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Message-ID: <1f740e0d-f58b-4492-85c4-bbfb330c9f89@postgrespro.ru>
Date: Thu, 19 Jun 2025 23:01:48 +0300
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Subject: Re: does multi host connection string supports login event trigger
 exception
To: legrand legrand <legrand_legrand@hotmail.com>,
 "pgsql-general@lists.postgresql.org" <pgsql-general@lists.postgresql.org>
References: <AS8PR08MB6632193E0D8A5ED714026F84907DA@AS8PR08MB6632.eurprd08.prod.outlook.com>
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From: Pavel Luzanov <p.luzanov@postgrespro.ru>
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Hi, legrand!


On 19.06.2025 22:31, legrand legrand wrote:
> I'm trying to build a login event trigger in conjonction with a multi 
> host connectio string
> to manager instances roles in a logical replication cluster.

According to docs 
<https://www.postgresql.org/docs/current/libpq-connect.html#:~:text=If%20a%20connection%20is%20established%20successfully>:
If a connection is established successfully, but authentication fails, 
the remaining hosts in the list are not tried.

So, I think that this is impossible to use multiple hosts feature of 
libpq with on login trigger to skip some host.

-- 
Pavel Luzanov
Postgres Professional:https://postgrespro.com

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    Hi, legrand!<br>
    <br>
    <br>
    <div class="moz-cite-prefix">On 19.06.2025 22:31, legrand legrand
      wrote:<br>
    </div>
    <blockquote type="cite"
cite="mid:AS8PR08MB6632193E0D8A5ED714026F84907DA@AS8PR08MB6632.eurprd08.prod.outlook.com">
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      <style type="text/css" style="display:none;">P {margin-top:0;margin-bottom:0;}</style>
      <div class="elementToProof"
style="font-family: &quot;Calibri&quot;, &quot;Helvetica&quot;, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
        I'm trying to build a login event trigger in conjonction with a
        multi host connectio string</div>
      <div class="elementToProof"
style="font-family: &quot;Calibri&quot;, &quot;Helvetica&quot;, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
        to manager instances roles in a logical replication cluster.</div>
    </blockquote>
    <br>
    According to <a
href="https://www.postgresql.org/docs/current/libpq-connect.html#:~:text=If%20a%20connection%20is%20established%20successfully">docs</a>:<br>
    If a connection is established successfully, but authentication
    fails, the remaining hosts in the list are not tried.<br>
    <br>
    So, I think that this is impossible to use multiple hosts feature of
    libpq with on login trigger to skip some host. <br>
    <pre class="moz-signature" cols="72">-- 
Pavel Luzanov
Postgres Professional: <a class="moz-txt-link-freetext" href="https://postgrespro.com">https://postgrespro.com</a></pre>
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