15.9.1 Page and segment status

Before reading about reusing used free pages and used free segments in this section, you must be familiar with page statuses and segment statuses. Table 15-4 lists and describes pages statuses, and Table 15-5 lists and describes segment statuses.

Table 15-4 Page statuses

Page statusDescription
Used pageA page in which table or index data is stored. A used page that is completely filled with data such that no more can be added is called a full page, and a used page from which data has been deleted so that it no longer contains data is called a used free page.
Unused pageA page that is not being used.
Free pageA page in which no data is stored. Both used free pages and unused pages are called free pages.

Table 15-5 Segment statuses

Segment statusDescription
Used segment*A segment in which table or index data is stored. A used segment that is completely filled with data such that no more can be added is called a full segment, and a used segment from which data has been deleted so that only free pages remain (used free pages or unused pages) is called a used free segment.
Unused segmentA segment that is not being used. This segment can be used by any table or index in the RDAREA.
Free segmentA segment in which no data is stored. Both used free segments and unused segments are called free segments.
* A used segment can be used only by a table or an index that stored data in it. Other tables or indexes cannot use such a segment.