Re: EXPLAIN ANALYZE not displaying recheck condition

On Fri, Nov 8, 2019 at 10:47 AM Jeff Janes <jeff.janes@gmail.com> wrote:

On Thu, Nov 7, 2019 at 5:04 PM Ryan Lambert <ryan@rustprooflabs.com> wrote:

Hello,

In Pg12 I noticed the output from EXPLAIN ANALYZE no longer displays the recheck condition when using GIST indexes, such as:

I can't reproduce this using postgis 2.5.2 in Pg12.  What version of postgis are you using, and how did you install it?

This looks like an intended outcome of this commit (in postgis, not in PostgreSQL):

commit 2f3e2783e7e1fa57a5a994e0c82d9784e94895b9
Author: Paul Ramsey <pramsey@cleverelephant.ca>
Date:   Wed Mar 6 17:27:24 2019 +0000

    Use "support function" API in PgSQL 12+ to provide index support for ST_Intersects and company, in place of old SQL inlining method.
    Closes #4341
   
My interpretation is that the filter is at least as stringent as the recheck, so there is nothing to recheck.

Cheers,

Jeff