Characteristics of pages that are in error

A page that is in error can be logically or physically in error.

A page is logically in error if its problem can be fixed without redefining new disk tracks or volumes. For example, if Db2 cannot write a page to disk because of a connectivity problem, the page is logically in error. Db2 inserts entries for pages that are logically in error in a logical page list (LPL).

A page is physically in error if physical errors exist, such as device errors. Such errors appear on the write error page range (WEPR). The range has a low and high page, which are the same if only one page has errors.

If the cause of the problem is undetermined, the error is first recorded in the LPL. If recovery from the LPL is unsuccessful, the error is then recorded on the error page range.

Write errors for large object (LOB) table spaces that are defined with LOG NO cause the unit of work to be rolled back. Because the pages are written during normal deferred write processing, they can appear in the LPL and WEPR. The LOB data pages for a LOB table space with the LOG NO attribute are not written to LPL or WEPR. The space map pages are written during normal deferred write processing and can appear in the LPL and WEPR.

A program that tries to read data from a page that is listed on the LPL or WEPR receives an SQLCODE for resource unavailable. To access the page (or pages in the error range), you must first recover the data from the existing database copy and the log.