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From: Greg Sabino Mullane <htamfids@gmail.com>
Date: Fri, 14 Nov 2025 08:48:57 -0500
Message-ID: <CAKAnmmLUE=BmgBbkqFp9nuQd95PxHAxx=R3Q_WH2YLT_vYg4YA@mail.gmail.com>
Subject: Re: Pgbackrest info output interpretation
To: KK CHN <kkchn.in@gmail.com>
Cc: pgsql-general@lists.postgresql.org
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The "database size" is going to be your data directory, MINUS your pg_wal
directory, MINUS unlogged/temp relations, and MINUS things that are not
needed for recovery (i.e. all the small pg_ directories such as
pg_subtrans). The "database backup size" is how much of that 3GB is part of
*this* backup - for a full backup, the number will be the same, for diff or
incr, it will be a lot less. The "repo backup size" on the last line is the
compressed size of the previous "database backup size"

How to correlate the pgbackrest ( info) database size, database backup size
> and repo1 backup size     and actual du output on DB cluster.
>

You cannot, really, without deep knowledge of things like which files on
disk map back to unlogged tables. However, du on the datadir minus all pg_
dirs should get you in the ballpark. As a quick example:

cd $DATADIR
du --summarize * | awk '!/pg_/{x=x+$1}END{print x}' | numfmt --to=iec

Cheers,
Greg

--
Crunchy Data - https://www.crunchydata.com
Enterprise Postgres Software Products & Tech Support

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<div dir=3D"ltr"><div dir=3D"ltr">The &quot;database size&quot; is going to=
 be your data directory, MINUS your pg_wal directory, MINUS unlogged/temp r=
elations, and MINUS things=C2=A0that are not needed for recovery (i.e. all =
the small pg_ directories such as pg_subtrans). The &quot;database backup s=
ize&quot; is how much of that 3GB is part of *this* backup - for a full bac=
kup, the number will be the same, for diff or incr, it will be a lot less. =
The &quot;repo backup size&quot; on the last line is the compressed size of=
 the previous &quot;database backup size&quot;<div><br></div></div><div cla=
ss=3D"gmail_quote gmail_quote_container"><blockquote class=3D"gmail_quote" =
style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);pa=
dding-left:1ex"><div dir=3D"ltr"><div>How to correlate the pgbackrest ( inf=
o) database size, database backup size and repo1 backup size =C2=A0 =C2=A0 =
and actual du output on DB cluster.=C2=A0</div></div></blockquote><div><br>=
</div><div>You cannot, really, without deep knowledge of things like which =
files on disk map back to unlogged tables. However, du on the datadir minus=
 all pg_ dirs should get you in the ballpark. As a quick example:</div><div=
><br></div><div>cd $DATADIR</div><div>du --summarize * | awk &#39;!/pg_/{x=
=3Dx+$1}END{print x}&#39; | numfmt --to=3Diec=C2=A0</div><div><br></div><di=
v>Cheers,</div></div><div dir=3D"ltr" class=3D"gmail_signature"><div dir=3D=
"ltr"><div>Greg</div><div><br></div><div>--</div><div>Crunchy Data - <a hre=
f=3D"https://www.crunchydata.com" target=3D"_blank">https://www.crunchydata=
.com</a></div><div>Enterprise Postgres Software Products &amp; Tech Support=
</div><div><br></div></div></div></div>

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