I used K and KDB full-time from around 2003-2005. Very, very good performance, but very steep learning curve and some frustrating bugs, but getting quick direct

I used K and KDB full-time from around 2003-2005. Very, very good performance, but very steep learning curve and some frustrating bugs, but getting quick direct support from Arthur helped a lot (even if his emails were frustratingly terse! ). What else do you expect from a guy whose email address was a@kx.com? It forced me to learn functional programming before it was "in". Once you got the way to think about vectors and functions over vectors you could be very productive chopping up big data in finance. Fun stuff actually.