On Sun, 2004-04-18 at 19:09, Tom Lane wrote:
> Markus Bertheau <twanger@bluetwanger.de> writes:
> > , 17.04.2004, 01:45, Tom Lane :
> >> The planner sees that as "where scope = <some complicated expression>"
> >> and falls back to a default estimate. It won't simplify a sub-select
> >> to a constant. (Some people consider that a feature ;-).)
>
> > Why?
>
> It's the only way to prevent it from simplifying when you don't want it
> to.
I'm having a difficult time coming up with a circumstance where that is
beneficial except when stats are out of whack.
Doesn't a prepared statement also falls back to the default estimate for
variables.
--
Rod Taylor <rbt [at] rbt [dot] ca>
Build A Brighter Lamp :: Linux Apache {middleware} PostgreSQL
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