Re: WIP: patch to create explicit support for semi and anti joins

On Wed, 2008-08-13 at 23:12 -0400, Tom Lane wrote:

> We're just trying to provide better performance for certain common SQL
> idioms.

Sounds good, but can you explain how this will help? Not questioning it,
just after more information about it.

I'm half way through join removal patch, so this work might extend the
join elimination to semi/anti joins also (hopefully), or it might
(hopefully not) prevent the join elimination altogether. I'll let you
know how I get on.

-- Simon Riggs           www.2ndQuadrant.comPostgreSQL Training, Services and Support