replication

Synopsis

system.graph('graph_name').replication("{'class' : 'NetworkTopologyStrategy', 'dc1' : 3, 'dc2' : 2}")

Description

Create a new graph. The graph_name specified is used to create two DSE database keyspaces, graph_name and graph_name_system, and can only contain alphanumeric and underscore characters.

Examples

Create a new graph and set the graph_name replication configuration using replication()as well as the graph_name_system configuration using systemReplication(). DSE database settings for replication factor are used, either SimpleStrategy for a single datacenter or NetworkTopologyStrategy for multiple datacenters.

The default replication strategy for a multi-datacenter graph is NetworkTopologyStrategy, whereas for a single datacenter, the replication strategy will default to SimpleStrategy. The number of nodes will determine the default replication factor:


number of nodes per datacenter	graph_name replication factor	graph_name_system replication factor
1-3	number of nodes per datacenter	number of nodes per datacenter
greater than 3	3	5

system.graph('food').
  replication("{'class' : 'NetworkTopologyStrategy', 'dc1' : 3, 'dc2' : 2 }").  
  systemReplication("{'class' : 'NetworkTopologyStrategy', 'dc1' : 3, 'dc2' : 2 }").
  ifNotExists().create()

The resulting list:

==>null

The replication settings can be verified using the cqlsh tool, running the CQL command

DESCRIBE keyspace
          food

command:

DESCRIBE KEYSPACE food;

with a result:

CREATE KEYSPACE food WITH replication = {'class': 'NetworkTopologyStrategy', 'dc1: '3', 'dc2' : 2 }  AND durable_writes = true;

In addition to setting the replication factor for the graph_name keyspace, the replication factor for the graph_name_system must also be set.

Restriction: The replication factor and system replication factor cannot be altered once set for the graph_name and graph_name_system keyspaces.