Very high effective_cache_size == worse performance?

Поиск
Список
Период
Сортировка
От David Kerr
Тема Very high effective_cache_size == worse performance?
Дата
Msg-id 20100420173936.GA50886@mr-paradox.net
обсуждение исходный текст
Ответы Re: Very high effective_cache_size == worse performance?  ("Joshua D. Drake" <jd@commandprompt.com>)
Re: Very high effective_cache_size == worse performance?  (Robert Haas <robertmhaas@gmail.com>)
Re: Very high effective_cache_size == worse performance?  (Scott Marlowe <scott.marlowe@gmail.com>)
Re: Very high effective_cache_size == worse performance?  ("Joshua D. Drake" <jd@commandprompt.com>)
Список pgsql-performance
Howdy all,

I've got a huge server running just postgres. It's got 48 cores and 256GB of ram. Redhat 5.4, Postgres 8.3.9.
64bit OS. No users currently.

I've got a J2EE app that loads data into the DB, it's got logic behind it so it's not a simple bulk load, so
i don't think we can use copy.

Based on the tuning guides, it set my effective_cache_size to 128GB (1/2 the available memory) on the box.

When I ran my load, it took aproximately 15 hours to do load 20 million records. I thought this was odd because
on a much smaller machine I was able to do that same amount of records in 6 hours.

My initial thought was hardware issues so we got sar, vmstat, etc all running on the box and they didn't give
any indication that we had resource issues.

So I decided to just make the 2 PG config files look the same. (the only change was dropping effective_cache_size
from 128GB to 2GB).

Now the large box performs the same as the smaller box. (which is fine).

incidentally, both tests were starting from a blank database.

Is this expected?

Thanks!

Dave

В списке pgsql-performance по дате отправления:

Предыдущее
От: "Kevin Grittner"
Дата:
Сообщение: Re: [JDBC] SOLVED ... Re: Getting rid of a cursor from JDBC .... Re: Re: HELP: How to tame the 8.3.x JDBC driver with a biq guery result set
Следующее
От: "Joshua D. Drake"
Дата:
Сообщение: Re: Very high effective_cache_size == worse performance?