Re: creating CHECK constraints as NOT VALID

On Tue, May 31, 2011 at 12:04 PM, Alvaro Herrera
<alvherre(at)alvh(dot)no-ip(dot)org> wrote:
> This patch allows you to initially declare a CHECK constraint as NOT
> VALID, similar to what we already allow for foreign keys.  That is, you
> create the constraint without scanning the table and after it is
> committed, it is enforced for new rows; later, all rows are checked by
> running ALTER TABLE VALIDATE CONSTRAINT, which doesn't need
> AccessExclusive thus allowing for better concurrency.
>
> The trickiest bit here was realizing that unlike FKs, check constraints
> do inherit, and so needed special treatment for recursion.  Other than
> that I think this was pretty straightforward.
>
> I intend to attempt to apply this to NOT NULL constraints as well, once
> the patch to add them to pg_constraint is in.

Seems like a logical extension of what we have now.

--
Robert Haas
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