Re: insert vs select into performance

От: Thomas Finneid
Тема: Re: insert vs select into performance
Дата: ,
Msg-id: 469D2D59.9030106@ifi.uio.no
(см: обсуждение, исходный текст)
Ответ на: Re: insert vs select into performance  (Tom Lane)
Ответы: Re: insert vs select into performance  (Michael Stone)
Список: pgsql-performance

Скрыть дерево обсуждения

insert vs select into performance  (Thomas Finneid, )
 Re: insert vs select into performance  (Michael Glaesemann, )
  Re: insert vs select into performance  (Tom Lane, )
   Re: insert vs select into performance  (Thomas Finneid, )
    Re: insert vs select into performance  (Michael Stone, )
     Re: insert vs select into performance  (Adriaan van Os, )
      Re: insert vs select into performance  (Heikki Linnakangas, )
  Re: insert vs select into performance  (Thomas Finneid, )
   Re: insert vs select into performance  (Michael Stone, )
   Re: insert vs select into performance  (Mark Lewis, )
    Re: insert vs select into performance  (Thomas Finneid, )
   Re: insert vs select into performance  (Michael Glaesemann, )
    Re: insert vs select into performance  (Thomas Finneid, )
 Re: insert vs select into performance  (Arjen van der Meijden, )
  Re: insert vs select into performance  (Thomas Finneid, )
   Re: insert vs select into performance  (Michael Stone, )
    Re: insert vs select into performance  (Thomas Finneid, )
     Re: insert vs select into performance  (Michael Stone, )
 Re: insert vs select into performance  (PFC, )
  Re: insert vs select into performance  (Thomas Finneid, )
   Re: insert vs select into performance  (PFC, )
    Re: insert vs select into performance  (Thomas Finneid, )


Tom Lane wrote:
> Michael Glaesemann <> writes:
>> It would be helpful if you included the actual queries you're using,
>> as there are a number of variables:
>
> Not to mention which PG version he's testing.

Its pg 8.1, for now, I'll be upgrading to a compile optimised 8.2 when I
do the real test on the real server.

(its on kubuntu 6.10 running on a Thinkpad T60 with dual core 1.5,GB RAM
and 100GB SATA, just in case anybody feels that is of any interrest.)


> Since (I think) 8.1,
> SELECT INTO knows that it can substitute one fsync for WAL-logging
> the individual row inserts, since if there's a crash the new table
> will disappear anyway.

I am not sure I understand you correctly here, are you saying that
SELECT INTO in 8.1 disables WAL logging and uses just a single fsync at
the end? in that case it means that I could disable WAL as well and
achieve the same performance, does it not?

regards

thomas



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