Re: GIN - Generalized Inverted iNdex. Try 3.

Teodor Sigaev <teodor@sigaev.ru> writes:
>> Huh?  Why two?  Either you are allowed to cluster on indexes of this
>> type, or you're not.  I don't see the point of any other distinction.

> amclusterable - as you suggest: Does cluster command  something or not?

This is what we need.

> amclustered   - table on such index is always clustered, cluster command does
>                  nothing, but optimizer/planner takes clustering into
>                  consideration for query planning.

"Takes clustering into account" means nothing.  We don't need that.  Any
such consideration would be handled by the AM-specific amcostestimate
function.
        regards, tom lane