On Thu, Apr 14, 2016 at 1:01 PM, Andres Freund <andres@anarazel.de> wrote:
> On 2016-04-14 13:16:20 +0200, Andreas Karlsson wrote:
>> I am personally not a fan of the pg_get_Xdef() functions due to their heavy
>> reliance on the syscache which feels rather unsafe in combination with
>> concurrent DDL.
>
> I'm not sure I find that convincing: The state portrayed by the syscache
> is th state COPY/SELECT et al will be using. I think the angle to
> attack this is rather to allow blocking 'globally visible' DDL
> efficiently and correctly, rather than the hack pg_dump is using right now.
Maybe. I think that idea of changing the pg_get_Xdef() stuff to use
the transaction snapshot rather than the latest snapshot might be
worth considering, too.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
