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From: Tomas Vondra <[email protected]>
To: Heikki Linnakangas <[email protected]>
To: PostgreSQL Hackers <[email protected]>
Subject: Re: BRIN indexes vs. SK_SEARCHARRAY (and preprocessing scan keys)
Date: Sat, 25 Feb 2023 12:45:28 +0100
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>
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On 2/24/23 22:07, Heikki Linnakangas wrote:
> I had a quick look at just the preliminary cleanup patches:
> 
>> 0001-BRIN-bloom-cleanup-20230218.patch
> 
> Looks good to me
> 
>> 0002-BRIN-minmax-multi-cleanup-20230218.patch
> 
> Looks good, although it would feel more natural to me to do it the other
> way round, and define 'matches' as 'bool matches', and use DatumGetBool.
> 

Yeah, probably. I was trying to only do the minimal change because of
(maybe) backpatching this.

> Not new with this patch, but I find the 'matches' and 'matching'
> variables a bit strange. Wouldn't it be simpler to have just one variable?
> 

True. I don't recall why we did it this way.

>> 0003-Introduce-bloom_filter_size-20230218.patch
> 
> Looks good
> 
>> 0004-Add-minmax-multi-inequality-tests-20230218.patch
> 
> Looks good
> 
>> +SELECT i/5 + mod(911 * i + 483, 25),
>> +       i/10 + mod(751 * i + 221, 41)
> 
> Peculiar formulas. Was there a particular reason for these values?
> 

No, not really. I simply wanted a random-looking data, but reproducible
and deterministic. And linear congruential generator is a simple way to
do that. I just picked a couple co-prime numbers, and that's it.


regards

-- 
Tomas Vondra
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

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