Date: Sun, 8 Feb 2026 16:06:40 +0100
From: "Peter J. Holzer" <hjp-pgsql@hjp.at>
To: pgsql-general@lists.postgresql.org
Subject: Re: Table bloat threshold limit to trigger repack
Message-ID: <ncmz2o6ia4dmd7up7uyfjerm5jdldkgbbtmdn5pp2couhkqj74@dcxzipl44bxi>
Mail-Followup-To: pgsql-general@lists.postgresql.org
References: <CAJCZkoJF-97BatLoVf1SUBTAX8BrSeX0dgZS+tBOM2imNnGRFQ@mail.gmail.com>
 <CANzqJaCoH2My0YU9cKDDAtSx5vsTyXcpVH9y7WxZCddNmRPU8w@mail.gmail.com>
 <CAJCZkoK-ipKCuiLuc=S=nrNVCPnbsKAUOs6cS9=1kdftcBQFPw@mail.gmail.com>
 <CANzqJaAO4AbdceTA=4bmSA4sCG6viP28hDeeYjYOUe=jzLVbmg@mail.gmail.com>
 <CAJCZkoLc=YXc4H2-aGbp2e-R+WsaLRxiAoj2acLP4=A7z+7xAg@mail.gmail.com>
MIME-Version: 1.0
Content-Type: multipart/signed; micalg=pgp-sha512;
	protocol="application/pgp-signature"; boundary="lvm4fl7jejru2qai"
Content-Disposition: inline
In-Reply-To: <CAJCZkoLc=YXc4H2-aGbp2e-R+WsaLRxiAoj2acLP4=A7z+7xAg@mail.gmail.com>
Archived-At: <https://www.postgresql.org/message-id/ncmz2o6ia4dmd7up7uyfjerm5jdldkgbbtmdn5pp2couhkqj74%40dcxzipl44bxi>
Precedence: bulk


--lvm4fl7jejru2qai
Content-Type: text/plain; protected-headers=v1; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable
Subject: Re: Table bloat threshold limit to trigger repack
MIME-Version: 1.0

On 2026-02-08 15:14:37 +0530, Durgamahesh Manne wrote:
> On Sun, 8 Feb, 2026, 13:15 Ron Johnson, <ronljohnsonjr@gmail.com> wrote:
>     On Sun, Feb 8, 2026 at 12:43=E2=80=AFAM Durgamahesh Manne <
>     maheshpostgres9@gmail.com> wrote:
>         On Sun, 8 Feb, 2026, 10:59 Ron Johnson, <ronljohnsonjr@gmail.com>
>         wrote:
>             On Sat, Feb 7, 2026 at 11:19=E2=80=AFPM Durgamahesh Manne <
>             maheshpostgres9@gmail.com> wrote:
>                 How much table bloat is acceptable before it affects
>                 performance in PostgreSQL?=C2=A0
>=20
>             How big is the table? (For small tables, it doesn't matter.) =
How
>             active is it?=C2=A0 How frequently are records updated?
>=20
>         Table size 100gb
>         I use pgstattuple_approx to get Table bloat is about 16gb as of n=
ow
>         since after repack is done on 27th of January=C2=A0
>         Fillfactor already in place
>         It's very critical application with updates on non partitioned ta=
ble=C2=A0
>=20
>=20
>     What did you set the fillfactor=C2=A0to?
>     Have you minimized the number of indexes?=C2=A0 (That lets HOT work b=
etter.)
>     How long does it take to VACUUM the table?
>=20
> Fillfactor 80

With a fillfactor of 80 you should expect at least 20% of unused space,
or a "bloat" of (100 / 80) - 100 =3D 25 %.

Your 16 GB seem to be less than that which is a bit unexpected, but
might happen if you have an update-heavy workload. If you have 16 GB
more bloat than expected (i.e. you have 67 GB of data and therefore
expected a table size of 67 * 100 / 80 =3D 84 GB, but have 100 GB
instead), that may be worth investigating but isn't terribly concerning
if you have many inserts.

        hjp

--=20
   _  | Peter J. Holzer    | Story must make more sense than reality.
|_|_) |                    |
| |   | hjp@hjp.at         |    -- Charles Stross, "Creative writing
__/   | http://www.hjp.at/ |       challenge!"

--lvm4fl7jejru2qai
Content-Type: application/pgp-signature; name="signature.asc"

-----BEGIN PGP SIGNATURE-----
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=OuRM
-----END PGP SIGNATURE-----

--lvm4fl7jejru2qai--