Re: List of encodings - Mailing list pgsql-general

Hi, Adrian,

On Sun, Apr 19, 2026 at 4:21 PM Adrian Klaver <adrian.klaver@aklaver.com> wrote:
>
> On 4/19/26 1:27 PM, Igor Korot wrote:
> > Hi, David,
> >
> > On Sat, Apr 18, 2026 at 2:19 AM David G. Johnston
> > <david.g.johnston@gmail.com> wrote:
> >>
> >> On Friday, April 17, 2026, Igor Korot <ikorot01@gmail.com> wrote:
> >>>
> >>> Hi, ALL,
> >>> Does the list shown in
> >>> https://www.postgresql.org/docs/current/multibyte.html#MULTIBYTE-CHARSET-SUPPORTED
> >>> stored somewhere in INFORMATION_SCHEMA?
> >>
> >>
> >> This wouldn’t be under the purview of information schema.  You can find pg-specific pieces though:
> >>
> >> https://www.postgresql.org/docs/current/catalog-pg-conversion.html
> >>
> >> Note the function used to convert ids to names.
> >
> > Tried the following query:
> >
> > SELECT conname AS name, pg_encoding_to_char( conforencoding ) AS
> > encoding, condefault AS default FROM pg_conversion ORDER BY encoding;
> >
> > and got following results (for simplicity I will post only couple of rows):
> >
> >   big5_to_utf8                   | BIG5           | t
> >   big5_to_euc_tw                 | BIG5           | t
> >   big5_to_mic                    | BIG5           | t
> >   euc_cn_to_mic                  | EUC_CN         | t
> >   euc_cn_to_utf8                 | EUC_CN         | t
> >   euc_jis_2004_to_shift_jis_2004 | EUC_JIS_2004   | t
> >   euc_jis_2004_to_utf8           | EUC_JIS_2004   | t
> >   euc_jp_to_mic                  | EUC_JP         | t
> >   euc_jp_to_sjis                 | EUC_JP         | t
> >   euc_jp_to_utf8                 | EUC_JP         | t
> >   euc_kr_to_utf8                 | EUC_KR         | t
> >   euc_kr_to_mic                  | EUC_KR         | t
> >   euc_tw_to_big5                 | EUC_TW         | t
> >   euc_tw_to_utf8                 | EUC_TW         | t
> >   euc_tw_to_mic                  | EUC_TW         | t
> >
> > What I noticed is that all encodings are default, as they all have 't'
> > in the last column.
> >
> > It's a little confusing...
>
> Not if you read the docs:
>
> https://www.postgresql.org/docs/current/catalog-pg-conversion.html
>
> "The catalog pg_conversion describes encoding conversion functions. See
> CREATE CONVERSION for more information."
>
> https://www.postgresql.org/docs/current/sql-createconversion.html
>
> "Conversions that are marked DEFAULT can be used for automatic encoding
> conversion between client and server. To support that usage, two
> conversions, from encoding A to B and from encoding B to A, must be
> defined."

From the https://www.postgresql.org/docs/current/catalog-pg-conversion.html:

[quote]

condefault bool

True if this is the default conversion
[/quote]

So, what info do I trust?

Thank you.

>
>
> >
> > Thx for the help.
> >
> >>
> >>>
> >>>
> >>> Or is it hard coded inside the PostgreSQL codebase?
> >>
> >>
> >>   Yes.  Doesn’t preclude exposing it via SQL but we don’t do so directly.
> >>
> >> David J.
> >
> >
>
>
> --
> Adrian Klaver
> adrian.klaver@aklaver.com