Constructor
new DCAwareRoundRobinPolicy(localDcopt, nullable, usedHostsPerRemoteDcopt)
A data-center aware Round-robin load balancing policy.
This policy provides round-robin queries over the node of the local
data center. It also includes in the query plans returned a configurable
number of hosts in the remote data centers, but those are always tried
after the local nodes. In other words, this policy guarantees that no
host in a remote data center will be queried unless no host in the local
data center can be reached.
Parameters:
| Name | Type | Attributes | Description |
|---|---|---|---|
localDc |
String |
<optional> <nullable> |
local datacenter name. |
usedHostsPerRemoteDc |
Number |
<optional> |
the number of host per remote datacenter that the policy will yield \ in a newQueryPlan after the local nodes. |
Extends
- LoadBalancingPolicy
Members
localHostsArray :Array
Type:
- Array
remoteHostsArray :Array
Type:
- Array
Methods
getDistance(host)
Returns the distance depending on the datacenter.
Parameters:
| Name | Type | Description |
|---|---|---|
host |
Host |
init(client, hosts, callback)
Initializes the load balancing policy.
Parameters:
| Name | Type | Description |
|---|---|---|
client |
Client | |
hosts |
HostMap | |
callback |
function |
newQueryPlan(keyspace, queryOptions, callback)
It returns an iterator that yields local nodes first and remotes nodes afterwards.
The amount of remote nodes returned will depend on the usedHostsPerRemoteDc
Parameters:
| Name | Type | Description |
|---|---|---|
keyspace |
String | Name of the keyspace |
queryOptions |
||
callback |
function |