Add New Load Balancing Policy First_or_random Which Sends Queries to the First Specified Host and If It's Inaccessible Send Queries to Random Hosts of Shard

Why it matters

This feature addresses the need for efficient query routing in cross-replication topology setups by prioritizing a preferred host while maintaining availability through fallback options, improving fault tolerance and query handling.

How to use it

To use this feature, configure the load balancing policy for your cluster by setting the policy to first_or_random in the cluster configuration. Queries will then be sent initially to the first host, and if it is unavailable, they will be routed to random hosts within the shard automatically.