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This config must be set to at least one1.
The default value is set to 10. We ran experiments showing the impact of zookeeper.max.in.flight.requests
on completion times for various ZooKeeper-intensive controller protocols. The default was chosen to be the smallest number beyond which the experiment results have found diminishing returns.
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- Set the default value to be unbounded (Integer.MAX_VALUE), effectively stating that no such limit be applied and to pipeline as aggressively as possible. This was rejected because a config should not default to removing control over the system.
- Set the default value to one1, effectively disabling pipelining and maintaining Kafka's synchronous requests to ZooKeeper. This was rejected because we want users to see the benefits of pipelining.