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From: Siraj G <tosiraj.g@gmail.com>
Date: Wed, 19 Mar 2025 23:06:49 +0530
Message-ID: <CAC5iy60XH8UD1YHeKYzJwihRrFo-ubw4ZcVdbxZE2-2T6dRvAQ@mail.gmail.com>
Subject: Re: size of attributes table is too big
To: Adrian Klaver <adrian.klaver@aklaver.com>
Cc: pgsql-general@lists.postgresql.org
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Hi Adrian

Used this query to find the sizes:

select  relname AS object_name,relkind AS
object_type,pg_size_pretty(pg_relation_size(oid)) AS object_size
FROM pg_class WHERE relnamespace =3D (SELECT oid FROM pg_namespace WHERE
nspname =3D 'pg_catalog')
ORDER BY pg_relation_size(oid) DESC;

We have close to 2000 tables, not sure about the columns. There should be
around 120 - 150 tables that are active, getting the data from DMS.
We do not create/drop tables in our instance unless required.

This is a cloud managed SQL and we do not have any custom setting on the
vacuum part.

On Wed, Mar 19, 2025 at 10:47=E2=80=AFPM Adrian Klaver <adrian.klaver@aklav=
er.com>
wrote:

> On 3/19/25 10:06, Siraj G wrote:
> > Hello!
> >
> > I have a PG (v16) instance which is occupying around 1TB of storage. Ou=
t
>
> Exact version of Postgres 16, include the x in 16.x.
>
> > of this, around 350GB is occupied by the table pg_catalog.pg_attribute.
> > Why is the catalog table's size so big?
> >
> > Here are the sizes:
>
> How did you measure the sizes?
>
> pg_attribute maintains information about table columns, how many table
> columns do you have?
>
> Are you creating/dropping tables on a regular basis?
>
> Is autovacuum running properly?
>
> Have you run VACUUM manually on pg_attribute?
>
> >
> > pg_attribute
> >
> > 338 GB
> > pg_attribute_relid_attnam_index
> >
> > 117 GB
> > pg_attribute_relid_attnum_index
> >
> > 69 GB
> >
> >
> > I think this table must have tons of dead tuples. Please suggest to me
> > if we can purge any data/shrink the size of this table.
> >
> > REgards
> > Siraj
>
> --
> Adrian Klaver
> adrian.klaver@aklaver.com
>
>

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<div dir=3D"ltr">Hi Adrian<div><br></div><div>Used this query to find the s=
izes:</div><div><br></div><div>select=C2=A0=C2=A0relname AS object_name,rel=
kind AS object_type,pg_size_pretty(pg_relation_size(oid)) AS object_size<br=
>FROM pg_class=C2=A0WHERE relnamespace =3D (SELECT oid FROM pg_namespace WH=
ERE nspname =3D &#39;pg_catalog&#39;)<br>ORDER BY pg_relation_size(oid) DES=
C;<br></div><div><br></div><div>We have close to 2000 tables, not sure abou=
t the columns. There should be around 120 - 150 tables that are active, get=
ting the data from DMS.</div><div>We do not create/drop tables in our insta=
nce unless required.</div><div><br></div><div>This is a cloud managed SQL a=
nd we do not have any custom setting on the vacuum part.</div></div><br><di=
v class=3D"gmail_quote gmail_quote_container"><div dir=3D"ltr" class=3D"gma=
il_attr">On Wed, Mar 19, 2025 at 10:47=E2=80=AFPM Adrian Klaver &lt;<a href=
=3D"mailto:adrian.klaver@aklaver.com">adrian.klaver@aklaver.com</a>&gt; wro=
te:<br></div><blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px =
0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">On 3/19/25 1=
0:06, Siraj G wrote:<br>
&gt; Hello!<br>
&gt; <br>
&gt; I have a PG (v16) instance which is occupying around 1TB of storage. O=
ut <br>
<br>
Exact version of Postgres 16, include the x in 16.x.<br>
<br>
&gt; of this, around 350GB is occupied by the table pg_catalog.pg_attribute=
.<br>
&gt; Why is the catalog table&#39;s size so big?<br>
&gt; <br>
&gt; Here are the sizes:<br>
<br>
How did you measure the sizes?<br>
<br>
pg_attribute maintains information about table columns, how many table <br>
columns do you have?<br>
<br>
Are you creating/dropping tables on a regular basis?<br>
<br>
Is autovacuum running properly?<br>
<br>
Have you run VACUUM manually on pg_attribute?<br>
<br>
&gt; <br>
&gt; pg_attribute<br>
&gt;=C2=A0 =C2=A0 =C2=A0 =C2=A0<br>
&gt; 338 GB<br>
&gt; pg_attribute_relid_attnam_index<br>
&gt;=C2=A0 =C2=A0 =C2=A0 =C2=A0<br>
&gt; 117 GB<br>
&gt; pg_attribute_relid_attnum_index<br>
&gt;=C2=A0 =C2=A0 =C2=A0 =C2=A0<br>
&gt; 69 GB<br>
&gt; <br>
&gt; <br>
&gt; I think this table must have tons of dead tuples. Please suggest to me=
 <br>
&gt; if we can purge any data/shrink the size of this table.<br>
&gt; <br>
&gt; REgards<br>
&gt; Siraj<br>
<br>
-- <br>
Adrian Klaver<br>
<a href=3D"mailto:adrian.klaver@aklaver.com" target=3D"_blank">adrian.klave=
r@aklaver.com</a><br>
<br>
</blockquote></div>

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