Re: Re: starting to review the Extend NOT NULL representation to pg_constraint patch

Thanks, I am looking at the new version from Bernd's git repo. One
problem I noticed is that it doesn't really work correctly for all
callers of heap_create_with_catalog -- you're only passing the cooked
not null constraints in DefineRelation, but there are some other places
that call heap_create_with_catalog too. In particular, bootstrap mode
is not handled; I haven't checked the other callers yet. I'm looking
for the best way to handle that.

So, question: do we need pg_constraint rows to exist for all NOT NULL
constraints, including those in system catalogs, and including those in
bootstrap catalogs? If we're going to require that, we're going to need
to add a few initial data lines to the pg_constraint catalog definition,
plus some code to handle the other bootstrap cases (non bootstrap
relations).

We could also declare that we don't need pg_constraint rows for NOT NULL
constraints in system catalogs; but if we're going to do that, I guess
we'd better disallow tables from inheriting system catalogs. Right now
it's not disallowed but I guess it's pretty useless

alvherre=# create table bar() inherits (pg_class);
CREATE TABLE

... on the other hand, being able to use a catalog in a LIKE column
definition sounds like it could be useful:

alvherre=# create table qux (now timestamp, like pg_class);
CREATE TABLE
alvherre=# \d qux
Tabla «public.qux»
Columna | Tipo | Modificadores
----------------+-----------------------------+---------------
now | timestamp without time zone |
relname | name | not null
relnamespace | oid | not null
reltype | oid | not null

--
Álvaro Herrera <alvherre(at)commandprompt(dot)com>
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