The keyword you want to look for is: SIMD (Single Instruction Multiple Data) optimization at hardware level. This is how many aggregate functions can run real

The keyword you want to look for is: SIMD (Single Instruction Multiple Data) optimization at hardware level. This is how many aggregate functions can run real fast. To take advantage of that, data has to be structured a certain way: In a columnar way (which is then be vectorized and pushed to SIMD).