Mastering Data Warehouse Aggregates: Solutions for Star Schema Performance

4.4. Specific Solutions

Commercial products that offer aggregate navigation features are numerous. To explore the pros and cons of each would fill the pages of a book this size. And because they are constantly evolving, the book would be out of date almost as soon as it was published. Instead, this chapter has provided the critical skills needed to evaluate a particular solution.

However, there are specific solutions worth a more detailed treatment because they are within reach of most implementations. These approaches are: Oracle's Materialized Views, the Materialized Query Tables of IBM's DB2, and the implementation of aggregates without an aggregate navigator.

Keep in mind that this overview should not be considered the final word regarding specific products. The products will continue to evolve. Instead, consider this overview to be a starting point. As suggested in Chapter 7, implementation of any product, whether discussed here or not, should be informed by a careful evaluation of its capabilities against the requirements that have been developed in this chapter and the priorities of the enterprise.

4.4.1. Living with Materialized Views

The Oracle RDBMS provides aggregate navigation capability through a combination of features, centering on materialized views. The RDBMS's query rewrite capability is aware of the presence of aggregates built using this feature, and uses them as appropriate to rewrite user queries. The RDBMS can also manage the synchronization of materialized ...