Re: List of encodings

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(dot)g(dot)johnston(at)gmail(dot)com> wrote:
>>
>> On Friday, April 17, 2026, Igor Korot <ikorot01(at)gmail(dot)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."

>
> 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(dot)klaver(at)aklaver(dot)com