Re: Add support for (Var op Var) clause in extended MCV statistics - Mailing list pgsql-hackers

From Tomas Vondra
Subject Re: Add support for (Var op Var) clause in extended MCV statistics
Date
Msg-id 73dd8031-b2a0-4ed8-b642-8afb196e6ce8@vondra.me
Whole thread Raw
In response to Re: Add support for (Var op Var) clause in extended MCV statistics  (Alena Rybakina <a.rybakina@postgrespro.ru>)
Responses Re: Add support for (Var op Var) clause in extended MCV statistics
List pgsql-hackers
On 8/12/24 13:44, Alena Rybakina wrote:
> Hi! I think your work is important)
> 

I agree, and I'm grateful someone picked up the original patch. I'll try
to help to keep it moving forward. If the thread gets stuck, feel free
to ping me to take a look.

> I started reviewing it and want to suggest some changes to better code:
> I think we should consider the case where the expression is not neither
> an OpExpr and VarOpVar expression.
> 

Do you have some specific type of clauses in mind? Most of the extended
statistics only really handles this type of clauses, so I'm not sure
it's feasible to extend that - at least not in this patch.

> Have you tested this code with any benchmarks?
>
FWIW I think we need to test two things - that it (a) improves the
estimates and (b) does not have significant overhead.



regards

-- 
Tomas Vondra



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