| From: | Alexander Pyhalov <a(dot)pyhalov(at)postgrespro(dot)ru> |
|---|---|
| To: | "Fujii(dot)Yuki(at)df(dot)MitsubishiElectric(dot)co(dot)jp" <Fujii(dot)Yuki(at)df(dot)mitsubishielectric(dot)co(dot)jp> |
| Cc: | Bruce Momjian <bruce(at)momjian(dot)us>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>, "Finnerty, Jim" <jfinnert(at)amazon(dot)com>, Andres Freund <andres(at)anarazel(dot)de>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Tomas Vondra <tomas(dot)vondra(at)enterprisedb(dot)com>, Julien Rouhaud <rjuju123(at)gmail(dot)com>, Daniel Gustafsson <daniel(at)yesql(dot)se> |
| Subject: | Re: Partial aggregates pushdown |
| Date: | 2023-09-27 12:36:34 |
| Message-ID: | 3c97067f40503bd8ebb3659f5daa2ff5@postgrespro.ru |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
Fujii(dot)Yuki(at)df(dot)MitsubishiElectric(dot)co(dot)jp писал 2023-09-27 01:35:
> Hi Mr.Momjian, Mr.Pyhalov.
>
> Tuesday, 26 September 2023 22:15 Alexander Pyhalov
> <a(dot)pyhalov(at)postgrespro(dot)ru>:
>> Do you mean that extra->partial_target->sortgrouprefs is not replaced,
>> and so we preserve tlesortgroupref numbers?
> Yes, that is correct.
>
>> I'm suspicious about rewriting extra->partial_target->exprs with
>> partial_target->exprs - I'm still not sure why we
>> don't we loose information, added by add_column_to_pathtarget() to
>> extra->partial_target->exprs?
>>
Hi.
In postgres_fdw.sql
"Partial aggregates are unsafe to push down having clause when there are
partial aggregates" - this comment likely should be fixed.
Some comments should be added to setGroupClausePartial() and to
make_partial_grouping_target() - especially why setGroupClausePartial()
is called prior to add_new_columns_to_pathtarget().
I'm not sure that I like this mechanics of adding sort group clauses -
it seems we do in core additional work, which is of use only for
one extension, but at least it seems to be working.
--
Best regards,
Alexander Pyhalov,
Postgres Professional
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Masahiko Sawada | 2023-09-27 12:39:45 | Re: Testing autovacuum wraparound (including failsafe) |
| Previous Message | shveta malik | 2023-09-27 12:03:19 | Re: Synchronizing slots from primary to standby |