Re: BUG #17871: JIT during postgresql_fdw remote_estimates EXPLAIN have very negatively effect on planning time

From: Maxim Boguk <maxim(dot)boguk(at)gmail(dot)com>
To: David Rowley <dgrowleyml(at)gmail(dot)com>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, pgsql-bugs(at)lists(dot)postgresql(dot)org
Subject: Re: BUG #17871: JIT during postgresql_fdw remote_estimates EXPLAIN have very negatively effect on planning time
Date: 2023-03-28 06:21:54
Message-ID: CAK-MWwQCLCymYsgEETCRQ=unZZmwytostZtBAvrcmyLsKMm87Q@mail.gmail.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-bugs

On Tue, Mar 28, 2023 at 5:13 PM David Rowley <dgrowleyml(at)gmail(dot)com> wrote:

> On Tue, 28 Mar 2023 at 17:54, Maxim Boguk <maxim(dot)boguk(at)gmail(dot)com> wrote:
> > During an attempt to create a minimal test case I discovered an effect
> for which I have no explanation:
> > (all tests with jit=on):
> >
> > Run EXPLAIN on the single partition, so far expected results...
> > explain select * from interview_review_info_archive_p028;
> > QUERY PLAN
> >
> -----------------------------------------------------------------------------------------------
> > Seq Scan on interview_review_info_archive_p028 (cost=0.00..361819.08
> rows=34546848 width=40)
> > JIT:
> > Functions: 2
> > Options: Inlining true, Optimization true, Expressions true,
> Deforming true
>
> It could be something like a dropped column forcing projection of the
> SELECT *. You might want to try without SELECT * using some subset of
> columns instead.
>
> Check if columns have been dropped with:
>
> select attnum,attname from pg_Attribute where
> attrelid='interview_review_info_archive_p028'::Regclass;
>
> David
>

Hi David,

You 100% right
negotiation_chat_archive=# explain select
topic_id,review_id,move_to_invitation_state_time,no_interview_reply_time,review_suggestion_chat_message_creation_time
from interview_review_info_archive_p028;
QUERY PLAN

-----------------------------------------------------------------------------------------------
Seq Scan on interview_review_info_archive_p028 (cost=0.00..361921.00
rows=34563080 width=40)

Exceptionally curious case when select * not equivalent select
list_all_columns from table...
Thank you.

--
Maxim Boguk
Senior Postgresql DBA
https://dataegret.com/

Phone UA: +380 99 143 0000
Phone AU: +61 45 218 5678

In response to

Responses

Browse pgsql-bugs by date

  From Date Subject
Next Message Maxim Boguk 2023-03-28 06:28:04 Re: BUG #17871: JIT during postgresql_fdw remote_estimates EXPLAIN have very negatively effect on planning time
Previous Message David Rowley 2023-03-28 06:13:15 Re: BUG #17871: JIT during postgresql_fdw remote_estimates EXPLAIN have very negatively effect on planning time