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From: "David G. Johnston" <david.g.johnston@gmail.com>
Date: Tue, 30 Jun 2026 06:28:39 -0700
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 <CAKFQuwbW-M1nJD2drGYqC3kcbdv7WDDVUP==bqWMczcv6GChyg@mail.gmail.com>
Subject: Re: glossary Data page
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	"pgsql-docs@lists.postgresql.org" <pgsql-docs@lists.postgresql.org>
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On Sunday, June 28, 2026, 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/glossary.html
> Description:
>
> > The basic structure used to store relation data. All pages are of the
> same
> size. Data pages are typically stored on disk, each in a specific file, and
> can be read to shared buffers where they can be modified, becoming dirty.
> They become clean when written to disk. New pages, which initially exist in
> memory only, are also dirty until written.
>
> Am I correct in understanding from this description that all files on the
> disk will be the same size?
> One page = one file?
>

No.  A page is an atomic unit subset of a file.  Files contain many pages.
It would be crazy to limit file sizes to 8kb when we have GB available.

David J.

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On Sunday, June 28, 2026, PG Doc comments form &lt;<a href=3D"mailto:norepl=
y@postgresql.org">noreply@postgresql.org</a>&gt; wrote:<br><blockquote clas=
s=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;pad=
ding-left:1ex">The following documentation comment has been logged on the w=
ebsite:<br>
<br>
Page: <a href=3D"https://www.postgresql.org/docs/18/glossary.html" target=
=3D"_blank">https://www.postgresql.org/<wbr>docs/18/glossary.html</a><br>
Description:<br>
<br>
&gt; The basic structure used to store relation data. All pages are of the =
same<br>
size. Data pages are typically stored on disk, each in a specific file, and=
<br>
can be read to shared buffers where they can be modified, becoming dirty.<b=
r>
They become clean when written to disk. New pages, which initially exist in=
<br>
memory only, are also dirty until written.<br>
<br>
Am I correct in understanding from this description that all files on the<b=
r>
disk will be the same size?<br>
One page =3D one file?<br>
</blockquote><div><br></div><div>No.=C2=A0 A page is an atomic unit subset =
of a file.=C2=A0 Files contain many pages.=C2=A0 It would be crazy to limit=
 file sizes to 8kb when we have GB available.</div><div><br></div><div>Davi=
d J.=C2=A0</div>

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