Re: Index AM change proposals, redux

Teodor Sigaev <teodor@sigaev.ru> writes:
> Both GIN and GiST make a call of transformation function before indexing value. 
> I suppose, there is no automatic way to set this flag even in case when type of 
> storage and type of indexing value are the same.

> So, I see three variant:
>   - add flag in pg_am
>   - add flag to create operator class and by default it should point to
>     impossibility to get value from index. At least for GIN and GiST.

Yeah, just as messy as I feared :-(.  My inclination for the first pass
would be to just make it a per-AM flag in pg_am.  We could always
complicate matters later.

(Of course, this is all hypothetical since no patch is on the
horizon...)
        regards, tom lane