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From: Richard Guo <guofenglinux@gmail.com>
Date: Wed, 11 Jan 2023 10:45:51 +0800
Message-ID: <CAMbWs49sa00xmyw9TfHLYDsHhsud_YEUm3YRkEE4tJrUDqLCgQ@mail.gmail.com>
Subject: Re: Add proper planner support for ORDER BY / DISTINCT aggregates
To: Dean Rasheed <dean.a.rasheed@gmail.com>
Cc: David Rowley <dgrowleyml@gmail.com>, Ronan Dunklau <ronan.dunklau@aiven.io>, 
	Justin Pryzby <pryzby@telsasoft.com>, Pavel Luzanov <p.luzanov@postgrespro.ru>, 
	Tom Lane <tgl@sss.pgh.pa.us>, pgsql-hackers@lists.postgresql.org, 
	Ranier Vilela <ranier.vf@gmail.com>
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On Tue, Jan 10, 2023 at 6:12 PM Dean Rasheed <dean.a.rasheed@gmail.com>
wrote:

> While doing some random testing, I noticed that the following is broken in
> HEAD:
>
> SELECT COUNT(DISTINCT random()) FROM generate_series(1,10);
>
> ERROR:  ORDER/GROUP BY expression not found in targetlist
>
> It appears to have been broken by 1349d279, though I haven't looked at
> the details.


Yeah, this is definitely broken.  For this query, we try to sort the
scan/join path by random() before performing the Aggregate, which is an
optimization implemented in 1349d2790b.  However the scan/join plan's
tlist does not contain random(), which I think we need to fix.

Thanks
Richard

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<div dir=3D"ltr"><div dir=3D"ltr"><br></div><div class=3D"gmail_quote"><div=
 dir=3D"ltr" class=3D"gmail_attr">On Tue, Jan 10, 2023 at 6:12 PM Dean Rash=
eed &lt;<a href=3D"mailto:dean.a.rasheed@gmail.com">dean.a.rasheed@gmail.co=
m</a>&gt; wrote:<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"=
>While doing some random testing, I noticed that the following is broken in=
 HEAD:<br>
<br>
SELECT COUNT(DISTINCT random()) FROM generate_series(1,10);<br>
<br>
ERROR:=C2=A0 ORDER/GROUP BY expression not found in targetlist<br>
<br>
It appears to have been broken by 1349d279, though I haven&#39;t looked at<=
br>
the details.</blockquote><div>=C2=A0</div><div>Yeah, this is definitely bro=
ken.=C2=A0 For this query, we try to sort the<br>scan/join path by random()=
 before performing the Aggregate, which is an<br>optimization implemented i=
n 1349d2790b.=C2=A0 However the scan/join plan&#39;s<br>tlist does not cont=
ain random(), which I think we need to fix.<br><br>Thanks<br>Richard<br></d=
iv></div></div>

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