On Fri, Dec 5, 2014 at 12:27 PM, Amit Langote <
Langote_Amit_f8@lab.ntt.co.jp> wrote:
> From: Amit Kapila [mailto:
amit.kapila16@gmail.com]
> On Thu, Dec 4, 2014 at 10:46 AM, Amit Langote <
Langote_Amit_f8@lab.ntt.co.jp> wrote:
> >
> > > The more SQL way would be records (composite types). That would make
> > > catalog inspection a LOT easier and presumably make it easier to change the
> > > partitioning key (I'm assuming ALTER TYPE cascades to stored data). Records
> > > are stored internally as tuples; not sure if that would be faster than a List of
> > > Consts or a pg_node_tree. Nodes would theoretically allow using things other
> > > than Consts, but I suspect that would be a bad idea.
> > >
> >
> > While I couldn’t find an example in system catalogs where a record/composite type is used, there are instances of pg_node_tree at a number of places like in pg_attrdef and others. Could you please point me to such a usage for reference?
> >
>
> > I think you can check the same by manually creating table
> > with a user-defined type.
>
> > Create type typ as (f1 int, f2 text);
> > Create table part_tab(c1 int, c2 typ);
>
> Is there such a custom-defined type used in some system catalog? Just not sure how one would put together a custom type to use in a system catalog given the way a system catalog is created. That's my concern but it may not be valid.
>
I think you are right. I think in this case we need something similar
to column pg_index.indexprs which is of type pg_node_tree(which
seems to be already suggested by Robert). So may be we can proceed
with this type and see if any one else has better idea.
