Bruce Momjian wrote:
>
<snip>
> You mean:
>
> #random_page_cost = 4
> #cpu_tuple_cost = 0.01
> #cpu_index_tuple_cost = 0.001
> #cpu_operator_cost = 0.0025
>
> Thos are relative, of course. We are always looking for better numbers.
>
> > Would a 1.3 ghz Athlon really have a cpu_operator_cost of 0.0025?
> > That would imply that that computer could process 2500 conditionals
> > in the time it would take to make a sequential read. If Postgres
> > is run on a 10K RPM disk vs a 5.4K RPM disk on two different
> > machines with the same processor and speed, these numbers can't
> > hope to be right, one should be about twice as high as the other.
>
> Again, are the correct relative to each other.
I think it's an interesting thought of having a program which will test
a system and work out the Accurate and Correct values for this.
It could become of enormous tuning help. Another thought is to have
PostgreSQL tune these parameters as it goes.
+ Justin
<snip>
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> Bruce Momjian | http://candle.pha.pa.us
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