Re: Again, sorry, caching, (Tom What do you think: function

mlw wrote:
> Jan Wieck wrote:
> >
> > mlw wrote:
> > > [...]
> > >
> > > IMHO modifying the function manager to allow the return of a full row, and a
> > > "set of" full rows, answers a LOT of issues I have seen over the years with
> > > PostgreSQL extensibility.
> >
> > Sure. Actually I think you'll have an easy project with this
> > one, because all the work has been done by Tom already.
> >
> > The function manager isn't the problem any more. It is that
> > you cannot have such a "set of" function in the rangetable.
> > So you have no mechanism to USE the result.
>
> I'm not sure I follow you. OK, maybe I identified the wrong portion of code.
>
> The idea is that the first return value could return an array of varlenas, one
> for each column, then a set of varlenas, one for each column.
>
> Is there a way to return this to PostgreSQL?

There is a way to return anything. The problem in PostgreSQL
is to actually USE it.

Our idea originally was to extend the capabilities of a
rangetable entry. Currently, rangetable entries can only
hold a relation, which is a table or a view. After rewriting,
they are down to real tables only.

But basically, a rangetable entry should just be a row-
source, so that a function returning a row-set could occur
there too.

In order to avoid multiple calls to the function because of
nestloops and the like, I think when a set function occurs in
a RTE, it's result should be dumped into a sort-tape and that
is used as the row source in the rest of the plan.

Jan

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