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