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From: "David G. Johnston" <david.g.johnston@gmail.com>
Date: Wed, 4 Mar 2026 09:00:37 -0700
Message-ID: 
 <CAKFQuwaUyN8LeFXmwD2ZiR3M3GZ66kELsTU3JBvGuyS0Ombvww@mail.gmail.com>
Subject: Re: doc: add note that wal_level=logical doesn't set up logical
 replication in itself
To: Euler Taveira <euler@eulerto.com>
Cc: Florents Tselai <florents.tselai@gmail.com>,
 Chao Li <li.evan.chao@gmail.com>,
	Masahiko Sawada <sawada.mshk@gmail.com>,
 pgsql-hackers <pgsql-hackers@lists.postgresql.org>
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On Wed, Mar 4, 2026 at 7:11=E2=80=AFAM Euler Taveira <euler@eulerto.com> wr=
ote:

> >
> > Something like:
> > Note that setting this parameter only enables the required WAL format;
> > it does not configure logical replication by itself.
> >
>
> I don't think such note should be added. If the DBA doesn't know how to
> setup
> logical replication, it should read the Logical Replication chapter.
>
>
Yeah, I don't think this change is directly warranted.  But in trying to
figure out what we can do to improve matters I find that the documentation
here has some room to improve that may indeed reduce confusion and be more
informative than the proposed single line addition.  In particular, now
that we have effective_wal_level it is unclear why people would even be
here changing wal_level in the first place.  The quick start guide to
logical replication is at least partially at fault in that regard.

Since the suggestion made here don't directly apply to the subject of this
email thread, and I've some other suggestions as well, I've started a new
thread here:

https://www.postgresql.org/message-id/CAKFQuwY=3DWLF0OH8JE5T8S=3Daj0LBydiSn=
02fkRE73Sm_KSLRqJQ@mail.gmail.com

David J.

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<div dir=3D"ltr"><div dir=3D"ltr"><div dir=3D"ltr"><div class=3D"gmail_defa=
ult" style=3D"font-family:arial,helvetica,sans-serif"><span style=3D"font-f=
amily:Arial,Helvetica,sans-serif">On Wed, Mar 4, 2026 at 7:11=E2=80=AFAM Eu=
ler Taveira &lt;<a href=3D"mailto:euler@eulerto.com" target=3D"_blank">eule=
r@eulerto.com</a>&gt; wrote:</span></div></div><div class=3D"gmail_quote"><=
blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-l=
eft:1px solid rgb(204,204,204);padding-left:1ex">&gt;<br>
&gt; Something like:<br>
&gt; Note that setting this parameter only enables the required WAL format;=
 <br>
&gt; it does not configure logical replication by itself.<br>
&gt;<br>
<br>
I don&#39;t think such note should be added. If the DBA doesn&#39;t know ho=
w to setup<br>
logical replication, it should read the Logical Replication chapter.<br><br=
></blockquote><div><br></div><div class=3D"gmail_default" style=3D"font-fam=
ily:arial,helvetica,sans-serif">Yeah, I don&#39;t think this change is dire=
ctly warranted.=C2=A0 But in trying to figure out what we can do to improve=
 matters I find that the documentation here has some room to improve that m=
ay indeed reduce confusion and be more informative than the proposed single=
 line addition.=C2=A0 In particular, now that we have effective_wal_level i=
t is unclear why people would even be here changing wal_level in the first =
place.=C2=A0 The quick start guide to logical replication is at least parti=
ally at fault in that regard.</div><div class=3D"gmail_default" style=3D"fo=
nt-family:arial,helvetica,sans-serif"><br></div><div class=3D"gmail_default=
" style=3D"font-family:arial,helvetica,sans-serif">Since the suggestion mad=
e here don&#39;t directly apply to the subject of this email thread, and I&=
#39;ve some other suggestions as well, I&#39;ve started a new thread here:<=
/div><div class=3D"gmail_default" style=3D"font-family:arial,helvetica,sans=
-serif"><br></div><div class=3D"gmail_default" style=3D"font-family:arial,h=
elvetica,sans-serif"><a href=3D"https://www.postgresql.org/message-id/CAKFQ=
uwY=3DWLF0OH8JE5T8S=3Daj0LBydiSn02fkRE73Sm_KSLRqJQ@mail.gmail.com">https://=
www.postgresql.org/message-id/CAKFQuwY=3DWLF0OH8JE5T8S=3Daj0LBydiSn02fkRE73=
Sm_KSLRqJQ@mail.gmail.com</a></div><div class=3D"gmail_default" style=3D"fo=
nt-family:arial,helvetica,sans-serif"><br></div><div class=3D"gmail_default=
" style=3D"font-family:arial,helvetica,sans-serif">David J.</div><div class=
=3D"gmail_default" style=3D"font-family:arial,helvetica,sans-serif"><br></d=
iv></div></div>
</div>

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