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From Pid <>
Subject Re: Handling requests when under load - ACCEPT and RST vs non-ACCEPT
Date Sun, 11 Nov 2012 14:14:48 GMT
On 10/11/2012 04:52, Asankha C. Perera wrote:
> Hi Chris
>> ....processing 1 connection through completion
>> (there are 99 others still running), re-binding, accepting a single
>> connection into the application plus 100 others into the backlog, then
>> choking again and dropping 100 connections, then processing another
>> single connection. That's a huge waste of time unbinding and
>> re-binding to the port, killing the backlog over and over again... and
>> all for 1-connection-at-a-time pumping. Insanity.
> I'm sorry but you've misunderstood what I was saying. Yes the example I
> used showed it for one connection to make it easier to understand what I
> was proposing. But in reality you would not stop and start at each
> connection. Remember the two thresholds I was talking about? You could
> stop listening at 4K connections, and start listening again when the
> connections drops to say 3K - and these could be user specified
> parameters based on the deployment.
> HTTP keep-alive from a load balancer in front would work extremely well
> under these conditions as established TCP connections are re-used. Any
> production grade load balancer could immediately fail-over only the
> failing requests to another Tomcat when one is under too much load - and
> this would work for even non-idempotent services.

If there's an LB in front, it should be protecting the Tomcat instance
from an excessive number of connections, no?


>> You want to add all this extra complexity to the code and, IMO, shitty
>> handling of your incoming connections just so you can say "well,
>> you're getting 'connection refused' instead of hanging... isn't that
>> better?". I assert that it is *not* better. Clients can set TCP
>> handshake timeouts and survive. Your server will perform much better
>> without all this foolishness.
> If you can, try to understand what I said better.. Its ok to not accept
> this proposal and/or not understand it..
> regards
> asankha



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