Re: cost_index() and path row estimate.

--On 1. Mai 2015 11:30:51 -0700 Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> No. The non-parameterized paths for a given relation must all have the
> same rowcount estimates; otherwise the path comparison logic fails
> fundamentally. Another way to look at it is that every correct path
> will yield the same number of rows in reality; so it would be wrong to
> give a path that makes use of a partial index a rowcount advantage over
> a path that is not using the partial index but nonetheless is enforcing
> exactly the same set of scan restriction clauses.

Thanks for the explanation.

--
Thanks

Bernd