Performance of running sum calculations in SP2

Since I started a series of blogs about AS specific changes in SP2, few people asked me to explain in more details some of the things covered in the SP2 list of changes. The most popular request so far was to explain performance optimizations for running sum calculations. I tried to delay that, because I am writing a article especially about running sums, but I decided not to wait until it is ready for two reasons. First, running sum can mean many different things - there are certainly many techniques how to do it. While I believe in my technique, other people believe in their techniques. Therefore the term "running sum calculations" is somewhat vague. The SP2 change helps some methods, but not the others. Secondly, the actual change in SP2 is in fact much broader then the narrow area of running sums. It's just that it is easiest to demonstrate it using some variation of running sum, but as we will see it helps in many other scenarios as well. Lastly, the article I am writing is getting kind of out of control, and I don't know when (or whether) I will finish it, so instead I can focus on something smaller.

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