The percentage of unused space allocated in a page when a table or index is defined is called the percentage of unused space in a page. When an unused space value is set, the database load utility (pdload) and database reorganization utility (pdrorg) will not normally store data in the specified amount of space.
However, if the database load utility is executed with the -y option specified and no new page can be allocated, it will store data in the specified unused space.
Figure 15-3 shows an overview of unused space in pages.
Figure 15-3 Overview of unused space in pages
To specify the percentage of unused space in a page, use the PCTFREE option of the CREATE TABLE or CREATE INDEX definition SQL statement.
If the set amount of unused space is too small and a row becomes longer as a result of update processing, the number of input/output operations increases because a single row spans multiple pages.