Re: Removing unneeded self joins

From: Andrey Lepikhov <a(dot)lepikhov(at)postgrespro(dot)ru>
To: David Rowley <david(dot)rowley(at)2ndquadrant(dot)com>
Cc: 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: 2019-06-27 06:42:05
Message-ID: 8556348d-b5fa-728a-e4db-8dcad9d11e4b@postgrespro.ru
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Alexander Lakhin detected the bug in the 'remove self joins' patch:

test:
=====

CREATE TABLE t (a INT UNIQUE);
INSERT INTO t VALUES (1);
SELECT 1 FROM (SELECT x.* FROM t AS x, t AS y WHERE x.a = y.a) AS q,
LATERAL generate_series(1, q.a) gs(i);

Description:
============

FUNCTIONS, TABLEFUNCS and VALUES plan nodes uses direct link to the rte
table. We need to change varno references to relid which will be kept.

Version v.17 of the patch that fix the bug see in attachment.

--
Andrey Lepikhov
Postgres Professional
https://postgrespro.com
The Russian Postgres Company

Attachment Content-Type Size
0001-Remove-Self-Joins-v17.patch text/x-patch 66.8 KB

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