On Wed, Jan 23, 2013 at 8:10 AM, Dimitri Fontaine
<dimitri@2ndquadrant.fr> wrote:
> Really, live DDL is not that frequent, and when you do that, you want
> transparent replanning. I can't see any use case where it's important to
> be able to run DDL in a live application yet continue to operate with
> the old (and in cases wrong) plans.
I agree with that, but I think Tom's concern is more with the cost of
too-frequent re-planning. The most obvious case in which DDL might be
frequent enough to cause an issue here is if there is heavy use of
temporary objects - sessions might be rapidly creating and dropping
objects in their own schemas. It would be unfortunate if that forced
continual replanning of queries in other sessions. I think there
could be other cases where this is an issue as well, but the
temp-object case is probably the one that's most likely to matter in
practice.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
