Message-ID: <11ee9c04-281f-43c8-a0ff-d481c1e01c09@postgrespro.ru>
Date: Wed, 28 Feb 2024 11:18:59 +0700
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Subject: Re: POC, WIP: OR-clause support for indexes
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To: Alena Rybakina <a.rybakina@postgrespro.ru>,
 jian he <jian.universality@gmail.com>
Cc: Alexander Korotkov <aekorotkov@gmail.com>,
 Robert Haas <robertmhaas@gmail.com>, pgsql-hackers@postgresql.org,
 Peter Geoghegan <pg@bowt.ie>, "Finnerty, Jim" <jfinnert@amazon.com>,
 Marcos Pegoraro <marcos@f10.com.br>, teodor@sigaev.ru,
 Tomas Vondra <tomas.vondra@enterprisedb.com>,
 Peter Eisentraut <peter@eisentraut.org>, Ranier Vilela <ranier.vf@gmail.com>
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From: Andrei Lepikhov <a.lepikhov@postgrespro.ru>
Organization: Postgres Professional
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On 26/2/2024 11:10, Alena Rybakina wrote:
> On 24.02.2024 14:28, jian he wrote:
>> Hi.
>> I wrote the first draft patch of the documentation.
>> it's under the section: Planner Method Configuration 
>> (runtime-config-query.html)
>> but this feature's main meat is in src/backend/parser/parse_expr.c
>> so it may be slightly inconsistent, as mentioned by others.
>>
>> You can further furnish it.
> 
> Thank you for your work. I found a few spelling mistakes - I fixed this 
> and added some information about generating a partial index plan. I 
> attached it.
Thanks Jian and Alena,
It is a good start for the documentation. But I think the runtime-config 
section needs only a condensed description of a feature underlying the 
GUC. The explanations in this section look a bit awkward.
Having looked through the documentation for a better place for a 
detailed explanation, I found array.sgml as a candidate. Also, we have 
the parser's short overview section. I'm unsure about the best place but 
it is better when the server config section.
What's more, there are some weak points in the documentation:
1. We choose constant and variable parts of an expression and don't 
require the constant to be on the right side.
2. We should describe the second part of the feature, where the 
optimiser can split an array to fit the optimal BitmapOr scan path.

-- 
regards,
Andrei Lepikhov
Postgres Professional