Access patterns, continued
If we pack cells into blocks, the parent-child relationships are induced between the blocks. During the calculation of the aggregations, parents need to be accessed immediately after children or vice versa. This creates certain patterns that the index needs to honor.
Another set of patterns is observed when serving queries. Normally a query corresponds to a grid and if it is followed by a drill-down request, then the grid expands along one of the dimensions.
The index is also expected to take advantage of data distribution (clustering).
The problem of the optimal index choice in this setting has yet to be investigated.