Re: How is random_page_cost=4 ok?

> I don't think random_page_cost actually corresponds with any real number 
> anymore.  I just treat it as an uncalibrated knob you can turn and 
> benchmark the results at.

And, frankly, not a useful knob.  You get much more useful results out 
of effective_cache_size and cpu_* costs than you get out of messing with 
random_page_cost, unless you're running on SSD or something which would 
justify a lower RPC, or if you're compensating for our poor n-distinct 
estimation for very large tables.

--Josh