The touch count reset value when a buffer header is promoted. Consistent read and segment header blocks are exempt.

The touch count reset value when a buffer header crosses from the hot region into the cold region. Decreasing this will make it more difficult for a buffer header to be promoted.

Write lists, commonly called dirty lists or LRU-W lists, are composed entirely of dirty buffer headers. Each of the dirty buffer headers is also in the CBC structure. Oracle has the concept of a working set, which consists of an LRU latch, an LRU chain, and a write list. Each database writer is associated with one or more working sets. Upon instance startup, Oracle will determine the number of working sets and the number of database writers (init.ora db_writer_processes, which has a default of 1), and then set their association. When a database writer writes, it feeds off one of its write lists. Both server processes and database writers move unpopular dirty buffer headers from their LRU chains to their associated write lists. Now let's inject some movement into these facts.