Reply-To: jesper.pedersen@redhat.com
Subject: Re: pg_receivewal documentation
To: Michael Paquier <michael@paquier.xyz>,
 Laurenz Albe <laurenz.albe@cybertec.at>
Cc: Alvaro Herrera <alvherre@2ndquadrant.com>,
 PostgreSQL-development <pgsql-hackers@postgresql.org>
References: <20190710142421.GA28387@alvherre.pgsql>
 <54779de5-f922-c0cf-629d-b582eded7265@redhat.com>
 <20190716050555.GA1439@paquier.xyz>
 <ebed4b9043b222d486ea3f0e44e7dcd242a80781.camel@cybertec.at>
 <65c3ecdf-8995-34cb-83c4-50068877e632@redhat.com>
 <20190717013835.GA2130@paquier.xyz>
 <44e51f9f60abb872854879c91da0ed3b67a6ba95.camel@cybertec.at>
 <20190717080424.GB20614@paquier.xyz>
From: Jesper Pedersen <jesper.pedersen@redhat.com>
Organization: Red Hat
Message-ID: <7eaf748c-3f40-c994-0eb3-7d87709588d0@redhat.com>
Date: Wed, 17 Jul 2019 13:59:55 -0400
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Hi,

On 7/17/19 4:04 AM, Michael Paquier wrote:
>> How about adding "or priority-based" after "quorum-based"?
> 
> I would be fine with that for the first part.  I am not sure of what a
> good formulation would be for the second part of the sentence.  Now it
> only refers to quorum, but with priority sets that does not apply.
> And I am not sure what "won't count towards the quorum" actually
> means.

Maybe something like the attached ?  Although it doesn't help we need to 
include <literal>on</literal> as well...

Best regards,
  Jesper


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From f1ec4f9e715c798440288bb4e5c97100bf4efacc Mon Sep 17 00:00:00 2001
From: jesperpedersen <jesper.pedersen@redhat.com>
Date: Tue, 9 Jul 2019 13:14:25 -0400
Subject: [PATCH] Highlight that pg_receivewal doesn't apply WAL, and as such
 synchronous-commit needs to be remote_write or lower.
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Authors: Álvaro Herrera, Laurenz Albe and Jesper Pedersen
Review-by: Álvaro Herrera, Laurenz Albe and Jesper Pedersen
---
 doc/src/sgml/ref/pg_receivewal.sgml | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/doc/src/sgml/ref/pg_receivewal.sgml b/doc/src/sgml/ref/pg_receivewal.sgml
index 0506120c00..254315c6bf 100644
--- a/doc/src/sgml/ref/pg_receivewal.sgml
+++ b/doc/src/sgml/ref/pg_receivewal.sgml
@@ -207,6 +207,19 @@ PostgreSQL documentation
         server as a synchronous standby, to ensure that timely feedback is
         sent to the server.
        </para>
+
+       <para>
+        Note that while WAL will be flushed with this setting,
+        <application>pg_receivewal</application> never applies it, so
+        <xref linkend="guc-synchronous-commit"/> must not be set to
+        <literal>remote_apply</literal> or <literal>on</literal>
+        if <application>pg_receivewal</application> is the only synchronous standby.
+        Similarly, if <application>pg_receivewal</application> is part of a
+        priority-based synchronous replication setup (<literal>FIRST</literal>),
+        or a quorum-based setup (<literal>ANY</literal>) it won't count towards
+        the policy specified if <xref linkend="guc-synchronous-commit"/> is
+        set to <literal>remote_apply</literal> or <literal>on</literal>.
+       </para>
       </listitem>
      </varlistentry>
 
-- 
2.21.0


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