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Zookeeper >> mail # user >> "Client session timed out, have not heard from server in 143198ms", etc.


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Re: "Client session timed out, have not heard from server in 143198ms", etc.
Anyone?

Best Regards,
Martin Kou
On Mon, Jun 17, 2013 at 12:23 AM, Martin Kou <[EMAIL PROTECTED]> wrote:

> Hi folks,
>
> I've been seeing a lot of client session timed out messages from my server
> logs recently - normally those wouldn't concern me too much since there're
> occasion network outages. However, some of the session time out values are
> abnormally large.
>
> I've been using 40s as the session timeout value for my ZooKeeper
> sessions, and those are confirmed as the negotiated timeouts in the client
> establishment logs as well. However, I'd sometimes see timeout logs stating
> times far longer than 40s - e.g. the one in the title.
>
> Reading from ZooKeeper's source code (I'm using v3.4.4) - it seems there's
> no way the clientCnxnSocket.getIdleRecv() call would cause session time out
> delays of more than 2/3 * sessionTimeout (which is 26.66s in my case). The
> theory I have is.. let's say the ZooKeeper client receives a ping from
> server at time t, and the ClientCnxn.SendThread schedules the next
> doTransport() at t + 26.66s - then the worst thing that could happen is
> there's nothing from the server for 26.66s and so I'd get a session timed
> out mesage with sth like 26667ms - which is quite common during network
> outage. However, sometimes I'm getting these >40s and even >100s time outs
> - and I just can't understand them.
>
> Any clues on how these can happen?
>
> Best Regards,
> Martin Kou
>