Re: Removing unneeded self joins

From: Andrey Lepikhov <a(dot)lepikhov(at)postgrespro(dot)ru>
To: Hywel Carver <hywel(at)skillerwhale(dot)com>
Cc: Konstantin Knizhnik <knizhnik(at)garret(dot)ru>, Heikki Linnakangas <hlinnaka(at)iki(dot)fi>, David Rowley <dgrowleyml(at)gmail(dot)com>, Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com>, pgsql-hackers(at)lists(dot)postgresql(dot)org
Subject: Re: Removing unneeded self joins
Date: 2021-05-07 07:23:00
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On 12/3/21 14:05, Hywel Carver wrote:
> I've built and tested this, and it seems to function correctly to me. One question I have is whether the added "IS NOT NULL" filters can be omitted when they're unnecessary. Some of the resulting plans included an "IS NOT NULL" filter on a non-nullable column. To be clear, this is still an improvement (to me) without that.

New version of the feature. Deeply refactored with main goal - to reduce
the code size) and rebased on current master.

Here I didn't work on 'unnecessary IS NOT NULL filter'.

Andrey Lepikhov
Postgres Professional

Attachment Content-Type Size
v26-0001-Remove-self-joins.patch text/plain 61.3 KB

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