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 <202601261426.hr65rf3efvr3@alvherre.pgsql>
In-Reply-To: <202601261426.hr65rf3efvr3@alvherre.pgsql>
From: Srinath Reddy Sadipiralla <srinath2133@gmail.com>
Date: Mon, 26 Jan 2026 21:04:12 +0530
Message-ID: <CAFC+b6qFKkU_NpH1snNc9_iZzpkxgWpUAibEz1tRYGFRSasqCQ@mail.gmail.com>
Subject: Re: Re: Re: BUG #19351: in pg18.1,when not null exists in the table ,
 and add constraint problem.
To: =?UTF-8?Q?=C3=81lvaro_Herrera?= <alvherre@kurilemu.de>
Cc: yanliang lei <msdnchina@163.com>, pgsql-bugs@lists.postgresql.org
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On Mon, Jan 26, 2026 at 8:03=E2=80=AFPM =C3=81lvaro Herrera <alvherre@kuril=
emu.de> wrote:

>
> > I think we can fix this by throwing an error only if this constraint
> > was added directly to the table and not through
> > inheritance/propagation from the parent, we can do this using the
> > "is_local" flag, i have checked and all tests passed.
>
> Hmm, I'm not opposed to this; does it change any other behavior?  I
> think it's important to see whether there are other corner cases that
> would react to this behavior change.  For example, what would happen if
> two existing parents have a not-null constraint on the same column?  Is
> there a change for combined LIKE and regular inheritance?  I think we
> should have reasonable reactions to each of those scenarios:
>
> create table parent (a int not null);
> create table parent2 (a int not null);
>
> create table child1 () inherits (parent, parent2);
> create table child2 () inherits (parent2, parent);
> create table child3 (not null a) inherits (parent2, parent);
>
> create table child4 (like parent) inherits (parent2);
> -- and so on as your imagination allows
>

 Thanks for the pointers, will look into this angle also.

Would you be able to send a patch based on this idea and what I sent
> earlier?
>

sure , I will do that.


--=20
Thanks,
Srinath Reddy Sadipiralla
EDB: https://www.enterprisedb.com/

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<div dir=3D"ltr"><div dir=3D"ltr"><br></div><br><div class=3D"gmail_quote g=
mail_quote_container"><div dir=3D"ltr" class=3D"gmail_attr">On Mon, Jan 26,=
 2026 at 8:03=E2=80=AFPM =C3=81lvaro Herrera &lt;<a href=3D"mailto:alvherre=
@kurilemu.de">alvherre@kurilemu.de</a>&gt; wrote:</div><blockquote class=3D=
"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(2=
04,204,204);padding-left:1ex"><br>
&gt; I think we can fix this by throwing an error only if this constraint<b=
r>
&gt; was added directly to the table and not through<br>
&gt; inheritance/propagation from the parent, we can do this using the<br>
&gt; &quot;is_local&quot; flag, i have checked and all tests passed.<br>
<br>
Hmm, I&#39;m not opposed to this; does it change any other behavior?=C2=A0 =
I<br>
think it&#39;s important to see whether there are other corner cases that<b=
r>
would react to this behavior change.=C2=A0 For example, what would happen i=
f<br>
two existing parents have a not-null constraint on the same column?=C2=A0 I=
s<br>
there a change for combined LIKE and regular inheritance?=C2=A0 I think we<=
br>
should have reasonable reactions to each of those scenarios:<br>
<br>
create table parent (a int not null);<br>
create table parent2 (a int not null);<br>
<br>
create table child1 () inherits (parent, parent2);<br>
create table child2 () inherits (parent2, parent);<br>
create table child3 (not null a) inherits (parent2, parent);<br>
<br>
create table child4 (like parent) inherits (parent2);<br>
-- and so on as your imagination allows<br></blockquote><div><br>=C2=A0Than=
ks for the pointers, will look into this angle also.<br><br></div><blockquo=
te class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px =
solid rgb(204,204,204);padding-left:1ex">
Would you be able to send a patch based on this idea and what I sent<br>
earlier?=C2=A0<br></blockquote><div><br>sure , I will do that.=C2=A0</div><=
/div><div><br clear=3D"all"></div><div><br></div><span class=3D"gmail_signa=
ture_prefix">-- </span><br><div dir=3D"ltr" class=3D"gmail_signature"><div =
dir=3D"ltr"><span style=3D"color:rgb(34,34,34)">Thanks,</span><br style=3D"=
color:rgb(34,34,34)"><span style=3D"color:rgb(34,34,34)">Srinath Reddy Sadi=
piralla</span><br style=3D"color:rgb(34,34,34)"><span style=3D"color:rgb(34=
,34,34)">EDB:=C2=A0</span><a href=3D"https://www.enterprisedb.com/" style=
=3D"color:rgb(17,85,204)" target=3D"_blank">https://www.enterprisedb.com/</=
a></div></div></div>

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