Subject: Re: Speeding up JSON + TSQUERY + GIN
To: Jeff Janes <jeff.janes@gmail.com>
References: <2260e4e6-89ae-90dc-278c-81243b3c3510@mail.de>
 <CAMkU=1xyf5ypGew=cgFuczQHqtc59J1CTf2EugF0hwSWu65ZCA@mail.gmail.com>
Cc: "pgsql-performance@postgresql.org" <pgsql-performance@postgresql.org>
From: "Sven R. Kunze" <srkunze@mail.de>
Message-ID: <cffa8be6-4e43-7399-2f7a-5686f65acda2@mail.de>
Date: Tue, 28 Feb 2017 09:27:09 +0100
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On 27.02.2017 19:22, Jeff Janes wrote:
> If by 'permanently', you mean even when you intentionally break 
> things, then no.  You will always be able to intentionally break 
> things.  There is on-going discussion of an auto-prewarm feature.  But 
> that doesn't yet exist; and once it does, a super user will always be 
> able to break it.
>
> Presumably you have a use-case in mind other than intentional sabotage 
> of your caches by root.  But, what is it?  If you reboot the server 
> frequently, maybe you can just throw 'select pg_prewarm...' into an 
> init script?

I didn't express myself well enough. pg_prewarm doesn't help to speed up 
those queries at all.


Looking at these numbers, I wonder why it takes ~5 secs to answer?


Best,
Sven

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    <div class="moz-cite-prefix">On 27.02.2017 19:22, Jeff Janes wrote:<br>
    </div>
    <blockquote
cite="mid:CAMkU=1xyf5ypGew=cgFuczQHqtc59J1CTf2EugF0hwSWu65ZCA@mail.gmail.com"
      type="cite">
      <div dir="ltr">
        <div class="gmail_extra">
          <div class="gmail_quote">If by 'permanently', you mean even
            when you intentionally break things, then no.  You will
            always be able to intentionally break things.  There is
            on-going discussion of an auto-prewarm feature.  But that
            doesn't yet exist; and once it does, a super user will
            always be able to break it.
            <div><br>
            </div>
            <div>Presumably you have a use-case in mind other than
              intentional sabotage of your caches by root.  But, what is
              it?  If you reboot the server frequently, maybe you can
              just throw 'select pg_prewarm...' into an init script?</div>
          </div>
        </div>
      </div>
    </blockquote>
    <br>
    I didn't express myself well enough. pg_prewarm doesn't help to
    speed up those queries at all.<br>
    <br>
    <br>
    Looking at these numbers, I wonder why it takes ~5 secs to answer?<br>
    <br>
    <br>
    Best,<br>
    Sven<br>
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