Re: Super Optimizing Postgres

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>
> --
>   Bruce Momjian                        |  http://candle.pha.pa.us
>   pgman@candle.pha.pa.us               |  (610) 853-3000
>   +  If your life is a hard drive,     |  830 Blythe Avenue
>   +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026
> 
> ---------------------------(end of broadcast)---------------------------
> TIP 4: Don't 'kill -9' the postmaster

-- 
"My grandfather once told me that there are two kinds of people: those
who work and those who take the credit. He told me to try to be in the
first group; there was less competition there."
   - Indira Gandhi