> Thomas, > > Thank you for your very detailed and well written description. In > conclusion, I should keep my random_page_cost (3.0) to a value more than > seq_page_cost (1.0)? Is this bad practice or will this suffice for my > setup (where the database is much bigger than the RAM in the system)? Or > is this not what you are suggesting at all? Yes, keep it that way. The fact that 'random_page_cost >= seq_page_cost' generally means that random reads are more expensive than sequential reads. The actual values are dependent but 4:1 is usually OK, unless your db fits into memory etc. The decrease of performance after descreasing random_page_cost to 3 due to changes of some execution plans (the index scan becomes slightly less expensive than seq scan), but in your case it's a false assumption. So keep it at 4 (you may even try to increase it, just to see if that improves the performance). regards Tomas -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
