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Status

Current state: ["Under Discussion"]

Discussion thread: here [Change the link from the KIP proposal email archive to your own email thread]

JIRA: here [Change the link from KAFKA-1 to your own ticket]

Please keep the discussion on the mailing list rather than commenting on the wiki (wiki discussions get unwieldy fast).

Motivation

In all of the current Kafka clients, we have retry mechanisms with a fixed backoff to handle transient connection issues with the brokers. However with a small backoff (currently it defaults to 100 ms), we could send tens of requests per second to the broker, and if the connection issue is prolonged, this could mean quite a bit of pressure on the brokers.

To reduce this pressure, it would be useful to support an exponentially increasing backoff policy for all Kafka clients, similar to the configuration introduced in KIP-144 for exponentially increasing backoffs for broker reconnect attempts.

Public Interfaces

Introduce a new common client configuration for clients called retry.backoff.max.ms that is defined as:

The maximum amount of time in milliseconds to wait when retrying a request to the broker that has repeatedly failed. If provided, the backoff per client will increase exponentially for each failed request, up to this maximum.

This config would default to 1000 ms if retry.backoff.ms is not set explicitly. Otherwise, it will default to the same value as retry.backoff.ms. The formula to calculate the backoff is as follows (where retry.backoff.ms starts out with 100 ms, which is the default):

retry.backoff.ms * 2**(failures - 1)

This will keep increasing until it hits the retry.backoff.max.ms value.

Proposed Changes

Describe the new thing you want to do in appropriate detail. This may be fairly extensive and have large subsections of its own. Or it may be a few sentences. Use judgement based on the scope of the change.

Compatibility, Deprecation, and Migration Plan

• What impact (if any) will there be on existing users?
• If we are changing behavior how will we phase out the older behavior?
• If we need special migration tools, describe them here.
• When will we remove the existing behavior?

Rejected Alternatives

If there are alternative ways of accomplishing the same thing, what were they? The purpose of this section is to motivate why the design is the way it is and not some other way.