Whitepaper : What Is Index Fragmentation?

When changing data in a database, the database and its indexes become fragmented. As indexes become fragmented, ordered data retrieval becomes less efficient. Inefficient data retrieval reduces the performance of the database. There are several types of fragmentation that can occur. These types of fragmentation impact the performance of the database and the usage of disk space. Logical order and page density issues exist on tables and indexes within databases. Tools for defragmentation at the level of the operating system cannot resolve these issues. The reason is that the fragmentation exists within the files, rather than at the file level itself. This whitepaper describes fragmentation, the different types, how to defragment, how to compact data, and about interleaved indexes.