autovacuum default parameters (was Re: 8.2 is 30% better in pgbench than 8.3)

Gregory Stark wrote:
> "Alvaro Herrera" <alvherre@commandprompt.com> writes:
> 
> >> Alvaro Herrera <alvherre@commandprompt.com> writes:
> >> >
> >> > I am taking the liberty to also lower the vacuum and analyze threshold
> >> > default values to 50, per previous discussion.
> 
> Did we also reach any consensus about lowering the percentage of dead tuples
> in a table before we trigger vacuum? I think 20% is way too high and 5% is
> saner. I actually think it would be better even lower but would be ok with 5%.

We didn't, but while I agree with the idea, I think 5% is too low.  I
don't want autovacuum to get excessively aggressive.  Is 10% not enough?

How about the analyze scale factor, should we keep the current 10%?  I
have less of a problem with reducing it further since analyze is cheaper
than vacuum.

-- 
Alvaro Herrera                                http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.