Re: BUG #6761: unexpected behaviour of 'now'::timestamp - Mailing list pgsql-bugs

Pavel Stehule <pavel.stehule@gmail.com> writes:
> this is not bug - it is consequence of plan cache

FWIW, there is documentation of this issue near the end of
http://www.postgresql.org/docs/9.1/static/plpgsql-implementation.html#PLPGSQL-PLAN-CACHING

This exact case isn't covered in the examples, but the point is that the
expression 'now'::timestamp will get folded to a timestamp constant during
planning, and then not replanned later.  As Pavel says, it's a lot safer
to use one of the variants of the now() function.

            regards, tom lane