Chapter 6. Querying the Data Warehouse

Introduction

A data warehouse is primarily used to organize data so queries about the business can be answered quickly. As data warehouses grow in size, it is not uncommon to find a fact table several gigabytes or even terabytes in size. In order to obtain fast query response, it is extremely important for the database to retrieve and process such large amounts of data efficiently.

In Chapter 4, we discussed several physical design techniques, including partitioning, compression, and bitmapped indexing, that are suited for data warehouses. In this chapter, we’ll look at query optimizations, such as partition pruning, partition-wise join, and star transformation, that are specifically designed to improve query ...

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