Re: Index optimization ?

Tom Lane wrote:

>http://developer.postgresql.org/docs/postgres/xfunc-volatility.html
>
>
Ok, thanks I see why there is these three differant function types, but
I don't quite understand why the value from a volatile function, can't
be used as a index key. Is this because there is no return type garanti,
for the voilatile function too ?

Will the only possible way to fix this be to make a volatile function
with a return type (I know this is not possible now, but in theory) ?

/BL