# Database pages

Derby tables and indexes, known as conglomerates, consist of two or more pages.

A page is a unit of storage whose size is configurable on a system-wide, database-wide, or conglomerate-specific basis. By default, a conglomerate grows one page at a time until eight pages of user data (or nine pages of total disk use, which includes one page of internal information) have been allocated. (You can configure this behavior; see "derby.storage.initialPages" in Tuning Java DB.) After that, it grows eight pages at a time.

The size of a row or column is not limited by the page size. Rows or columns that are longer than the table's page size are automatically wrapped to overflow pages.

Parent topic: A Derby database
Related concepts
Creating, dropping, and backing up databases