The following bug has been logged online:
Bug reference: 6047
Email address: wcting163(at)163(dot)com
PostgreSQL version: 9.0.4
Operating system: WinXP 32bit
Description: prepare p1 as select 'now'::timestamp; then "execute p1"
many times, they return the same time
when i execute the following statements:
prepare p1 as select 'now'::timestamp;
every time i execute statement "execute p1", they all return the same time,
the time when "prepare p1 ..." is created.
but i expect it return the changing time ---- the current time.
1). although i kown that, "the system will convert **now** to a timestamp as
soon as the constant is parsed",
i think this is a bug.
2). maybe you suggest me:
prepare p1 as select now()::timestamp;
then "execute p1" will return the current time.
this is because now() is a builtin function, so we can change "select
'now'::timestamp" to "select now()::timestamp";
but, what about "prepare p1 as select 'today'::timestamp"??
today() is not a builtin function, we can't change it to "select
So, the implementation method of "now" and "today" is different, and
prepare p1 as select 'today'::timestamp;
execute p1;-- will always return the day when the "prepare p1 ..." is
created, even we're in another day.
pgsql-bugs by date
|Next:||From: Craig Ringer||Date: 2011-06-02 08:51:21|
|Subject: Re: BUG #6047: prepare p1 as select 'now'::timestamp; then
"execute p1" many times, they return the same time|
|Previous:||From: Tom Lane||Date: 2011-06-01 20:33:02|
|Subject: Re: [BUGS] BUG #6034: pg_upgrade fails when it should not. |