This appendix gives you information that helps you estimate how much memory or disk space is required to store a table and its indexes in memory or on disk.
The formulas given here are not precise, for example, because of the following reasons:
▪solidDB® compresses some data.
▪Variable-length data (for example, VARCHAR) requires different amounts of space, depending upon the actual lengths of the values stored.
▪The in-memory data structures do not necessarily store the same number of pointers for every record.
In the formulas presented here, it is assumed that the data is not compressed, and there are the maximum number of pointers. Thus the results that you get by using these formulas are conservative - that is, the formulas typically overestimate the amount of space required.
In the formulas below, the notation sum_of(x) means to take the sum of the sizes of each x. For example:
▪sum_of(col_size) means to take the sum of the sizes of each of the columns in the table or index.
▪sum_of(index_sizes) means to take the sum of the sizes of all of the indexes on the table.