Re: PostgresSQL 9.5.21 very slow to connect and perform basic queries

From: bruno da silva <brunogiovs(at)gmail(dot)com>
To: Justin Pryzby <pryzby(at)telsasoft(dot)com>
Cc: pgsql-performance(at)lists(dot)postgresql(dot)org
Subject: Re: PostgresSQL 9.5.21 very slow to connect and perform basic queries
Date: 2022-07-21 20:32:08
Message-ID: CAB+Nuk_qs4Y859Q=AsJyjVcQam9E98+bsL9p_-JTJgoWAM-Juw@mail.gmail.com
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Thanks, I will check it out.

On Thu, Jul 21, 2022 at 4:21 PM Justin Pryzby <pryzby(at)telsasoft(dot)com> wrote:

> On Thu, Jul 21, 2022 at 03:59:30PM -0400, bruno da silva wrote:
> > OS/version: CentOS release 6.9 (Final)
>
> How are these set ?
>
> tail /sys/kernel/mm/ksm/run
> /sys/kernel/mm/transparent_hugepage/{defrag,enabled,khugepaged/defrag}
> /proc/sys/vm/zone_reclaim_mode
>
> I suspect you may be suffering from issues with transparent huge pages.
>
> I suggest to disable KSM and THP, or upgrade to a newer OS.
>
> I've written before about these:
> https://www.postgresql.org/message-id/20170524155855.GH31097@telsasoft.com
> https://www.postgresql.org/message-id/20190625162338.GF18602@telsasoft.com
> https://www.postgresql.org/message-id/20170718180152.GE17566@telsasoft.com
> https://www.postgresql.org/message-id/20191004060300.GA11241@telsasoft.com
> https://www.postgresql.org/message-id/20200413144254.GS2228@telsasoft.com
> https://www.postgresql.org/message-id/20220329182453.GA28503@telsasoft.com
>
> On Thu, Jul 21, 2022 at 04:01:10PM -0400, bruno da silva wrote:
> > The issue started a month ago.
>
> Ok .. but how long has the DB been running under this environment ?
>
> --
> Justin
>

--
Bruno da Silva

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