Optimal selection of secondary indexes

When planning a database, the problem of index selection is of particular interest. The authors examine a transaction model that includes queries, updates, insertions, and deletions, and they define a function that calculates the transaction's total cost when an index set is used. Their aim is to minimize the function cost in order to identify the optimal set. The algorithms proposed in other studies require an exponential time in the number of attributes in order to solve the problem. The authors propose a heuristic algorithm based on some properties of the cost function that produces an almost optimal set in polynomial time. In many cases, the cost function properties make it possible to prove that the solution obtained is the optimal one.