Re: New design for FK-based join selectivity estimation

Simon Riggs <simon(at)2ndquadrant(dot)com> writes:
> On 13 June 2016 at 19:16, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> Another point here is that I'm now unconvinced that restricting the logic
>> to consider only multi-column fkeys is really what we want. It looks to
>> me like the code can also improve estimates in the case where there are
>> multiple single-column FKs linking to the same target relation. That
>> might not be too common for two-table queries, but I bet it happens a
>> lot in three-or-more-table queries.

> Is it realistic that we consider that at this point? Certainly not for
> myself, at least.

It's pretty much built into the redesign I proposed, or so I thought.

regards, tom lane