Re:Re: setting the timezone parameter with space cause diff result

Thank you very much for your reply, i'am clear now.
Here is an example, which seems to be a problem of parsing, if format string with FF and TZH:TZM,  but the datetime string without fractional seconds will cause parsing misalignment，example：


postgres=# set timezone='-04:00';
SET
postgres=# 


/* datetime string with fractional second */
postgres=# select to_timestamp('2021-6-9 10:30:30.369 +04:00', 'YYYY-MM-DD HH24:MI:SS.FF3 TZH:TZM');
        to_timestamp        
----------------------------
 2021-06-09 10:30:30.369+04
(1 row)
postgres=# 


/* datetime string without fractional second */
postgres=# select to_timestamp('2021-6-9 10:30:30 +04:00', 'YYYY-MM-DD HH24:MI:SS.FF3 TZH:TZM');
       to_timestamp        
---------------------------
 2021-06-09 14:30:30.04+04
(1 row)
postgres=#














At 2021-06-09 02:02:50, "Tom Lane" <tgl@sss.pgh.pa.us> wrote:
>=?UTF-8?B?55SE5piO5rSL?= <zhenmingyang@yeah.net> writes:
>> /* timezone string with space */
>> postgres=# set timezone=' +04:00 ';
>> SET
>> postgres=# select now();
>>               now              
>> -------------------------------
>>  2021-06-08 05:14:36.486693-03
>> (1 row)
>
>What is happening here is that the setting is being interpreted
>much like 'X+04:00Y'.  That is, it's taken as a POSIX timezone
>specifier with standard-time abbreviation being ' ', daylight-
>savings abbreviation also being ' ', and the daylight-savings
>offset and transition rules all being defaulted.  Your example
>without any spaces is recognized as a POSIX timezone spec
>with no DST part, so that's why it behaves differently.
>
>There's certainly room to quibble about whether a single space
>ought to be considered a valid zone abbreviation.  However,
>this behavior comes directly from the IANA tzcode library,
>so I'm hesitant to change it.
>
>			regards, tom lane