Re: POC: converting Lists into arrays

On Mon, Feb 25, 2019 at 1:51 PM Andres Freund <andres(at)anarazel(dot)de> wrote:
> Those could trivially support distinguisiong at least between lists
> containing pointer, int, oid, or node. But even optionally doing more
> than that would be fairly easy. It's not those modules don't currently
> know the types of elements they're dealing with?
>
>
> > If you add a support for a new datatype, where does that leave
> > stored rules?
>
> We don't maintain stored rules across major versions (they break due to
> a lot of changes), so I don't quite understand that problem.

The point is that the implicit need to have support for serializing
and deserializing everything is something that constrains the design,
and must also constrain the design of any successor data structure.
The contents of pg_list.[ch] are not why it's a PITA to add support
for a new datatype. Also, most of the time the Lists are lists of
nodes, which is essentially an abstract base type for heterogeneous
types anyway. I don't really get what you mean about type safety,
because you haven't spelled it out in a way that acknowledges all of
this.

--
Peter Geoghegan