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Re: Very poor read performance, query independent

From:	Claudio Freire <klaussfreire(at)gmail(dot)com>
To:	Charles Nadeau <charles(dot)nadeau(at)gmail(dot)com>
Cc:	Igor Neyman <ineyman(at)perceptron(dot)com>, Jeff Janes <jeff(dot)janes(at)gmail(dot)com>, "pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org>
Subject:	Re: Very poor read performance, query independent
Date:	2017-07-18 16:01:29
Message-ID:	CAGTBQpYUAKhrKYiTm3LNVAwV0trk9RCxZT-CDzUZsUFnME0emg@mail.gmail.com
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On Tue, Jul 18, 2017 at 6:20 AM, Charles Nadeau
<charles(dot)nadeau(at)gmail(dot)com> wrote:
> Claudio,
>
> At one moment
> during the query, there is a write storm to the swap drive (a bit like this
> case:
> https://www.postgresql.org/message-id/AANLkTi%3Diw4fC2RgTxhw0aGpyXANhOT%3DXBnjLU1_v6PdA%40mail.gmail.com).
> I can hardly explain it as there is plenty of memory on this server.

That sounds a lot like NUMA zone_reclaim issues:

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