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

Shelby Cain <[email protected]>
Newsgroups gmane.comp.db.postgresql.general,gmane.comp.db.postgresql.devel.win32
Message-ID <[email protected]>
--- Tom Lane <[email protected]> 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




		
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