Skip site navigation (1) Skip section navigation (2)

Re: Low CPU Usage

From: "Scott Marlowe" <scott(dot)marlowe(at)gmail(dot)com>
To: "brauagustin-susc(at)yahoo(dot)com(dot)ar" <brauagustin-susc(at)yahoo(dot)com(dot)ar>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Low CPU Usage
Date: 2007-09-19 19:41:45
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-performance
On 9/19/07, brauagustin-susc(at)yahoo(dot)com(dot)ar <brauagustin-susc(at)yahoo(dot)com(dot)ar> wrote:
> No, changing to fsync off didn't improve performance at all.
> Settings
> work_mem = 64MB
> max_stack_depth = 7MB #in the old server is 8MB but if I set in here give me
> the ulimit error
> max_fsm_pages = 204800
> effective_cache_size = 512MB
> Atuvacuum is off.
> I have run vacuum full and vacuum analyze. The databases are freezed (there
> are no insert, update or delete operations)!!!
> In both servers the query plans are identical with the same costs too!!!
> It's really weird, I don't see high values monitoring disk. Cpu usage is
> about 5% and sometimes a tips of 40 % of disk usage when the query is
> finishing (the first 3 minutes there are some tips of 11 to 16%).

(please don't top post)

This sounds like you've got problems somewhere in your I/O system.
hdparm etc may or may not be seeing the issue.  What do you see in
/var/log/messages or dmesg?

In response to

pgsql-performance by date

Next:From: brauagustin-suscDate: 2007-09-19 19:52:43
Subject: Re: Low CPU Usage
Previous:From: brauagustin-suscDate: 2007-09-19 19:13:33
Subject: Re: Low CPU Usage

Privacy Policy | About PostgreSQL
Copyright © 1996-2017 The PostgreSQL Global Development Group