| From: | Robert Haas <robertmhaas(at)gmail(dot)com> |
|---|---|
| To: | Teodor Sigaev <teodor(at)sigaev(dot)ru> |
| Cc: | "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: [COMMITTERS] pgsql: Improve performance of find_all_inheritors() |
| Date: | 2017-03-27 16:19:05 |
| Message-ID: | CA+TgmoYbfybPpU9N8Jh+sXTO+nqDh9_kfMJp7MvxCmP+0OFDKw@mail.gmail.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-committers pgsql-hackers |
On Mon, Mar 27, 2017 at 12:08 PM, Teodor Sigaev <teodor(at)sigaev(dot)ru> wrote:
> Improve performance of find_all_inheritors()
>
> Previous coding uses three nested loops which obviously were a pain for
> large number of table's children. Patch replaces inner loop with
> a hashmap.
>
> Author: Aleksander Alekseev
> Reviewed-by: me
>
> https://commitfest.postgresql.org/13/1058/
I'm a little worried that this will be noticeably slower when the
number of partitions is small, like 4 or 8 or 16. In other places,
we've found it necessary to support both a list-based strategy and a
hash-based strategy to avoid regressing small cases (e.g.
join_rel_list + join_rel_hash in PlannerInfo, ResourceArray in
resowner.c, etc).
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Teodor Sigaev | 2017-03-27 16:33:50 | pgsql: Fsync directory after creating or unlinking file. |
| Previous Message | Alvaro Herrera | 2017-03-27 16:15:24 | pgsql: Fix thinko in estimate_num_groups |
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Robert Haas | 2017-03-27 16:22:29 | Re: crashes due to setting max_parallel_workers=0 |
| Previous Message | Andres Freund | 2017-03-27 16:18:59 | Re: WIP: Faster Expression Processing v4 |