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

Re: Postgresql 8.0 beta 1 - strange cpu usage statistics and slow vacuuming

From: Shelby Cain <alyandon(at)yahoo(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-general <pgsql-general(at)postgresql(dot)org>,pgsql-hackers-win32(at)postgresql(dot)org
Subject: Re: Postgresql 8.0 beta 1 - strange cpu usage statistics and slow vacuuming
Date: 2004-08-19 18:49:11
Message-ID: 20040819184911.68890.qmail@web41606.mail.yahoo.com (view raw or flat)
Thread:
Lists: pgsql-generalpgsql-hackers-win32
--- Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> 
> > My other concern is the length of time that vacuum
> > runs when cost based vacuuming is disabled.
> 
> Are you sure you had cost-based vac disabled?  I
> tried to reproduce
> your experiment here.  I saw some degradation in
> vacuuming speed
> but not nearly as large as you're reporting (85 vs
> 73 seconds),
> and as far as I could tell it was still maxing out
> my disk.
> But the behavior you're describing is exactly what
> I'd expect if
> cost-based vac was on.
> 

I'm pretty certain.  Here are my settings:

vacuum_cost_delay = 0		# 0-1000 milliseconds
vacuum_cost_page_hit = 1	# 0-10000 credits
vacuum_cost_page_miss = 10	# 0-10000 credits
vacuum_cost_page_dirty = 20	# 0-10000 credits
vacuum_cost_limit = 200		# 0-10000 credits

From looking at vacuum.c I gathered vacuum_cost_delay
must be >0 to enable the feature - correct?

Regards,

Shelby Cain




		
__________________________________
Do you Yahoo!?
Yahoo! Mail - 50x more storage than other providers!
http://promotions.yahoo.com/new_mail

Responses

pgsql-hackers-win32 by date

Next:From: Tom LaneDate: 2004-08-19 19:16:05
Subject: Re: Postgresql 8.0 beta 1 - strange cpu usage statistics and slow vacuuming
Previous:From: Rodrigo MorenoDate: 2004-08-19 17:53:40
Subject: RES: InitDB Failure on install

pgsql-general by date

Next:From: Tom LaneDate: 2004-08-19 19:16:05
Subject: Re: Postgresql 8.0 beta 1 - strange cpu usage statistics and slow vacuuming
Previous:From: Oleg BartunovDate: 2004-08-19 18:47:13
Subject: Re: Finally tsearch works ... somehow... remain a few

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group