From: a.rybakina <a.rybakina@postgrespro.ru>
To: Lepikhov Andrei <lepikhov@fastmail.com>
Cc: pgsql-bugs@lists.postgresql.org, Дамир Белялов <d.belyalov@postgrespro.ru>
Cc: Richard Guo <guofenglinux@gmail.com>
Cc: Andrei Lepikhov <a.lepikhov@postgrespro.ru>
Subject: Re: EXPLAIN Verbose issue - custom_scan_tlist can directly refer CTE and Subquery
Date: Tue, 10 Oct 2023 17:01:54 +0300
Message-ID: <b6292f36-8856-4cd4-9d6c-ba995a19992f@postgrespro.ru> (raw)
In-Reply-To: <0cbbd87e-1b57-4b7e-9825-19a6fb2f8670@postgrespro.ru>
References: <dfe47e78-f9c3-4f59-a345-591f7fd3ceec@app.fastmail.com>
<CAMbWs49A1VegrUX08on3WdH7b7t7FUE15JT4qk_vsQ_qfHMGhQ@mail.gmail.com>
<ca3f78bc-9775-4c12-97b5-5e03282df3ea@postgrespro.ru>
<0cbbd87e-1b57-4b7e-9825-19a6fb2f8670@postgrespro.ru>
On 09.10.2023 11:41, Andrei Lepikhov wrote:
> After some attempts to resolve this issue, I must admit that we should
> add a non-trivial method in the CustomScan node interface, which would
> be called in the ruleutils code.
> I guess it is too much for such a rare situation. So maybe just add a
> documentation entry on this thing and set a couple of assertions on
> early detection of problems?.
> In the attachment - is an offer on how to change the code.
>
Hi!
I have studied the problem and I agree with your suggestion to disable
the possibility of explaining subqueries in CustomNode for now.
So far I can only find information about HashJoin and ValueScan, but I
expected that this is not what is needed.
(gdb) p *((Plan *)(cscan->custom_plans->elements[0].ptr_value))->lefttree
$29 = {type = T_ValuesScan, startup_cost = 0, total_cost =
0.025000000000000001, plan_rows = 2, plan_width = 4, parallel_aware =
false, parallel_safe = true, async_capable = false, plan_node_id = 0,
targetlist = 0x560fc9979398, qual = 0x0, lefttree = 0x0, righttree =
0x0, initPlan = 0x0, extParam = 0x0, allParam = 0x0}
(gdb) p *((Plan *)(cscan->custom_plans->elements[0].ptr_value))
$30 = {type = T_HashJoin, startup_cost = 0.050000000000000003,
total_cost = 0.10250000000000001, plan_rows = 2, plan_width = 32,
parallel_aware = false, parallel_safe = false, async_capable = false,
plan_node_id = 0, targetlist = 0x560fc9979208, qual = 0x0, lefttree =
0x560fc9979438, righttree = 0x560fc9979958, initPlan = 0x0, extParam =
0x0, allParam = 0x0}
(gdb) p *((Plan *)(cscan->custom_plans->elements[0].ptr_value))->righttree
$31 = {type = T_Hash, startup_cost = 0.025000000000000001, total_cost =
0.025000000000000001, plan_rows = 2, plan_width = 32, parallel_aware =
false, parallel_safe = false, async_capable = false,
plan_node_id = 0, targetlist = 0x560fc9979518, qual = 0x0, lefttree =
0x560fc9979698, righttree = 0x0, initPlan = 0x0, extParam = 0x0,
allParam = 0x0}
(gdb) p *((Plan *)(cscan->custom_plans->elements[0].ptr_value))->lefttree
$32 = {type = T_ValuesScan, startup_cost = 0, total_cost =
0.025000000000000001, plan_rows = 2, plan_width = 4, parallel_aware =
false, parallel_safe = true, async_capable = false, plan_node_id = 0,
targetlist = 0x560fc9979398, qual = 0x0, lefttree = 0x0, righttree =
0x0, initPlan = 0x0, extParam = 0x0, allParam = 0x0}
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To: pgsql-bugs@postgresql.org
Cc: a.rybakina@postgrespro.ru, lepikhov@fastmail.com, d.belyalov@postgrespro.ru, guofenglinux@gmail.com, a.lepikhov@postgrespro.ru
Subject: Re: EXPLAIN Verbose issue - custom_scan_tlist can directly refer CTE and Subquery
In-Reply-To: <b6292f36-8856-4cd4-9d6c-ba995a19992f@postgrespro.ru>
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