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 the Derby Reference Manual.) 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.

Related concepts
Creating, dropping, and backing up databases