Re: Serious issues with CPU usage

От: Manfred Koizar
Тема: Re: Serious issues with CPU usage
Дата: ,
Msg-id: g8qolvoau4dabgqprbn1abde81f61eol5l@email.aon.at
(см: обсуждение, исходный текст)
Ответ на: Re: Serious issues with CPU usage  (Andri Saar)
Список: pgsql-performance

Скрыть дерево обсуждения

Serious issues with CPU usage  (<>, )
 Re: Serious issues with CPU usage  (Tom Lane, )
  Re: Serious issues with CPU usage  (Andri Saar, )
   Re: Serious issues with CPU usage  ("Shridhar Daithankar", )
   Re: Serious issues with CPU usage  (Manfred Koizar, )
   Re: Serious issues with CPU usage  (Tom Lane, )
    Re: Serious issues with CPU usage  (Andri Saar, )
     Re: Serious issues with CPU usage  ("Shridhar Daithankar", )
 Re: Serious issues with CPU usage  (Hannu Krosing, )

On Mon, 8 Sep 2003 13:50:23 +0300, Andri Saar <>
wrote:
>Basically I do this:
>1) select about ~700 ID's I have to poll
>2) poll them
>3) update those 700 rows in that "table" I used (~2700 rows total).
>
>And I do this cycle once per minute, so yes, I've got a zillion updates. 700
>of 2700 is roughly 25%, so I'd have to vacuum once per minute?

With such a small table VACUUM should be a matter of less than one
second:

fred=# vacuum verbose t;
INFO:  --Relation public.t--
INFO:  Index t_pkey: Pages 65; Tuples 16384: Deleted 4096.
        CPU 0.01s/0.10u sec elapsed 0.21 sec.
INFO:  Removed 4096 tuples in 154 pages.
        CPU 0.04s/0.02u sec elapsed 0.07 sec.
INFO:  Pages 192: Changed 192, Empty 0; Tup 16384: Vac 4096, Keep 0,
UnUsed 0.
        Total CPU 0.08s/0.16u sec elapsed 0.36 sec.
VACUUM
Time: 415.00 ms

And this is on a 400 MHz machine under cygwin, so don't worry if you
have a real computer.

Servus
 Manfred


В списке pgsql-performance по дате сообщения:

От: "scott.marlowe"
Дата:
Сообщение: Re: slow plan for min/max
От: Neil Conway
Дата:
Сообщение: Re: slow plan for min/max