What will happen for long running query -
If coordinator nodes goes down suddenly ?
If any node goes down from which query was fetching data ?
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What happens when the coordinator goes down while servicing a long-running query?
If the coordinator node goes down before the query completes, the driver will never get a response back and will eventually timeout with (for example) a DriverTimeoutException.
If a node that was requested data goes down, what happens next depends on how the cluster is configured. By default if speculative_retry is configured on the table, the coordinator will retry the request with another replica node.
For more information, see How read requests are accomplished. Cheers!
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