Re: Redundant qualifier elimination

On 14/08/26 13:27, Tom Lane wrote:
> Denis Smirnov <darthunix(at)gmail(dot)com> writes:
>> So I think:
>
>> 1. The patch needs a VOLATILE check and planning-time tests.
>> 2. It fixes the selectivity estimate but does not fix the JIT regression.
>> 3. The main problem is the JIT cost decision: it uses total plan cost but does
>> not account for the number or size of generated JIT functions.
>
> For the record, I do not think we should accept this patch, even
> if the problems you mention get fixed. It would impose nontrivial
> costs on every query --- roughly O(N^2) in the number of restriction
> clauses --- in order to fix badly-written queries, and that is not
> a tradeoff I like. We could doubtless improve the cost by expending
> lots more engineering effort, but it's still catering to badly
> written queries, and we have better places to put the effort.
>
> (There have been plenty of previous discussions along this same line,
> btw.)
>
> regards, tom lane

Thank you for the feedback! I was not aware of such discussions,
thanks for pointing this out.

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Matheus Alcantara
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