[pgpool-general: 3960] Re: accept() scalability issues

Michael Renner michael.renner at amd.co.at
Thu Aug 13 22:18:43 JST 2015

> On 10 Aug 2015, at 11:25, Tatsuo Ishii <ishii at postgresql.org> wrote:
>> So if there’s nothing horribly wrong/out of the ordinary with our setup, I’d pretty much say that with a high number of children fencing around select/accept is dearly needed.
> Ok, here is the experimental patch to serialize select(2) for listen
> fds by using semaphore. Could you please try it out?  The patch is
> against 3.3-stable.

Thank you very much, that worked fine!

In a synthetic test with 1000 children and ~30 connections per second this lowered the amount of context switches from ~38.000/sec to ~1.000/sec.

We’ll test it in production mid next week, will let you know how things go.


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