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What is implicit is that the query routing layer would select an instance from which to fetch each partition of a store that the query spans, and then fan out to execute sub-queries against each such partition on the selected instances. However, the current store() API disallows this last step. Callers are only able to query all partitions on the local instance, not one or more specific  partitions partition.

Here's an example of how this is a drawback:

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To fill this gap, this KIP proposes to allow querying a specific partition of a store, while still preserving the ability to query all local partitions. This would also reduce latencies while querying a particular key from an instance, as it will fetch the key only from the specific store partition where it belongs which would be very helpful in instances containing multiple partitions.

Public Interfaces:

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