From: | Gregory Stark <stark(at)enterprisedb(dot)com> |
---|---|
To: | "Jeroen T(dot) Vermeulen" <jtv(at)xs4all(dot)nl> |
Cc: | "Martijn van Oosterhout" <kleptog(at)svana(dot)org>, "Phil Frost" <indigo(at)bitglue(dot)com>, pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: Prepared statements considered harmful |
Date: | 2006-09-01 15:14:32 |
Message-ID: | 87hczrippj.fsf@stark.enterprisedb.com |
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Lists: | pgsql-hackers |
"Jeroen T. Vermeulen" <jtv(at)xs4all(dot)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
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