The database system uses page chains to save liveCache data (C++ objects) and undo log entries and then later access them.
A page chain is a sequence of pages that belong together logically. Each page has exactly one page that follows it. The first page in a page chain is called the root page. The root page contains internal administration information, such as the ID of the last page in the chain.
See also:
Concepts of the Database System, Data Storage and Access