Research and Advances

Approximating block accesses in database organizations

When data records are grouped into blocks in secondary storage, it is frequently necessary to estimate the number of blocks XD accessed for a given query. In a recent paper [1], Cardenas gave the expression XD = m(1 - (1 - 1/m)k), (1) assuming that there are n records divided into m blocks and that the k records satisfying the query are distributed uniformly among the m blocks. The derivation of the expression was left to the reader as an exercise.

Advertisement

Author Archives

Shape the Future of Computing

ACM encourages its members to take a direct hand in shaping the future of the association. There are more ways than ever to get involved.

Get Involved