Greg,
> For such an application this would be a major foot-gun which would give
> a false sense of security simultaneously causing random outages and not
> providing even the protection you're counting on.
Hmmm. That sounds like a call for some testing. While our cost estimation
has some issues, I don't think it's unreliable as all that. And it's easy
enough to document the limitations. If it's 80% accurate, then it's
fixing more problems than it causes. If it's 30% accurate, then obviously
it's a bad idea.
Personally, I don't see much use for this interactively, because an
experienced DBA can easily enough run an EXPLAIN before running the query.
I usually do, on production systems.
--
--Josh
Josh Berkus
PostgreSQL
San Francisco