Re: Nested Loop "Killer" on 8.1 - Mailing list pgsql-performance

Greg Stark <gsstark@mit.edu> writes:
> On Wed, Jun 24, 2009 at 1:43 PM, Dave North<DNorth@signiant.com> wrote:
> Why use "like" for a constant string with no % or _ characters? If you
> used = the planner might be able to come up with a better estimate.

Uh, it appears to me the string *does* contain _ characters; perhaps the
OP has neglected to escape those?

The planner does know enough to estimate LIKE with a fixed pattern as
being equivalent to =.  I think it knew that even back in 8.1, but am
too lazy to look right now.

            regards, tom lane