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help / color / mirror / Atom feedFrom: Alena Rybakina <[email protected]>
To: jian he <[email protected]>
Cc: Andrei Lepikhov <[email protected]>
Cc: Robert Haas <[email protected]>
Cc: [email protected]
Cc: Alexander Korotkov <[email protected]>
Cc: Peter Geoghegan <[email protected]>
Cc: Finnerty, Jim <[email protected]>
Cc: Marcos Pegoraro <[email protected]>
Cc: [email protected]
Cc: Ranier Vilela <[email protected]>
Cc: Tomas Vondra <[email protected]>
Cc: Peter Eisentraut <[email protected]>
Subject: Re: POC, WIP: OR-clause support for indexes
Date: Wed, 31 Jan 2024 14:10:44 +0300
Message-ID: <[email protected]> (raw)
In-Reply-To: <CACJufxFrZS07oBHMk1_c8P3A84VZ3ysXiZV8NeU6gAnvu+HsVA@mail.gmail.com>
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Hi, thank you for your review and interest in this subject.
On 31.01.2024 13:15, jian he wrote:
> On Wed, Jan 31, 2024 at 10:55 AM jian he<[email protected]> wrote:
>> based on my understanding of
>> https://www.postgresql.org/docs/current/xoper-optimization.html#XOPER-COMMUTATOR
>> I think you need move commutator check right after the `if
>> (get_op_rettype(opno) != BOOLOID)` branch
>>
> I was wrong about this part. sorry for the noise.
>
>
> I have made some changes (attachment).
> * if the operator expression left or right side type category is
> {array | domain | composite}, then don't do the transformation.
> (i am not 10% sure with composite)
To be honest, I'm not sure about this check, because we check the type
of variable there:
if (!IsA(orqual, OpExpr))
{
or_list = lappend(or_list, orqual);
continue;
}
And below:
if (IsA(leftop, Const))
{
opno = get_commutator(opno);
if (!OidIsValid(opno))
{
/* Commuter doesn't exist, we can't reverse the order */
or_list = lappend(or_list, orqual);
continue;
}
nconst_expr = get_rightop(orqual);
const_expr = get_leftop(orqual);
}
else if (IsA(rightop, Const))
{
const_expr = get_rightop(orqual);
nconst_expr = get_leftop(orqual);
}
else
{
or_list = lappend(or_list, orqual);
continue;
}
Isn't that enough?
Besides, some of examples (with ARRAY) works fine:
postgres=# CREATE TABLE sal_emp (
pay_by_quarter integer[],
pay_by_quater1 integer[]
);
CREATE TABLE
postgres=# INSERT INTO sal_emp
VALUES (
'{10000, 10000, 10000, 10000}',
'{1,2,3,4}');
INSERT 0 1
postgres=# select * from sal_emp where pay_by_quarter[1] = 10000 or
pay_by_quarter[1]=2;
pay_by_quarter | pay_by_quater1
---------------------------+----------------
{10000,10000,10000,10000} | {1,2,3,4}
(1 row)
postgres=# explain select * from sal_emp where pay_by_quarter[1] = 10000
or pay_by_quarter[1]=2;
QUERY PLAN
--------------------------------------------------------------
Seq Scan on sal_emp (cost=0.00..21.00 rows=9 width=64)
Filter: (pay_by_quarter[1] = ANY ('{10000,2}'::integer[]))
(2 rows)
> * if the left side of the operator expression node contains volatile
> functions, then don't do the transformation.
I'm also not sure about the volatility check function, because we
perform such a conversion at the parsing stage, and at this stage we
don't have a RelOptInfo variable and especially a RestictInfo such as
PathTarget.
Speaking of NextValueExpr, I couldn't find any examples where the
current patch wouldn't work. I wrote one of them below:
postgres=# create table foo (f1 int, f2 int generated always as identity);
CREATE TABLE
postgres=# insert into foo values(1);
INSERT 0 1
postgres=# explain verbose update foo set f1 = 2 where f1=1 or f1=2 ;
QUERY PLAN
-------------------------------------------------------------------
Update on public.foo (cost=0.00..38.25 rows=0 width=0)
-> Seq Scan on public.foo (cost=0.00..38.25 rows=23 width=10)
Output: 2, ctid
Filter: (foo.f1 = ANY ('{1,2}'::integer[]))
(4 rows)
Maybe I missed something. Do you have any examples?
> * some other minor cosmetic changes.
Thank you, I agree with them.
--
Regards,
Alena Rybakina
Postgres Professional:http://www.postgrespro.com
The Russian Postgres Company
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Subject: Re: POC, WIP: OR-clause support for indexes
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