Vernon Wu wrote:
> 12/5/2002 1:06:03 PM, Jochem van Dieten <jochemd@oli.tudelft.nl> wrote:
>
>>You start by using a dataset of realistic size. Sorry, but if the actual
>>time is < 10.00 ms it is rather pointless to optimize further since
>>chance is going to be the biggest factor. And the IN/EXISTS difference
>>is dependent on dataset size.
>
> Do you mean that using "EXIST" is not necessary out-perform using 'IN" even the "explain" say so? What is the right
> size for those two key words?
IIRC, IN might be faster on small datasets, but EXISTS is faster on big
ones. So you have to optimize with a dataset that resembles the actual
dataset you will be using in production as close as possible. I don't
know what the size is at which one gets faster as the other.
Jochem