Table fragmentation can impede performance. When rows are not stored contiguously, or if rows are split into more than one page, performance decreases because these rows require additional page accesses.

When an update to a row causes it to grow beyond the original space allocated for it, the row is split and the initial row location contains a pointer to another page where the entire row is stored. As more rows are stored on separate pages, more time is required to access the additional pages.

Use the Defragment button to defragment rows in a table or the Compress button to defragment the indexes which have become sparse due to deletions.

The reorganization may also reduce the total number of pages used to store the table and its indexes, and it may reduce the number of levels in an index tree.

Note that the reorganization does not result in a reduction of the total size of the database file. The Rebuild button on the General tab completely rebuilds the database, eliminating any fragmentation and free space. This option may result in a reduction of the total size of the database files.