From: PG Bug reporting form <noreply@postgresql.org>
To: pgsql-bugs@lists.postgresql.org
Cc: exclusion@gmail.com
Subject: BUG #18953: Planner fails to build plan for complex query with LATERAL references
Date: Tue, 10 Jun 2025 18:00:01 +0000
Message-ID: <18953-1c9883a9d4afeb30@postgresql.org> (raw)
The following bug has been logged on the website:
Bug reference: 18953
Logged by: Alexander Lakhin
Email address: exclusion@gmail.com
PostgreSQL version: 18beta1
Operating system: Ubuntu 24.04
Description:
The following query:
create table tbl1(a int);
create table tbl2(b int);
create table tbl3(c int);
select * from tbl1 left join
(select case when a = 0 then 0 else subq_3.cc end from tbl1,
lateral (select 1 from tbl2 t1, tbl2 t2, tbl2 t3, tbl2 t4) subq_1,
lateral (
select tbl3.c as cc from tbl3, tbl2 t1, tbl2 t2,
lateral (select c, a from tbl2 limit 1) subq_2
) as subq_3
) subq_4 on true;
ends up with:
ERROR: XX000: failed to build any 4-way joins
LOCATION: standard_join_search, allpaths.c:3527
where N in "N-way" depends on the number of tbl2 t2, tbl2 t3, ... in
subq_1.
This is a simplified version of a query generated by SQLsmith.
The first commit this error is raised on is acfcd45ca. On acfcd45ca~1, the
select fails with "ERROR: could not devise a query plan for the given
query". The last commit it executed with no error is 4200a9286.
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Subject: Re: BUG #18953: Planner fails to build plan for complex query with LATERAL references
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