Re: Performance UPDATE/INSERT

Поиск
Список
Период
Сортировка
От A. Kretschmer
Тема Re: Performance UPDATE/INSERT
Дата
Msg-id 20060411102756.GF5520@webserv.wug-glas.de
обсуждение исходный текст
Ответ на Re: Performance UPDATE/INSERT  (Alban Hertroys <alban@magproductions.nl>)
Список pgsql-general
am  11.04.2006, um 12:15:41 +0200 mailte Alban Hertroys folgendes:
> MG wrote:
> >I have to improve the performance of the UPDATES and I was wondering why
> >the UPDATEs need twice as long as the INSERTs.
>
> IIRC, an UPDATE is a DELETE/INSERT combo. That's because the original
> record still needs to be visible to other existing transactions (because of
> MVCC). You can't change its data but need to create a new record instead
> and mark the original as obsolete.

Correctly, and thats why we need VACUUM to clean the space on the disk.


HTH, Andreas
--
Andreas Kretschmer    (Kontakt: siehe Header)
Heynitz:  035242/47215,      D1: 0160/7141639
GnuPG-ID 0x3FFF606C http://wwwkeys.de.pgp.net
 ===    Schollglas Unternehmensgruppe    ===

В списке pgsql-general по дате отправления:

Предыдущее
От: Alban Hertroys
Дата:
Сообщение: Re: trigger firing order
Следующее
От: "Dave Page"
Дата:
Сообщение: Re: Debian package for freeradius_postgresql module