Simon,
> Is the problem "a person interested" or is there another issue there?
IMHO, it's "a person interested".
> Treating the optimizer as a black box is something I'm very used to from
> other RDBMS. My question is, how can you explicitly re-write a query now
> to "improve" it? If there's no way of manipulating queries without
> actually re-writing the optimizer, we're now in a position where we
> aren't able to diagnose when the optimizer isn't working effectively.
Well, there is ... all of the various query cost parameters.
> For my mind, all the people on this list are potential "optimizer
> developers" in the sense that we can all look at queries and see whether
> there is a problem with particular join plans. Providing good cases of
> poor optimization is just what's needed to assist those few that do
> understand the internals to continue improving things.
... which is what this list is for.
But, ultimately, improvements on the planner are still bottlenecked by having
only one developer actually hacking the changes.
--
Josh Berkus
Aglio Database Solutions
San Francisco