Full ERROR Message Example

Encountered error while trying to preprocess the message {}, in command {}, replica plan {}

What does this ERROR message mean?

When a read response message is received from a replica, the coordinator adds it to an accumulator of responses, which it will later resolve based on timestamps and return the latest data to the client. This error means that more than the expected number of responses were received.

Why does this ERROR occur?

The accumulator is initialized with a predefined size based on the number of potential candidate replicas that the coordinator could send a read request to. If the response resolver attempts to add more responses to the accumulator than it was initialized with, the accumulator will throw an IllegalStateException which triggers this error message. This error could potentially occur if more endpoints responded to a read request than the coordinator sent requests to. This should never happen, and has never been observed in practice.

How do you fix this ERROR?

Since this error is very unlikely to happen and has not been seen before, fixing it would require a detailed investigation to determine where the extra response came from and why it was generated. Please contact DataStax support if you encounter it.