Re: index scan and functions

Le lundi 19 juillet 2010, à 17:09:02 +0100, Sam a écrit :
> On Mon, Jul 19, 2010 at 05:55:48PM +0200, arno wrote:
> > But when using a custom function to compute my where parameter
>
> > inet_to_bigint is a function that transform an inet address its integer representation.
>
> > Is there a way, either to put function return value in a variable, or to tell
> > postgres to still use a sequential scan ?
>
> I'd guess your function is labeled as "VOLATILE".  This is saying that
> the function has "side effects", but from the function's name I'd guess
> that it doesn't and the only purpose of calling the function is to get
> its return value.  I'd expect that labeling it as STABLE would cause PG
> to do what you're expecting.  More details here:
>
>   http://www.postgresql.org/docs/current/static/xfunc-volatility.html

Thanks, that's exactly what I was looking for.