On Mon, Jan 26, 2009 at 1:58 PM, Filip Rembiałkowski
<plk.zuber@gmail.com> wrote:
> 2009/1/26 Grzegorz Jaśkiewicz <gryzman@gmail.com>
>>
>> Hey folks,
>>
>> I have question really for all mighty developers, but don't want to
>> spam -hackers with it.
>>
>> why :
>> select * from foo where X in (1,1,1,1,1,1,1,1) --- same values in search.
>> or select * from foo where (x,y) in
>> ((1,2),(1,2),(1,2),(1,2),(1,2),(1,2),(1,2));
>>
>> never gets optimized by planner, etc ?
>
> I would guess that optimizing silly-written queries was always a
> low-priority task...
> EXPLAIN ANALYZE SELECT * FROM atest where id in
> (1,2,3,3,3,3,3,3,3,5,5,5,5,5,5,5,5,5,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1);
> EXPLAIN ANALYZE SELECT * FROM atest where id in (1,2,3,5);
>
> shows that second query is 2.5 times faster than the first ( 0.170 ms /
> 0.070 ms).
the difference isn't so small than :)
silly or not, sometimes you end up with such collection passed on in
some silly languages.
--
GJ