Content-Type: multipart/mixed; boundary="------------mt9skPaibCGJVCy5K3qDjFC6"
Message-ID: <ee0d17cc-240a-44bf-acad-58790efb0153@postgrespro.ru>
Date: Fri, 5 Jan 2024 10:32:26 +0700
MIME-Version: 1.0
User-Agent: Mozilla Thunderbird
Subject: Re: BUG #18261: Inconsistent results of SELECT affected by joined
 subqueries
To: Alexander Korotkov <aekorotkov@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>
Cc: Richard Guo <guofenglinux@gmail.com>, zuming.jiang@inf.ethz.ch,
 pgsql-bugs@lists.postgresql.org
References: <18261-2a75d748c928609b@postgresql.org>
 <CAMbWs48_EAPrc_C5qvK2WGvydHvht1JUnXwer9FVeU7t_zA+MQ@mail.gmail.com>
 <2887250.1703781175@sss.pgh.pa.us>
 <CAPpHfdtwTjDmg0J3g17drXdt6ROxW5HLueSMgpfy+MMHxBHFmw@mail.gmail.com>
Content-Language: en-US
From: Andrei Lepikhov <a.lepikhov@postgrespro.ru>
Organization: Postgres Professional
In-Reply-To: 
 <CAPpHfdtwTjDmg0J3g17drXdt6ROxW5HLueSMgpfy+MMHxBHFmw@mail.gmail.com>
Archived-At: 
 <https://www.postgresql.org/message-id/ee0d17cc-240a-44bf-acad-58790efb0153%40postgrespro.ru>
Precedence: bulk

This is a multi-part message in MIME format.
--------------mt9skPaibCGJVCy5K3qDjFC6
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit

On 2/1/2024 15:02, Alexander Korotkov wrote:
> On Thu, Dec 28, 2023 at 6:32 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> I'd say that that will break the cases rinfo_serial was introduced for.
>> Now, I certainly don't love rinfo_serial and would be happier if we
>> could do without it, but getting rid of it is another research project.
> 
> It's a pity that no regression tests detect that.  The attached patch
> implements the special comparison function, which ignores the
> 'rinfo_serial' field.  This avoids marking 'rinfo_serial' as
> pg_node_attr(equal_ignore).
I've reviewed this patch, and it seems okay. It was a real blunder in 
our understanding of clauses; thanks to all for pointing this out and 
fixing it.
The regression test shows where two fully equal join clauses, applied on 
different join levels, differ by the only required_relids. It covers the 
problem and can be helpful by itself. IMO, one line in this test is 
redundant (see attachment).
The comment on the patch looks okay. But assuming required_relids and 
clause fields of two RestrinctInfos are equal, I can't imagine a 
situation to have different is_pushed_down and incompatible_relids. Is 
it really possible?

-- 
regards,
Andrei Lepikhov
Postgres Professional

--------------mt9skPaibCGJVCy5K3qDjFC6
Content-Type: text/plain; charset=UTF-8; name="tests_arrangement.diff"
Content-Disposition: attachment; filename="tests_arrangement.diff"
Content-Transfer-Encoding: base64
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--------------mt9skPaibCGJVCy5K3qDjFC6--