The data for each table is stored in a file on disk. Tables consist of pages with a size that you define when you create the table. For example, you can specify a page size of 2 KB, 4 KB, and so forth by powers of two up to 64 KB. Each page has a certain amount of overhead, which depends on the page size. Relevant values and how they are calculated for each possible page size are described in Space Requirements for Tables on page 395.

Each page stores a number of rows. The number of rows per page varies, according to the row width, the storage structure of the table, whether or not the table is compressed, and how much data has been added or deleted because the table was last modified.

The page is an important concept in understanding query performance because it affects the amount of disk I/O a query does, as well as the amount of CPU resources required to read through a table.