On Thu, Oct 11, 2012 at 5:59 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> I'm reasonably convinced that this is a good fix for HEAD, but am of two
> minds whether to back-patch it or not. The problem complained of in
> bug #7598 may seem a bit narrow, but the real point is that whether you
> write a cast explicitly or not shouldn't affect planning if the
> semantics are the same. This might well be a significant though
> previously unrecognized performance issue, particularly for people who
> use varchar columns heavily.
I have had a few bad experiences with people getting *really* upset
about plan changes in minor releases, so I would be disinclined to
back-patch this, even if we're fairly sure that it will be an
improvement in most/all cases. It's just not worth the risk of
discovering otherwise.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
