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From: Ron Johnson <ronljohnsonjr@gmail.com>
Date: Sun, 19 Apr 2026 21:31:43 -0400
Message-ID: <CANzqJaBRRq5T-3VJc5fzGSOotAW8eXg1cvh0XwoRc4akO+mamg@mail.gmail.com>
Subject: Re: List of encodings
To: "pgsql-generallists.postgresql.org" <pgsql-general@lists.postgresql.org>
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On Sun, Apr 19, 2026 at 9:13=E2=80=AFPM Igor Korot <ikorot01@gmail.com> wro=
te:

> [snip]
> >
> > In your setup all the installed encoding conversion functions are also
> > the default for those conversions. It is possible to create/install a
> > conversion function that is not the default.
>
> So, let's say I chose "BIG5"".
>
> As stated the table contains:
>
>  big5_to_utf8                   | BIG5           | t
>  big5_to_euc_tw                 | BIG5           | t
>  big5_to_mic                    | BIG5           | t
>
> Since all 3 are default character sets, which one would be chosen?
> (in the context of CREATE DATABASE)
>

Does CREATE DATABASE *convert text*?  (I think you might be
misunderstanding the purpose of the pg_conversion table.)

Wouldn't it only *convert* text when a client is inserting text of encoding
X into a table with encoding Y?

ISTM that pg_conversion says whether PG knows how to convert from X to Y,
not the encoding scheme you defined when creating the db.

--=20
Death to <Redacted>, and butter sauce.
Don't boil me, I'm still alive.
<Redacted> lobster!

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<div dir=3D"ltr"><div dir=3D"ltr"><br></div><br><div class=3D"gmail_quote g=
mail_quote_container"><div dir=3D"ltr" class=3D"gmail_attr">On Sun, Apr 19,=
 2026 at 9:13=E2=80=AFPM Igor Korot &lt;<a href=3D"mailto:ikorot01@gmail.co=
m">ikorot01@gmail.com</a>&gt; wrote:<br></div><blockquote class=3D"gmail_qu=
ote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,20=
4);padding-left:1ex">[snip]<br>
&gt;<br>
&gt; In your setup all the installed encoding conversion functions are also=
<br>
&gt; the default for those conversions. It is possible to create/install a<=
br>
&gt; conversion function that is not the default.<br>
<br>
So, let&#39;s say I chose &quot;BIG5&quot;&quot;.<br>
<br>
As stated the table contains:<br>
<br>
=C2=A0big5_to_utf8=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =
=C2=A0 =C2=A0| BIG5=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0| t<br>
=C2=A0big5_to_euc_tw=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0=
 =C2=A0| BIG5=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0| t<br>
=C2=A0big5_to_mic=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =
=C2=A0 =C2=A0 | BIG5=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0| t<br>
<br>
Since all 3 are default character sets, which one would be chosen?<br>
(in the context of CREATE DATABASE)<br></blockquote><div></div></div><div><=
br></div><div>Does CREATE DATABASE <b>convert text</b>?=C2=A0 (I think you =
might be misunderstanding the purpose of the pg_conversion table.)</div><di=
v><br></div><div>Wouldn&#39;t it only <i>convert</i>=C2=A0text when a clien=
t is inserting text of encoding X into a table with encoding Y?</div><div><=
br></div><div>ISTM that pg_conversion says whether PG knows how to convert =
from X to Y, not the encoding scheme you defined when creating the db.</div=
><div><br></div><span class=3D"gmail_signature_prefix">-- </span><br><div d=
ir=3D"ltr" class=3D"gmail_signature"><div dir=3D"ltr">Death to &lt;Redacted=
&gt;, and butter sauce.<div>Don&#39;t boil me, I&#39;m still alive.<br><div=
><div>&lt;Redacted&gt; lobster!</div></div></div></div></div></div>

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