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.
If used with a single data center, this policy is equivalent to the {@code LoadBalancingPolicy.RoundRobin} policy, but its DC awarenessincurs a slight overhead so the {@code LoadBalancingPolicy.RoundRobin}policy could be preferred to this policy in that case.
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