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From Vitalii Tymchyshyn <...@tym.im>
Subject Re: ZooKeeper ping requests Unnecessarily go though request processor chain
Date Mon, 03 Oct 2016 12:26:41 GMT
Hi.

I think this would break ordering guarantie, would not it?
Also ping is supposed to test health and I am not sure why do you want to
skip testing part of the flow? Does it incur high load?
What would happen if disk would stall for a minute?

Best regards, Vitalii Tymchyshyn

Пн, 3 жовт. 2016 05:11 користувач Mohammad arshad <
mohammad.arshad@huawei.com> пише:

> Hi All
> ZooKeeper clients send ping request(heartbeat) to ZooKeeper server to keep
> its session alive. These ping requests do nothing but touch its session on
> the server.
>
> If client is connected to a follower then the ping request is processed in
> sequence of ServerCnxn --> ZooKeeperServer --> FollowerRequestProcessor -->
> CommitProcessor --> FinalRequestProcessor. The ping request will wait in
> CommitProcessor for previous request completion. This wait for ping request
> is unnecessary. I think it offers no benefit.
>
> is ping request doing more than touching its session? I think it is only
> touching its session, not doing anything else.
> If this is the case we should process the ping request differently from
> the other requests. It should be  treated as system request and should be
> processed with higher priority. May be we can process in the sequence of
> ServerCnxn --> ZooKeeperServer --> PingRequestProcessor
>
> Any thought?
>
> Thanks
> -Arshad
>
>

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