Re: *_collapse_limit, geqo_threshold

On Saturday 11 July 2009 18:23:59 Tom Lane wrote:
> On reflection I think the best user API is probably a "geqo_seed" GUC in
> the range 0 to 1, and have GEQO always reset its seed to that value at
> start of a planning cycle.  This ensures plan stability, and if you need
> to experiment with alternative plans you can change to different seed
> values.  The "no reset" behavior doesn't seem to have much real-world
> usefulness, because even if you chance to get a good plan, you have no
> way to reproduce it...
I just realized doing it in a naive way (in geqo()) causes the state to be 
reset multiple times during one query- at every invocation of 
make_rel_from_joinlist.
Does anybody see a problem with that?

Andres