On Mon, Sep 17, 2012 at 1:07 AM, Thomas Guettler <hv(at)tbz-pariv(dot)de> wrote:
> Release 9.2 should increase count(*) performance. Is this wiki page still
> valid?
>
> http://wiki.postgresql.org/**wiki/Slow_Counting<http://wiki.postgresql.org/wiki/Slow_Counting>
>
> Please update the content.
>
> As I understand it, covering indexes don't currently help with count(*)
because indexes can't be traversed in physical order, so it is a matter of
trading random disk I/O for a much larger amount of sequential disk I/O.
Best Wishes,
Chris Travers