Emil Briggs wrote:

I just mentioned random_page_cost, but you should also tune
effective_cache_size, since that is effectively most of your RAM. It
depends what else is going on in the system, but setting it as high as
say 12-14GB is probably reasonable if it is a dedicated machine. With
random_page_cost 1.5-2, and higher effective_cache_size, you should be
doing pretty well.

I tried playing around with these and they had no effect. It seems the only
thing that makes a difference is cpu_tuple_cost.

I'm surprised. I know cpu_tuple_cost can effect it as well, but usually
the recommended way to get indexed scans is the above two parameters.

When you do "explain analyze" of a query that you have difficulties
with, how are the planner's estimates. Are the estimated number of rows
about equal to the actual number of rows?
If the planner is mis-estimating, there is a whole different set of
tuning to do to help it estimate correctly.


PS> Use reply-all so that your comments go to the list.

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