On Tue, Apr 05, 2011 at 09:44:44AM -0400, Robert Haas wrote:
> On Wed, Mar 30, 2011 at 9:32 PM, Noah Misch <noah@leadboat.com> wrote:
> > On Wed, Mar 30, 2011 at 07:50:12PM +0300, Peter Eisentraut wrote:
> >> Here is a patch that addresses this problem.
> >
> > This only works when exactly one typed table uses each composite type having
> > dropped columns. ?With zero users, the placeholder column never gets dropped.
> > Actually, it happens to work for >1 user, but only because ALTER TYPE mistakenly
> > only touches the first table-of-type:
> >
> > create type t as (x int, y int);
> > create table is_a of t;
> > create table is_a2 of t;
> > alter type t drop attribute y cascade, add attribute z int cascade;
> > \d is_a
> > ? ? Table "public.is_a"
> > ?Column | ?Type ? | Modifiers
> > --------+---------+-----------
> > ?x ? ? ?| integer |
> > ?z ? ? ?| integer |
> > Typed table of type: t
> > \d is_a2
> > ? ? Table "public.is_a2"
> > ?Column | ?Type ? | Modifiers
> > --------+---------+-----------
> > ?x ? ? ?| integer |
> > ?y ? ? ?| integer |
> > Typed table of type: t
> >
> > Might be a simple fix; looks like find_typed_table_dependencies() only grabs the
> > first match. ?Incidentally, this led me to notice that you can hang a typed
> > table off a table row type. ?ALTER TABLE never propagates to such typed tables,
> > allowing them to get out of sync:
> >
> > create table t (x int, y int);
> > create table is_a of t;
> > create table is_a2 of t;
> > alter table t drop y, add z int;
> > \d is_a
> > ? ? Table "public.is_a"
> > ?Column | ?Type ? | Modifiers
> > --------+---------+-----------
> > ?x ? ? ?| integer |
> > ?y ? ? ?| integer |
> > Typed table of type: t
> >
> > Perhaps we should disallow the use of table row types in CREATE TABLE ... OF?
> >
> >> It looks like Noah Misch might have found another problem in this area.
> >> We'll have to investigate that.
> >
> > Your bits in dumpCompositeType() are most of what's needed to fix that, I think.
>
> Where are we on this?
Peter, were you planning to complete this? I can take a swing at it, if it
would be helpful.