Re: Extended statistics is not working on Vars hidden under a RelabelType

Robert Haas <robertmhaas@gmail.com>

From: Robert Haas <robertmhaas@gmail.com>
To: David Rowley <david.rowley@2ndquadrant.com>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>, Álvaro Herrera <alvaro.herrera@2ndquadrant.com>, Tomas Vondra <tomas.vondra@2ndquadrant.com>
Date: 2017-10-14T17:49:54Z
Lists: pgsql-hackers
On Fri, Oct 13, 2017 at 4:49 PM, David Rowley
<david.rowley@2ndquadrant.com> wrote:
> tps = 8282.481310 (including connections establishing)
> tps = 8282.750821 (excluding connections establishing)

vs.

> tps = 8520.822410 (including connections establishing)
> tps = 8521.132784 (excluding connections establishing)
>
> With the patch we are making use of the extended statistics, which we
> do expect to be more work for the planner. Although, we didn't add
> extended statistics to speed up the planner.

Sure, I understand.  That's actually a pretty substantial regression -
I guess that means that it's pretty important to avoid creating
extended statistics that are not needed, at least for short-running
queries.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company


Commits

  1. Infer functional dependency past RelabelType