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From: Andrei Lepikhov <[email protected]>
To: Frédéric Yhuel <[email protected]>
To: Tom Lane <[email protected]>
Cc: [email protected] <[email protected]>
Cc: Jehan-Guillaume de Rorthais <[email protected]>
Cc: Christophe Courtois <[email protected]>
Cc: Laurenz Albe <[email protected]>
Subject: Re: Indexes on expressions with multiple columns and operators
Date: Mon, 22 Sep 2025 15:57:43 +0200
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>
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On 22/9/2025 15:37, Frédéric Yhuel wrote:
> I wonder if this is an argument in favour of decoupling the sample size 
> and the precision of the statistics. Here, we basically want the sample 
> size to be as big as the table in order to include the few (NULL, 
> WARNING) values.
I also have seen how repeating ANALYZE on the same database drastically 
changes query plans ;(.
It seems to me that with massive samples, many of the ANALYZE algorithms 
should be rewritten. In principle, statistical hooks exist. So, it is 
possible to invent an independent table analyser which will scan the 
whole table to get precise statistics.

-- 
regards, Andrei Lepikhov

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