Before describing the pdreclaim command, this section describes pages and segments. Pages and segments can be in the statuses shown in the table below.
Table 11-1 Page and segment status
Page and segment status | Description |
---|---|
Unused page | A page that has never been allocated. |
Used free page | A page in which no data is stored because of data deletion.#1 |
Used page | A page that contains data as well as free area to which data can be added. For a table that uses the free space reusage facility, this can include a page to which data cannot be added because it is not yet possible to use free area in the page resulting from data deletion.#1 |
Used full page | A page that stores data and has no free space to which data can be added. For a table or index that does not use the free space reusage facility, this can include a page to which data cannot be added because it is not yet possible to use free area in the page resulting from data deletion.#1 |
Used segment#2 | A segment that contains 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; any other segment is called a segment with available space. Of the segments with available space, a segment whose pages are all empty because of data deletion (used free pages or unused pages) is called a used free segment. |
Unused segment | A segment that has never been used. All tables (or indexes) in RDAREAs can use an unused segment. |
Free segment | A segment that contains no data. Used free segments and unused segments are both free segments. |