exists, or from default_keyspace_rf configuration.

previousOptions - Any previous strategy options in the case of an ALTER statement

validateExpectedOptions

protected void validateExpectedOptions()
                                throws ConfigurationException

Overrides:

validateExpectedOptions in class AbstractReplicationStrategy

Throws:

ConfigurationException

validateOptions

public void validateOptions()
                     throws ConfigurationException

Specified by:

validateOptions in class AbstractReplicationStrategy

Throws:

ConfigurationException

maybeWarnOnOptions

public void maybeWarnOnOptions(ClientState state)

Overrides:

maybeWarnOnOptions in class AbstractReplicationStrategy

hasSameSettings

public boolean hasSameSettings(AbstractReplicationStrategy other)

Overrides:

hasSameSettings in class AbstractReplicationStrategy