On Tue, May 31, 2011 at 12:04 PM, Alvaro Herrera
<alvherre@alvh.no-ip.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
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
