Re: Allow a per-tablespace effective_io_concurrency setting

On 09/02/2015 02:25 PM, Tomas Vondra wrote:
> 
> As I explained, spindles have very little to do with it - you need
> multiple I/O requests per device, to get the benefit. Sure, the DBAs
> should know how many spindles they have and should be able to determine
> optimal IO depth. But we actually say this in the docs:

My experience with performance tuning is that values above 3 have no
real effect on how queries are executed.

-- 
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com