Subject: Re: Removing unneeded self joins
To: Laurenz Albe <laurenz.albe@cybertec.at>,
 Hywel Carver <hywel@skillerwhale.com>, pgsql-hackers@lists.postgresql.org
Cc: Konstantin Knizhnik <knizhnik@garret.ru>
References: <64486b0b-0404-e39e-322d-0801154901f3@postgrespro.ru>
 <21e15759-dba5-2d2b-dd03-06943ad40378@postgrespro.ru>
 <161553990603.28624.7702383984090736980.pgcf@coridan.postgresql.org>
 <2a6e540a-4c9f-9402-2e02-71e35fcd4dd1@postgrespro.ru>
 <b17c18d9fd379ce2355c355cdb44787a452961ec.camel@cybertec.at>
From: Andrey Lepikhov <a.lepikhov@postgrespro.ru>
Organization: Postgres Professional
Message-ID: <1b4b177a-ef90-d3b9-59b2-5cec182f0efb@postgrespro.ru>
Date: Thu, 1 Jul 2021 08:20:24 +0300
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0)
 Gecko/20100101 Thunderbird/78.11.0
MIME-Version: 1.0
In-Reply-To: <b17c18d9fd379ce2355c355cdb44787a452961ec.camel@cybertec.at>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Archived-At: 
 <https://www.postgresql.org/message-id/1b4b177a-ef90-d3b9-59b2-5cec182f0efb%40postgrespro.ru>
Precedence: bulk

On 30/6/21 18:55, Laurenz Albe wrote:
> On Wed, 2021-06-30 at 14:21 +0300, Andrey Lepikhov wrote:
>> I think, here we could ask more general question: do we want to remove a
>> 'IS NOT NULL' clause from the clause list if the rest of the list
>> implicitly implies it?
> Generally I have the impression that we are not too keen on spending
> planning time on optimizing cases that can be trivially improved by rewriting
> the query.
Thank you, It's strong argument.
Such feature would look better as a part of an enterprise edition.

-- 
regards,
Andrey Lepikhov
Postgres Professional