Re: Fillfactor effectiveness on existing table

Durgamahesh Manne <maheshpostgres9@gmail.com>

From: Durgamahesh Manne <maheshpostgres9@gmail.com>
To: Laurenz Albe <laurenz.albe@cybertec.at>
Cc: pgsql-general <pgsql-general@lists.postgresql.org>
Date: 2026-02-11T02:28:41Z
Lists: pgsql-general
On Wed, 11 Feb, 2026, 00:01 Laurenz Albe, <laurenz.albe@cybertec.at> wrote:

> On Tue, 2026-02-10 at 21:25 +0530, Durgamahesh Manne wrote:
> > I added fillfactor with less than 100 to existing table then ran vacuum
> full to take effect
> >
> > How to ensure the applied fillfactor is working successfully
> >
> > A ratio of hot updates in catalog table should higher than value of
> n_dead_tup or n_tup_upd? Or what ?
>
> Run
>
>   SELECT n_tup_upd, n_tup_hot_upd
>   FROM pg_stat_all_tables
>   WHERE relname = 'your table';
>
> Then wait for an hour and run the query again.
>
> See how much "n_tup_upd" and "n_tup_hot_upd" increased in that hour.
> If the increase is about the same for both, almost all of your UPDATEs
> are HOT.
>
> Yours,
> Laurenz Albe
>

Hi
@Laurenz Albe <laurenz.albe@cybertec.at>
offer=> SELECT relname AS table_name, n_tup_upd AS updates, n_tup_hot_upd
AS hot_updates FROM pg_stat_all_tables WHERE relname = 'market';
table_name | updates | hot_updates
market | 5997455764 | 3752865557

Regards
Durga Mahesh

>