Horton

Re: Index Only Scans with functions

David G. Johnston <david.g.johnston@gmail.com>

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From: "David G. Johnston" <david.g.johnston@gmail.com>
To: jb@jbitc.de, pgsql-docs@lists.postgresql.org
Date: 2026-07-06T15:49:36Z
Lists: pgsql-docs 
On Mon, Jul 6, 2026 at 8:44 AM PG Doc comments form <noreply@postgresql.org>
wrote:

> The following documentation comment has been logged on the website:
>
> Page: https://www.postgresql.org/docs/18/indexes-index-only-scans.html
>


> and concludes that an index-only scan is not possible."
>
> I tried to reproduce the behavior, but it used the index (which is good):
>

You haven't demonstrated it using an index ONLY scan which is what that
section is talking about.


>                                                 QUERY PLAN
>
> -----------------------------------------------------------------------------------------------------------
>  Index Scan using t_i1 on t  (cost=0.42..8.69 rows=1 width=4) (actual
> time=0.034..0.035 rows=1.00 loops=1)
>
>

David J.