11.1.1 About free pages

Before describing the pdreclaim command, this section describes pages and segments. Pages and segments can be in the statuses shown in Table 11-1.

Table 11-1 Page and segment status

Page and segment statusDescription
Used pageA page containing table or index data. A page that is filled with data and in which no more data can be stored is called a full page; a page that contains no data due to data deletion is called a used free page.
Unused pageA page that has never been used.
Free pageA page that contains no data. Used free pages and unused pages are both free pages.
Used segment*A segment containing table or index data. A segment that is filled with data and to which no more data can be added is called a full segment; a segment whose pages are all empty due to data deletion (used free pages or unused pages) is called a used free segment.
Unused segmentA segment that has never been used. All tables (or indexes) in RDAREAs can use unused segments.
Free segmentA segment that contains no data. Used free segments and unused segments are both free segments.
* A used segment is available only to the table or index whose data is currently stored in it. No other table or index can use such a segment.