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In-Reply-To: <67bd918d-285e-44d2-a207-f52d9a4c35e6@postgrespro.ru>
From: Alexander Korotkov <aekorotkov@gmail.com>
Date: Thu, 14 Mar 2024 12:39:42 +0200
Message-ID: <CAPpHfdtaHxkXgEAfQDvjfHXcGGESMgSLV=HjCp2VNmq5+Um5gA@mail.gmail.com>
Subject: Re: POC, WIP: OR-clause support for indexes
To: Andrei Lepikhov <a.lepikhov@postgrespro.ru>
Cc: jian he <jian.universality@gmail.com>, Alena Rybakina <a.rybakina@postgrespro.ru>, 
	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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On Thu, Mar 14, 2024 at 12:11=E2=80=AFPM Andrei Lepikhov
<a.lepikhov@postgrespro.ru> wrote:
>
> On 14/3/2024 16:31, Alexander Korotkov wrote:
> > On Wed, Mar 13, 2024 at 2:16=E2=80=AFPM Andrei Lepikhov
> > <a.lepikhov@postgrespro.ru <mailto:a.lepikhov@postgrespro.ru>> wrote:
> >  > On 13/3/2024 18:05, Alexander Korotkov wrote:
> >  > > On Wed, Mar 13, 2024 at 7:52=E2=80=AFAM Andrei Lepikhov
> >  > > Given all of the above, I think moving transformation to the
> >  > > canonicalize_qual() would be the right way to go.
> >  > Ok, I will try to move the code.
> >  > I have no idea about the timings so far. I recall the last time I go=
t
> >  > bogged down in tons of duplicated code. I hope with an almost-ready
> >  > sketch, it will be easier.
> >
> > Thank you!  I'll be looking forward to the updated patch.
> Okay, I moved the 0001-* patch to the prepqual.c module. See it in the
> attachment. I treat it as a transient patch.
> It has positive outcomes as well as negative ones.
> The most damaging result you can see in the partition_prune test:
> partition pruning, in some cases, moved to the executor initialization
> stage. I guess, we should avoid it somehow in the next version.

Thank you, Andrei.  Looks like a very undesirable side effect.  Do you
have any idea why it happens?  Partition pruning should work correctly
for both transformed and non-transformed quals, why does
transformation hurt it?

------
Regards,
Alexander Korotkov