RE: inserts bypass encoding conversion

So,  insert into values(chr(226)||chr(128)||chr(166)) actually got stored in database with LATIN1 with single byte
sequence,but when query select * from testutf8, it got converted to UTF8 three byte sequence first ?  

jamet=# select chr(226)||chr(128)||chr(166);
 ?column?
----------
 ...
(1 row)

jamet=# select * from testutf8;
                                      test
--------------------------------------------------------------------------------
 ...

jamet=# select encode(test::bytea,'hex') from testutf8;
                                                                            encode


-------------------------------------------------------------------------------------------------------------------------------------------------------------
-
 e280a6

Thanks,

James

-----Original Message-----
From: Tom Lane <tgl@sss.pgh.pa.us>
Sent: Thursday, August 17, 2023 9:33 AM
To: James Pang (chaolpan) <chaolpan@cisco.com>
Cc: pgsql-admin@lists.postgresql.org
Subject: Re: inserts bypass encoding conversion

"James Pang (chaolpan)" <chaolpan@cisco.com> writes:
>   In this case, the real value stored in database is UTF8 byte sequence
>   instead of LATIN1 encoding text, right?

Not if you have server_encoding = LATIN1, as you stated earlier.
In that case, the data in the database is in LATIN1, and chr() interprets its argument as a LATIN1 code value --- which
happensto look enough like a Unicode code point to be possibly confusing, until you try to use code points that aren't
withinLATIN1. 

            regards, tom lane