[jira] [Commented] (KAFKA-6028) Improve the quota throttle communication.

["ASF GitHub Bot (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/KAFKA-6028?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16427730#comment-16427730 ] 

ASF GitHub Bot commented on KAFKA-6028:
---------------------------------------

jonlee2 opened a new pull request #4830: KAFKA-6028: Improve the quota throttle communication (KIP-219)
URL: https://github.com/apache/kafka/pull/4830
 
 
   This implements KIP-219, where a broker return a response with throttle time on quota violation immediately after processing the corresponding request. After the response is sent out, the broker will keep the channel muted until the throttle time is over. Also, on receiving a response with throttle time, client will also block outgoing communication to the broker for the specified throttle time.
   
   In the original KIP, it was stated that "In order to let the clients know whether the received response is already throttled or not, we will need to bump up all the related request version." However, after further discussion with @lindong28 and @becketqin, it was decided to bump up the protocol version of ApiVersionsRequest/Response only, which should be sufficient to detect the throttling behavior of the brokers that each client communicate with. 
   
   Initial review was done by @lindong28. 
   
   ### Committer Checklist (excluded from commit message)
   - [ ] Verify design and implementation 
   - [ ] Verify test coverage and CI build status
   - [ ] Verify documentation (including upgrade notes)
   

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> Improve the quota throttle communication.
> -----------------------------------------
>
>                 Key: KAFKA-6028
>                 URL: https://issues.apache.org/jira/browse/KAFKA-6028
>             Project: Kafka
>          Issue Type: Improvement
>          Components: clients, core
>    Affects Versions: 1.0.0
>            Reporter: Jiangjie Qin
>            Assignee: Jiangjie Qin
>            Priority: Major
>             Fix For: 1.2.0
>
>
> Currently if a client is throttled duet to quota violation, the broker will only send back a response to the clients after the throttle time has passed. In this case, the clients don't know how long the response will be throttled and might hit request timeout before the response is returned. As a result the clients will retry sending a request and results a even longer throttle time.
> The above scenario could happen when a large clients group sending records to the brokers. We saw this when a MapReduce job pushes data to the Kafka cluster.
> To improve this, the broker can return the response with throttle time immediately after processing the requests. After that, the broker will mute the channel for this client. A correct client implementation should back off for that long before sending the next request. If the client ignored the throttle time and send the next request immediately, the channel will be muted and the request won't be processed until the throttle time has passed.
> A KIP will follow with more details.



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