pg.ddx.io  pgsql-hackers@postgresql.org mailing list archive  

help / color / mirror / Atom feed
From: Alexander Lakhin <exclusion@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
To: Richard Guo <guofenglinux@gmail.com>
Cc: Jian Guo <gjian@vmware.com>
Cc: Tomas Vondra <tomas.vondra@enterprisedb.com>
Cc: Hans Buschmann <buschmann@nidsa.net>
Cc: pgsql-hackers@lists.postgresql.org <pgsql-hackers@lists.postgresql.org>
Cc: Zhenghua Lyu <zlyu@vmware.com>
Subject: Re: Wrong rows estimations with joins of CTEs slows queries by more than factor 500
Date: Sat, 6 Jan 2024 12:00:01 +0300
Message-ID: <608a4886-6c60-0f9e-97d5-591256bd4150@gmail.com> (raw)
In-Reply-To: <754093.1700250120@sss.pgh.pa.us>
References: <4504e67078d648cdac3651b2960da6e7@nidsa.net>
	<SN6PR05MB5199BB4BB8C982BB519B6660C417A@SN6PR05MB5199.namprd05.prod.outlook.com>
	<46a7d950-7ca7-8ab9-76dd-f0bc7611c609@enterprisedb.com>
	<SN6PR05MB5199C0095508555B7D8D0D23C41EA@SN6PR05MB5199.namprd05.prod.outlook.com>
	<891440.1699483495@sss.pgh.pa.us>
	<CAMbWs4-W_81Q3ff1Bk3NU_ChRzOJK0njAoJanW-kXnPF0wjd1Q@mail.gmail.com>
	<414317.1700158568@sss.pgh.pa.us>
	<CAMbWs48Z_PvveOeankGA69=V=fqogusRKGVPBUGfYC0zDo1WPA@mail.gmail.com>
	<482957.1700192299@sss.pgh.pa.us>
	<CAMbWs49eVQMgfR-KNALJB15RR5r-zjNtNWnB0j5S=j40gtu1Jg@mail.gmail.com>
	<754093.1700250120@sss.pgh.pa.us>

Hello Tom and Richard,

17.11.2023 22:42, Tom Lane wrote:
> OK.  I pushed the patch after a bit more review: we can simplify
> things some more by using the subroot->parse querytree for all
> tests.  After the previous refactoring, it wasn't buying us anything
> to do some initial tests with the raw querytree.  (The original
> idea of that, I believe, was to avoid doing find_base_rel if we
> could; but now that's not helpful.)

Please look at the following query:
CREATE TABLE t(i int);
INSERT INTO t VALUES (1);
VACUUM ANALYZE t;

WITH ir AS (INSERT INTO t VALUES (2) RETURNING i)
SELECT * FROM ir WHERE i = 2;

which produces ERROR:  no relation entry for relid 1
starting from f7816aec2.

Best regards,
Alexander





view thread (29+ messages)  latest in thread

Message-ID: <608a4886-6c60-0f9e-97d5-591256bd4150@gmail.com>
Permalink:  ../608a4886-6c60-0f9e-97d5-591256bd4150@gmail.com/
Also on:    postgresql.org/message-id/608a4886-6c60-0f9e-97d5-591256bd4150@gmail.com

 · 

reply
Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: pgsql-hackers@postgresql.org
  Cc: exclusion@gmail.com, tgl@sss.pgh.pa.us, guofenglinux@gmail.com, gjian@vmware.com, tomas.vondra@enterprisedb.com, buschmann@nidsa.net, pgsql-hackers@lists.postgresql.org, zlyu@vmware.com
  Subject: Re: Wrong rows estimations with joins of CTEs slows queries by more than factor 500
  In-Reply-To: <608a4886-6c60-0f9e-97d5-591256bd4150@gmail.com>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox