Re: Parallel Seq Scan vs kernel read ahead
| От | Ranier Vilela |
|---|---|
| Тема | Re: Parallel Seq Scan vs kernel read ahead |
| Дата | |
| Msg-id | CAEudQAraz5Aj7hUR91z1Qmqxwu8rq_Kn+syYEL71S06AFxsyng@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: Parallel Seq Scan vs kernel read ahead (Thomas Munro <thomas.munro@gmail.com>) |
| Ответы |
Re: Parallel Seq Scan vs kernel read ahead
|
| Список | pgsql-hackers |
Em qua., 20 de mai. de 2020 às 21:03, Thomas Munro <thomas.munro@gmail.com> escreveu:
On Thu, May 21, 2020 at 11:51 AM Ranier Vilela <ranier.vf@gmail.com> wrote:
> Em qua., 20 de mai. de 2020 às 20:48, Thomas Munro <thomas.munro@gmail.com> escreveu:
>> On Thu, May 21, 2020 at 11:15 AM Ranier Vilela <ranier.vf@gmail.com> wrote:
>> > postgres=# set max_parallel_workers_per_gather = 0;
>> > Time: 227238,445 ms (03:47,238)
>> > postgres=# set max_parallel_workers_per_gather = 1;
>> > Time: 138027,351 ms (02:18,027)
>>
>> Ok, so it looks like NT/NTFS isn't suffering from this problem.
>> Thanks for testing!
>
> Maybe it wasn’t clear, the tests were done with your patch applied.
Oh! And how do the times look without it?
Vanila Postgres (latest)
create table t as select generate_series(1, 800000000)::int i;
set max_parallel_workers_per_gather = 0;
Time: 210524,317 ms (03:30,524)
set max_parallel_workers_per_gather = 1;
Time: 146982,737 ms (02:26,983)
regards,
Ranier Vilela
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