Re: Optimizer generates bad plans.

Tom Lane wrote:
> Neil Conway <neilc(at)samurai(dot)com> writes:
> > Interesting. The inconsistency you're seeing is a result of GEQO. I
> > would have hoped that it would have produced a better quality plan
> > more often, but apparently not. On my system, the regular query
> > optimizer handily beats GEQO for this query: it produces more
> > efficienty query plans 100% of the time and takes less time to do so.
> > For *this* query at least, raising geqo_threshold would be a good
> > idea, but that may not be true universally.
>
> The current GEQO threshold was set some time ago; since then, the
> regular optimizer has been improved while the GEQO code hasn't been
> touched. It might well be time to ratchet up the threshold.
>
> Anyone care to do some additional experiments?

Added to TODO:

* Check GUC geqo_threshold to see if it is still accurate

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