Re: reducing random_page_cost from 4 to 2 to force index scan

Robert Haas <robertmhaas@gmail.com> writes:
> On Tue, Apr 26, 2011 at 9:04 PM, Merlin Moncure <mmoncure@gmail.com> wrote:
>> The very first thing to check is effective_cache_size and to set it to
>> a reasonable value.

> Actually, effective_cache_size has no impact on costing except when
> planning a nested loop with inner index scan.  So, a query against a
> single table can never benefit from changing that setting.

That's flat out wrong.  It does affect the cost estimate for plain
indexscan (and bitmap indexscan) plans.

            regards, tom lane