Message-ID: <5e129a8e-5b8d-4a61-9776-59be99a2c14f@gmail.com>
Date: Mon, 19 Aug 2024 19:11:00 +0200
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Subject: Re: BUG #18576: Using EXPLAIN (VERBOSE) in
 information_schema.element_types returns ERROR: failed to find plan for
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Richard Guo <guofenglinux@gmail.com>, pgsql-bugs@lists.postgresql.org
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From: Andrei Lepikhov <lepihov@gmail.com>
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On 19/8/2024 18:36, Tom Lane wrote:
> Andrei Lepikhov <lepihov@gmail.com> writes:
>> Thanks for pushing this!
> 
>> But could you change this code a little bit?
>> I reported this issue a year ago. At that time, it was triggered by the
>> CustomScan node [1]. I haven't found the solution there [2]. Your code
>> looks like a good tradeoff, and if you slightly change the code (like in
>> the attachment), it allows CustomScan to survive such cases.
> 
> This seems like it's making assumptions it shouldn't about what
> CustomScan does.  If there's an argument for doing this, it should
> be added to the adjacent comments.
Hm, I got into this problem many times using CustomScan node. Do you 
have some objections to not allow CustomScan node have a RECORD Var in 
the target list? For example, once I got this bug designing CustomScan 
which gathered lightweight statistics on-the-fly under a Sort and 
GROUP-BY nodes. I didn't change any tuple and had the same target list 
as the child node. Why we should analyse target list and don't use 
CustomScan if it contains Var of specific type?
> 
> (Also, what's with the random change in contrib/Makefile?)
Oops, it's a waste code, pardon.

-- 
regards, Andrei Lepikhov