On Thu, Nov 17, 2011 at 11:17 AM, Aidan Van Dyk <aidan@xxxxxxxxxxx> wrote: > But remember, you're doing all that in a single query. So your disk > subsystem might even be able to perform even more *througput* if it > was given many more concurrent request. A big raid10 is really good > at handling multiple concurrent requests. But it's pretty much > impossible to saturate a big raid array with only a single read > stream. The query uses a bitmap heap scan, which means it would benefit from a high effective_io_concurrency. What's your effective_io_concurrency setting? A good place to start setting it is the number of spindles on your array, though I usually use 1.5x that number since it gives me a little more thoughput. You can set it on a query-by-query basis too, so you don't need to change the configuration. If you do, a reload is enough to make PG pick it up, so it's an easy thing to try. -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
