Re: Avoiding bad prepared-statement plans. - Mailing list pgsql-hackers

From Alex Hunsaker
Subject Re: Avoiding bad prepared-statement plans.
Date
Msg-id 34d269d41002261202n492cc8bcoefa6ec77e507fb58@mail.gmail.com
Whole thread Raw
In response to Re: Avoiding bad prepared-statement plans.  (Robert Haas <robertmhaas@gmail.com>)
List pgsql-hackers
On Fri, Feb 26, 2010 at 09:50, Robert Haas <robertmhaas@gmail.com> wrote:
> On Fri, Feb 26, 2010 at 1:29 AM, Alex Hunsaker <badalex@gmail.com> wrote:
>> Prepared plans + exec plan (new guc/ protocol thing):
>>  Use: not quite sure
>>  Problems: slow because it would replan every time
>>  Solutions: use a prepared plan with the appropriate things not
>> parametrized...?
>>
>> [ aka we already have this, its called dont use a prepared statement ]
>
> The point is sometimes you'd like to replan every time, but not
> reparse every time.  There's no way to do that ATM.

So what you save on parse time?  Maybe that's worth it.  I've never
run the numbers nor have I seen them in this thread.  I probably
missed em...  My _hunch_ is planning will on average take
significantly longer than parse time (read in the noise of plan time).But that's unfounded :)  I can certainly imagine
caseswhere you have 
HUGE queries where the parse time too slow-- wont the plan most of the
time be an order of magnitude slower?  Anyway Ill stop until I get a
chance to do _some_ kind of benchmarking, I'm really quite clueless
here.


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