Re: Where can I get the number of plans that considered by Planner?

What I want to count is the number of plans that have been considered
cheapest_path. Since if a path is considered to be a cheapest_path, the
postgres optimizer need to spent time on comparison. I think this is what I
want.

2009/10/4 Martijn van Oosterhout <kleptog(at)svana(dot)org>

> On Sat, Oct 03, 2009 at 04:20:59PM +1000, ????????? wrote:
> > Since I also need to consider gego, is this the best way to do it?
>
> I think you need to be clearer about what you're trying to count.
> Consider a nestjoin plan where:
>
> - For the inner side it considers 7 paths and throws away 4.
> - For the outer side it considers 6 paths and throws away 2.
>
> Do you want the number 3*4=12 or 7*6=42? Or something in between (what
> if in addition to a nestjoin plan otther possibilities are possible).
>
> As you can see, you can't talk about complete plans because they don't
> exist until right at the end, until then it's just considering how to
> combine different paths in sensible ways.
>
> Have a nice day,
> --
> Martijn van Oosterhout <kleptog(at)svana(dot)org> http://svana.org/kleptog/
> > Please line up in a tree and maintain the heap invariant while
> > boarding. Thank you for flying nlogn airlines.
>
> -----BEGIN PGP SIGNATURE-----
> Version: GnuPG v1.4.9 (GNU/Linux)
>
> iD8DBQFKyIiaIB7bNG8LQkwRAklcAJsFBOQE/xAscZm0ok4WwxVh+C6x8ACfYuNz
> G4GpDdQ4IuTXGWc5QHhD5dc=
> =ynTH
> -----END PGP SIGNATURE-----
>
>