Message-ID: <8cf87fc0-1f79-4427-8134-9245a1a52cf4@gmail.com>
Date: Tue, 28 Jan 2025 15:42:38 +0700
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Subject: Re: POC, WIP: OR-clause support for indexes
From: Andrei Lepikhov <lepihov@gmail.com>
To: Alexander Korotkov <aekorotkov@gmail.com>
Cc: Alena Rybakina <a.rybakina@postgrespro.ru>,
 Ranier Vilela <ranier.vf@gmail.com>, Alexander Lakhin <exclusion@gmail.com>,
 jian he <jian.universality@gmail.com>, Robert Haas <robertmhaas@gmail.com>,
 Nikolay Shaplov <dhyan@nataraj.su>, pgsql-hackers@lists.postgresql.org,
 pgsql-hackers@postgresql.org, Peter Geoghegan <pg@bowt.ie>,
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 Peter Eisentraut <peter@eisentraut.org>
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On 1/28/25 11:36, Andrei Lepikhov wrote:
> On 1/27/25 16:50, Alexander Korotkov wrote:
> qsort(matches, n, sizeof(OrArgIndexMatch), or_arg_index_match_cmp);
> 
> To fit an index, the order of elements in the target array of the 
> `ScalarArrayOpExpr` may change compared to the initial list of OR 
> expressions. If there are indexes that cover the same set of columns but 
> in reverse order, this could potentially alter the position of a 
> Subplan. However, I believe this is a rare case; it is supported by the 
> initial OR path and should be acceptable.
I beg your pardon - I forgot that we've restricted the feature's scope 
and can't combine OR clauses into ScalarArrayOpExpr if the args list 
contains references to different columns.
So, my note can't be applied here.

-- 
regards, Andrei Lepikhov