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From: "David G. Johnston" <david.g.johnston@gmail.com>
Date: Thu, 16 Oct 2025 14:11:10 -0400
Message-ID: 
 <CAKFQuwbfQ_uP+vot0ys_wo4cS6ZCpn=aZxhVGZ-tt_4HB7CVHw@mail.gmail.com>
Subject: BPCHAR description in 8.3. Character Types is misleading and
 incomplete
To: Sergei Katkovsky <skatkovsky@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Jeff Davis <pgsql@j-davis.com>,
	"pgsql-docs@lists.postgresql.org" <pgsql-docs@lists.postgresql.org>
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On Thursday, October 16, 2025, Sergei Katkovsky <skatkovsky@gmail.com>
wrote:


> Manual addition is not padding, If it were, then VARCHAR would also be
> "blank-padded", because you can manually add trailing blanks to values
> of this type too. But of course it isn't.
>

The spaces added to the end of a bpchar manually can and are considered
=E2=80=9Cpadding=E2=80=9D - or =E2=80=9Cpresent but lack semantic/value sig=
nificance=E2=80=9D. The reason
they are not padding for varchar is that such spaces are considered part of
the stored value from a semantic perspective.

Think of padding as a noun, not a verb.  =E2=80=9CThe value contains paddin=
g=E2=80=9D.
Not, =E2=80=9C I am padding the value=E2=80=9D.

And yes, this is intended as a way to make the name of the type and its
behavior consistent.  You sorta have to want it to work/make sense; not
fight it on minor nuance.

David J.

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On Thursday, October 16, 2025, Sergei Katkovsky &lt;<a href=3D"mailto:skatk=
ovsky@gmail.com" target=3D"_blank">skatkovsky@gmail.com</a>&gt; wrote:<div>=
=C2=A0</div><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;bo=
rder-left:1px #ccc solid;padding-left:1ex">
Manual addition is not padding, If it were, then VARCHAR would also be<br>
&quot;blank-padded&quot;, because you can manually add trailing blanks to v=
alues<br>
of this type too. But of course it isn&#39;t.<br>
</blockquote><div><br></div><div>The spaces added to the end of a bpchar ma=
nually can and are considered =E2=80=9Cpadding=E2=80=9D - or =E2=80=9Cprese=
nt but lack semantic/value significance=E2=80=9D. The reason they are not p=
adding for varchar is that such spaces are considered part of the stored va=
lue from a semantic perspective.</div><div><br></div><div>Think of padding =
as a noun, not a verb. =C2=A0=E2=80=9CThe value contains padding=E2=80=9D.=
=C2=A0 Not, =E2=80=9C I am padding the value=E2=80=9D.</div><div><br></div>=
<div>And yes, this is intended as a way to make the name of the type and it=
s behavior consistent.=C2=A0 You sorta have to want it to work/make sense; =
not fight it on minor nuance.</div><div><br></div><div>David J.</div><div><=
br></div>

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