Why is the Unity dash so slow, and why does Canonical not seem to have any interest in speeding it up? Is it faster on their testing machines? Is it significantly faster on new hardware, if you're using an SSD, or if you have more than 4GB of RAM, or something? I quite like Unity generally, but the ridiculous slowness of the dash is a constant irritant.
it's a compiz plugin written in python . python is slow.
The dash itself is written in C++. It gets some of its data from python plugins, but a) not when it's searching for local files or applications, for which it uses services compiled to native code and b) there's no reason python should be slow for stuff that isn't hugely computation intensive like, say, searching a list of filenames. Whatever Unity's problem is, the choice of implementation language is not it.