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ILoadBalancingPolicy Interface
The policy that decides which Cassandra hosts to contact for each new query. For efficiency purposes, the policy is expected to exclude down hosts from query plans.

Namespace: Cassandra
Assembly: Cassandra (in Cassandra.dll) Version: 3.2.0
Syntax
C#
public interface ILoadBalancingPolicy

The ILoadBalancingPolicy type exposes the following members.

Methods
  NameDescription
Public methodDistance
Returns the distance assigned by this policy to the provided host.

The distance of an host influence how much connections are kept to the node (see HostDistance). A policy should assign a * LOCAL distance to nodes that are susceptible to be returned first by newQueryPlan and it is useless for newQueryPlan to return hosts to which it assigns an IGNORED distance.

The host distance is primarily used to prevent keeping too many connections to host in remote datacenters when the policy itself always picks host in the local datacenter first.

Public methodInitialize
Initialize this load balancing policy.

Note that the driver guarantees that it will call this method exactly once per policy object and will do so before any call to another of the methods of the policy.

Public methodNewQueryPlan
Returns the hosts to use for a new query.

Each new query will call this method. The first host in the result will then be used to perform the query. In the event of a connection problem (the queried host is down or appear to be so), the next host will be used. If all hosts of the returned Iterator are down, the query will fail.

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