Re: More shared buffers causes lower performances

Поиск
Список
Период
Сортировка
От Pavel Stehule
Тема Re: More shared buffers causes lower performances
Дата
Msg-id 162867790712260912p1e00dd75yfaebf6fffe6d2403@mail.gmail.com
обсуждение исходный текст
Ответ на Re: More shared buffers causes lower performances  ("Guillaume Smet" <guillaume.smet@gmail.com>)
Список pgsql-performance
Hello

I tested it and it is true. In my configuration 1GRam, Fedora 8, is
PostgreSQL most fast with 32M shared buffers :(. Diff is about 5% to
256M

Regards
Pavel Stehule

On 26/12/2007, Guillaume Smet <guillaume.smet@gmail.com> wrote:
> On Dec 26, 2007 12:21 PM, Simon Riggs <simon@2ndquadrant.com> wrote:
> > bgwriter_lru_maxpages = 0
> >
> > So we can see if the bgwriter has any hand in this?
>
> It doesn't change the behaviour I have.
>
> It's not checkpointing either as using pgbench-tools, I can see that
> tps and latency are quite stable during the entire run. Btw, thanks
> Greg for these nice tools.
>
> I thought it may be some sort of lock contention so I made a few tests
> with -N but I have the same behaviour.
>
> Then I decided to perform read-only tests using -S option (pgbench -S
> -s 100 -c 16 -t 30000 -U postgres bench). And still the same
> behaviour:
> shared_buffers=64MB : 20k tps
> shared_buffers=1024MB : 8k tps
>
> Any other idea?
>
> --
> Guillaume
>
> ---------------------------(end of broadcast)---------------------------
> TIP 2: Don't 'kill -9' the postmaster
>

В списке pgsql-performance по дате отправления:

Предыдущее
От: Mark Mielke
Дата:
Сообщение: Re: With 4 disks should I go for RAID 5 or RAID 10
Следующее
От: "Guillaume Smet"
Дата:
Сообщение: Re: More shared buffers causes lower performances