Re: Removing unneeded self joins

From: Konstantin Knizhnik <k(dot)knizhnik(at)postgrespro(dot)ru>
To: Andrey Lepikhov <a(dot)lepikhov(at)postgrespro(dot)ru>, Thomas Munro <thomas(dot)munro(at)gmail(dot)com>
Cc: David Rowley <david(dot)rowley(at)2ndquadrant(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>, Arseny Sher <a(dot)sher(at)postgrespro(dot)ru>
Subject: Re: Removing unneeded self joins
Date: 2019-08-07 16:23:34
Message-ID: bfcdcf79-d726-3986-597e-bbd9b68a67cc@postgrespro.ru
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On 05.08.2019 14:24, Andrey Lepikhov wrote:
>
>
> On 02/08/2019 04:54, Thomas Munro wrote:
>> On Thu, Jun 27, 2019 at 6:42 PM Andrey Lepikhov
>> <a(dot)lepikhov(at)postgrespro(dot)ru> wrote:
>>> Version v.17 of the patch that fix the bug see in attachment.
>>
>> While moving this to the September CF, I noticed that it needs to be
>> updated for the recent pg_list.h API changes.
> The patch was updated:
> 1. Changes caused by pg_list.h API changes.
> 2. Fix the problem of joint clause_relids and required_relids changes
> [1].
> 3. Add eclass mentions of removed relation into the kept relation
> (field eclass_indexes was introduced by commit 3373c71553).
>
> [1]
> https://www.postgresql.org/message-id/flat/5c21029d-81a2-c999-6744-6a898fcc9a19%40postgrespro.ru
>

One more bug is fixed in this patch: OR clauses were not correctly
updated in case of self join removal.

--
Konstantin Knizhnik
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company

Attachment Content-Type Size
0001-Remove-self-joins-v19.patch text/x-patch 67.5 KB

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