Anjan, > But, in PostgreSQL all costs are scaled relative to a page fetch. If we > make both sequential_page_fetch_cost and random_page_cost to "1", then we > need to increase the various cpu_* paramters by multiplying the default > values with appropriate Scaling Factor. Now, we need to determine this > Scaling Factor.
I see, so you're saying that because the real cost of a page fetch has decreased, the CPU_* costs should increase proportionally because relative to the real costs of a page fetch they should be higher? That makes a sort of sense. The problem that you're going to run into is that currently we have no particularly reason to believe that the various cpu_* costs are more than very approximately correct as rules of thumb. So I think you'd be a lot better off trying to come up with some means of computing the real cpu costs of each operation, rather than trying to calculate a multiple of numbers which may be wrong in the first place. I know that someone on this list was working on a tool to digest EXPLAIN ANALYZE results and run statistics on them. Can't remember who, though. Also, I'm still curious on how you're handling shared_mem, work_mem and maintenance_mem. You didn't answer last time. -- Josh Berkus Aglio Database Solutions San Francisco ---------------------------(end of broadcast)--------------------------- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq