From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andreas Seltenreich <seltenreich@gmx.de>
cc: pgsql-hackers@lists.postgresql.org
Subject: Re: [sqlsmith] Planner error on lateral joins
In-reply-to: <87blfgqa4t.fsf@aurora.ydns.eu>
References: <87blfgqa4t.fsf@aurora.ydns.eu>
Comments: In-reply-to Andreas Seltenreich <seltenreich@gmx.de>
	message dated "Sun, 29 Nov 2020 19:40:50 +0100"
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Date: Sun, 29 Nov 2020 15:39:42 -0500
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Andreas Seltenreich <seltenreich@gmx.de> writes:
> testing with sqlsmith on master at 3df51ca8b3 produced one instance of
> the following error:
>     ERROR:  failed to build any 6-way joins

Thanks for the test case!  The attached modification to use only
longstanding test tables fails back to 9.5, but succeeds in 9.4.
I've not tried to bisect yet.

			regards, tom lane


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Content-Description: lateraljoinbug.sql

select * from
  (select sample_1.f1 as c0
      from int4_tbl as sample_1) as subq_0,
  lateral (select  1
      from
 (select
  subq_0.c0 as c3,
  subq_5.c0 as c7,
  sample_2.q2 as c9
       from
  int8_tbl as sample_2,
  lateral (select
        subq_3.c1 as c0
      from
        int4_tbl as sample_3,
        lateral (select
       sample_2.q1 as c0,
       sample_3.f1 as c1
     from
       public.rtest_interface as ref_0
     ) as subq_1,
        lateral (select
       subq_1.c1 as c1
     from
       int4_tbl as ref_1
     ) as subq_3
      ) as subq_5) as subq_6
   right join int4_tbl as sample_6
   on (true)
      where subq_6.c7 = subq_6.c3) as subq_7;

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