On Tue, Oct 5, 2010 at 10:33 PM, Thomas Guettler <hv(at)tbz-pariv(dot)de> wrote:
> Hi,
>
> just a guess: Counting is slow, since it needs to check all rows. Explained here:
>
Actually counting was pretty fast. As I said when I created a table
using the subquery that went pretty fast. The update was the slow
part.