pg.ddx.io pgsql-hackers@postgresql.org mailing list archive help / color / mirror / Atom feed From: Alexander Lakhin <exclusion@gmail.com>
To: Alexander Korotkov <aekorotkov@gmail.com>
To: Andrei Lepikhov <a.lepikhov@postgrespro.ru>
Cc: Gregory Stark (as CFM) <stark.cfm@gmail.com>
Cc: Michał Kłeczek <michal@kleczek.org>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: Removing unneeded self joins
Date: Tue, 30 Apr 2024 09:00:00 +0300
Message-ID: <0ed2cf02-e655-6ec7-a4fe-52fd8d572f65@gmail.com> (raw )
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Hello Alexander,
23.10.2023 12:47, Alexander Korotkov wrote:
> I think this patch makes substantial improvement to query planning.
> It has received plenty of reviews. The code is currently in quite
> good shape. I didn't manage to find the cases when this optimization
> causes significant overhead to planning time. Even if such cases will
> be spotted there is a GUC option to disable this feature. So, I'll
> push this if there are no objections.
I've discovered another failure, introduced by d3d55ce57.
Please try the following:
CREATE TABLE t (a int unique, b float);
SELECT * FROM t NATURAL JOIN LATERAL
(SELECT * FROM t t2 TABLESAMPLE SYSTEM (t.b)) t2;
With asserts enabled, it triggers
TRAP: failed Assert("!bms_is_member(rti, lateral_relids)"), File: "initsplan.c", Line: 697, PID: 3074054
ExceptionalCondition at assert.c:52:13
create_lateral_join_info at initsplan.c:700:8
query_planner at planmain.c:257:2
grouping_planner at planner.c:1523:17
subquery_planner at planner.c:1098:2
standard_planner at planner.c:415:9
planner at planner.c:282:12
pg_plan_query at postgres.c:904:9
pg_plan_queries at postgres.c:996:11
exec_simple_query at postgres.c:1193:19
PostgresMain at postgres.c:4684:27
With no asserts, I get:
ERROR: failed to construct the join relation
Please take a look at this.
Best regards,
Alexander
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Cc: exclusion@gmail.com, aekorotkov@gmail.com, a.lepikhov@postgrespro.ru, stark.cfm@gmail.com, michal@kleczek.org, pgsql-hackers@lists.postgresql.org
Subject: Re: Removing unneeded self joins
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