[Haskell-cafe] Why is my mappend so slow?

[Tom Ellis]

On Fri, Nov 20, 2015 at 10:18:46AM +0100, martin wrote:
> (++) is only used in the Wtrs themselves, but these are only called when I am actually logging something, which is only
> a handful of lines. Adding an mempty Logger does not change the number of lines written but does change the execution
> time. So I don't think this is it.

Surely every call logs *something* even if it's []?