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Mon, 20 Apr 2026 19:55:18 -0700 (PDT) MIME-Version: 1.0 References: <71cd4015-9002-4173-bd9a-075f7afb3c20@aklaver.com> <5f263a8a-9c30-4118-b410-6e25eafde156@aklaver.com> In-Reply-To: From: Ron Johnson Date: Mon, 20 Apr 2026 22:55:07 -0400 X-Gm-Features: AQROBzC3d3jY8T4Muax_wRVYJEs9RhppgW8Vp2VPK8GsFbSbnnQUzU0SHctMwlU Message-ID: Subject: Re: List of encodings To: Igor Korot Cc: "pgsql-generallists.postgresql.org" Content-Type: multipart/alternative; boundary="000000000000a37642064fef8b1c" List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Archived-At: Precedence: bulk --000000000000a37642064fef8b1c Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Igor, pg_*conversion* is for when you *convert* text. Why does it matter if you never convert text? On Mon, Apr 20, 2026 at 10:47=E2=80=AFPM Igor Korot wr= ote: > My understanding is that if I have 3 "BIG5" encodings, only one can be > a default. > > And if you want you can choose the other 2, but selecting "BIG5" will > make only one > to be selected by default. > That is why it is called "default" ;-) > > Thank you. > > On Mon, Apr 20, 2026 at 7:42=E2=80=AFPM Igor Korot w= rote: > > > > Hi, ALL, > > > > > > On Sun, Apr 19, 2026 at 8:32=E2=80=AFPM Ron Johnson > wrote: > > > > > > > > > > > > On Sun, Apr 19, 2026 at 9:13=E2=80=AFPM Igor Korot wrote: > > >> > > >> [snip] > > >> > > > >> > In your setup all the installed encoding conversion functions are > also > > >> > the default for those conversions. It is possible to create/instal= l > 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.) > > > > No it does not. > > > > But it has an option that can be chosen and supplied to the command... > > > > So when I write "CREATE DATABASE mydb ECODING =3D BIG5", what will happ= en? > > > > Moreover, I'm curious - if I chose "BIG5", there are only number of > > available collate/ctype pairs. > > How do I choose which one to present to the user. > > Because there is not one default "BIG5" - there are 3 default "BIG5"s. > > > > Thank you. > > > > > > > > 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 t= o > Y, not the encoding scheme you defined when creating the db. > > > > > > -- > > > Death to , and butter sauce. > > > Don't boil me, I'm still alive. > > > lobster! > --=20 Death to , and butter sauce. Don't boil me, I'm still alive. lobster! --000000000000a37642064fef8b1c Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Igor,

pg_conversion= =C2=A0is for when you convert=C2=A0text.=C2=A0 Why does it matte= r if you never convert text?

On Mon, Apr 20, 202= 6 at 10:47=E2=80=AFPM Igor Korot <= ikorot01@gmail.com> wrote:
My understanding is that if I have 3 "BIG5" enc= odings, only one can be
a default.

And if you want you can choose the other 2, but selecting "BIG5" = will
make only one
to be selected by default.
That is why it is called "default" ;-)

Thank you.

On Mon, Apr 20, 2026 at 7:42=E2=80=AFPM Igor Korot <ikorot01@gmail.com> wrote:
>
> Hi, ALL,
>
>
> On Sun, Apr 19, 2026 at 8:32=E2=80=AFPM Ron Johnson <ronljohnsonjr@gmail.com&= gt; wrote:
> >
> >
> >
> > On Sun, Apr 19, 2026 at 9:13=E2=80=AFPM Igor Korot <ikorot01@gmail.com> wr= ote:
> >>
> >> [snip]
> >> >
> >> > In your setup all the installed encoding conversion func= tions are also
> >> > the default for those conversions. It is possible to cre= ate/install a
> >> > conversion function that is not the default.
> >>
> >> So, let's say I chose "BIG5"".
> >>
> >> As stated the table contains:
> >>
> >>=C2=A0 big5_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
> >>=C2=A0 big5_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
> >>=C2=A0 big5_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
> >>
> >> Since all 3 are default character sets, which one would be ch= osen?
> >> (in the context of CREATE DATABASE)
> >
> >
> > Does CREATE DATABASE convert text?=C2=A0 (I think you might be mi= sunderstanding the purpose of the pg_conversion table.)
>
> No it does not.
>
> But it has an option that can be chosen and supplied to the command...=
>
> So when I write "CREATE DATABASE mydb ECODING =3D BIG5", wha= t will happen?
>
> Moreover, I'm curious - if I chose "BIG5", there are onl= y number of
> available collate/ctype pairs.
> How do I choose which one to present to the user.
> Because there is not one default "BIG5" - there are 3 defaul= t "BIG5"s.
>
> Thank you.
>
> >
> > 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.
> >
> > --
> > Death to <Redacted>, and butter sauce.
> > Don't boil me, I'm still alive.
> > <Redacted> lobster!


--
Death to <Redacted>, and butter sauce.Don't boil me, I'm still alive.
<Redacted> lobs= ter!
--000000000000a37642064fef8b1c--