Re: BUG #18576: Using EXPLAIN (VERBOSE) in information_schema.element_types returns ERROR: failed to find plan for

On 9/8/2024 17:25, Tom Lane wrote:
> I wrote:
>> Richard Guo <guofenglinux@gmail.com> writes:
>>> Agreed.  Do you think it would be helpful to add some assertions to
>>> verify the plan type?
> 
>> I thought about that but didn't experiment with it.  I wonder whether
>> it'd just make the code more fragile.  Still, it might be useful to
>> verify that things are happening as we expect.
> 
> After sleeping on it, I elected to add the Asserts as suggested,
> except in v12 where they'd have had to look different.  That's
> not strictly a matter of laziness: v12's next release will be its
> last, and I've been burned often enough to become very hesitant
> about pushing even slightly-questionable code into an EOL release.
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.

[1] 
https://www.postgresql.org/message-id/3933834e-b657-4ad1-bf4e-5f3fbba7ba14%40app.fastmail.com
[2] 
https://www.postgresql.org/message-id/0cbbd87e-1b57-4b7e-9825-19a6fb2f8670%40postgrespro.ru

-- 
regards, Andrei Lepikhov