"Jeroen T. Vermeulen" <jtv@xs4all.nl> writes:
> On Fri, September 1, 2006 16:53, Martijn van Oosterhout wrote:
>
>> Interesting thought. It might be worth trying. But my big question: is
>> all this testing and counting actually going to be faster than just
>> replanning? Postgresql's planner is not that slow.
>
> In the best case (which of course would have to be very frequent for any
> of this to matter in the first place) it's mainly just a short loop
> comparing the call's parameter values to their counterparts stored with
> the plan and update those two-bit confidence counters. You wouldn't
> *believe* how simple you have to keep these things in processor
> architecture. :-)
I think the slow part is trying to figure out whether to count the current
call as a hit or a miss. How do you determine whether the plan you're running
is the best plan without replanning the query?
-- Gregory Stark EnterpriseDB http://www.enterprisedb.com
