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From: Ron Johnson <ronljohnsonjr@gmail.com>
Date: Thu, 27 Jun 2024 11:43:47 -0400
Message-ID: <CANzqJaDP92SxE+y1VpVr1TXfKhJ-DKwTOtNxetwnyL0qs2eWxg@mail.gmail.com>
Subject: Re: A way to optimize sql about the last temporary-related row
To: pgsql-general <pgsql-general@postgresql.org>
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On Thu, Jun 27, 2024 at 11:33=E2=80=AFAM agharta82@gmail.com <agharta82@gma=
il.com>
wrote:

> Hi,
>
> You are right. Too quickly copy-paste on my part :-)
>
> I take this opportunity to add a NOT insignificant detail.
>
> Before executing the select query I clear the cache:
>
> systemctl stop postgresql-16 && sync && echo 3 > /proc/sys/vm/drop_caches
> &&  systemctl start postgresql-16
>
> I need to get a performance result even if data is not in cache.
>

In addition to David's suggestion, consider the pg_prewarm extension:
https://www.postgresql.org/docs/current/pgprewarm.html

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<div dir=3D"ltr"><div dir=3D"ltr">On Thu, Jun 27, 2024 at 11:33=E2=80=AFAM =
<a href=3D"mailto:agharta82@gmail.com">agharta82@gmail.com</a> &lt;<a href=
=3D"mailto:agharta82@gmail.com">agharta82@gmail.com</a>&gt; wrote:<br></div=
><div class=3D"gmail_quote"><blockquote class=3D"gmail_quote" style=3D"marg=
in:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1e=
x"><u></u>

 =20
   =20
 =20
  <div>
    <p>Hi,</p>
    <p>You are right. Too quickly copy-paste on my part :-)</p>
    <p>I take this opportunity to add a NOT insignificant detail.</p>
    <p>Before executing the select query I clear the cache:<br>
    </p>
    <p>systemctl stop postgresql-16 &amp;&amp; sync &amp;&amp; echo 3
      &gt; /proc/sys/vm/drop_caches=C2=A0 &amp;&amp;=C2=A0 systemctl start
      postgresql-16</p>
    <p>I need to get a performance result even if data is not in cache.</p>=
</div></blockquote><div><br></div><div>In addition to David&#39;s suggestio=
n, consider the pg_prewarm extension:=C2=A0<a href=3D"https://www.postgresq=
l.org/docs/current/pgprewarm.html">https://www.postgresql.org/docs/current/=
pgprewarm.html</a></div><div>=C2=A0</div></div></div>

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