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help / color / mirror / Atom feedFrom: Tender Wang <tndrwang@gmail.com>
To: Alexander Korotkov <aekorotkov@gmail.com>
Cc: Kirill Reshke <reshkekirill@gmail.com>
Cc: Fujii Masao <masao.fujii@gmail.com>
Cc: ammmkilo@163.com
Cc: pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #19435: Error: "No relation entry for relid 2" Triggered by Complex Join with Self-Referencing Tables
Date: Wed, 18 Mar 2026 17:46:51 +0800
Message-ID: <CAHewXN=hG+jRgr1huE+hzdT-iLpR7r3c+2B5-4ajXBXfd+zcdQ@mail.gmail.com> (raw)
In-Reply-To: <CAPpHfducqLJ=o3LkoPKGfZJVQuuei+P=2oUF6hX6rzHTZSxoyA@mail.gmail.com>
References: <19435-3cc1a87f291129f1@postgresql.org>
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Alexander Korotkov <aekorotkov@gmail.com> 于2026年3月18日周三 16:40写道：
>
> What about being more generic and call ChangeVarNodes_walker() for the
> node in ChangeVarNodesWalkExpression()? It also works with out case
> and avoids code duplication.
Works for me.
>
> Changes in restrict_infos_logically_equal() makes me a bit uneasy. I
> see, restictinfo's are different by their outer_relids. Why
> outer_relids doesn't matter when required_relids is singleton? More
> general when do outer_relids matter for add_non_redundant_clauses() if
> we're putting restictinfo's into a single list anyway?
(gdb) call nodeToString(binfo_candidates )
{RESTRICTINFO :clause {NULLTEST :arg {VAR :varno 3 :varattno 2
:vartype 16 :vartypmod -1 :varcollid 0 :varnullingrels (b)
:varlevelsup 0 :varreturningtype 0 :varnosyn 3 :varattnosyn 2
:location -1} :nulltesttype 1 :argisrow false :location -1}
:is_pushed_down true :can_join false :pseudoconstant false :has_clone
false :is_clone false :leakproof false :has_volatile 0 :security_level
0 :num_base_rels 1 :clause_relids (b 3) :required_relids (b 3)
:incompatible_relids (b) :outer_relids (b 5) :left_relids (b)
:right_relids (b) :orclause <> :rinfo_serial 3 :eval_cost.startup -1
:eval_cost.per_tuple 0 :norm_selec -1 :outer_selec -1 :mergeopfamilies
<> :left_em <> :right_em <> :outer_is_left false :hashjoinoperator 0
:left_bucketsize -1 :right_bucketsize -1 :left_mcvfreq -1
:right_mcvfreq -1 :left_hasheqoperator 0 :right_hasheqoperator 0}
{RESTRICTINFO :clause {NULLTEST :arg {VAR :varno 3 :varattno 2
:vartype 16 :vartypmod -1 :varcollid 0 :varnullingrels (b)
:varlevelsup 0 :varreturningtype 0 :varnosyn 3 :varattnosyn 2
:location -1} :nulltesttype 1 :argisrow false :location -1}
:is_pushed_down true :can_join true :pseudoconstant false :has_clone
false :is_clone false :leakproof false :has_volatile 2 :security_level
0 :num_base_rels 1 :clause_relids (b 3) :required_relids (b 3)
:incompatible_relids (b) :outer_relids (b) :left_relids (b 3)
:right_relids (b 3) :orclause <> :rinfo_serial 6 :eval_cost.startup -1
:eval_cost.per_tuple 0 :norm_selec -1 :outer_selec -1 :mergeopfamilies
<> :left_em <> :right_em <> :outer_is_left true :hashjoinoperator 91
:left_bucketsize -1 :right_bucketsize -1 :left_mcvfreq -1
:right_mcvfreq -1 :left_hasheqoperator 91 :right_hasheqoperator 91})"
The first is tom1.col_bool IS NOT NULL, its outer_relids (b 5) is
not empty because it's in the nullable side.
The second is added in replace_relid_callback(). Some fields do not match.
In this case, tom1.col_bool IS NOT NULL becomes a filter clause, not a
join clause, and is safe to only check rinfo->clause.
I think it's better to add is_pushed_down == true check, for example:
...
- if (bms_membership(a->required_relids) == BMS_SINGLETON)
+ if (bms_membership(a->required_relids) == BMS_SINGLETON &&
+ a->is_pushed_down &&
+ b->is_pushed_down)
...
Any thought?
--
Thanks,
Tender Wang
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To: pgsql-bugs@postgresql.org
Cc: tndrwang@gmail.com, aekorotkov@gmail.com, reshkekirill@gmail.com, masao.fujii@gmail.com, ammmkilo@163.com, pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #19435: Error: "No relation entry for relid 2" Triggered by Complex Join with Self-Referencing Tables
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