Years ago, it was common for Oracle's single least recently used (LRU) list to have latching contention issues. LRU lists are used to ensure that the popular buffers remain in the buffer cache and to help server processes quickly locate free and unpopular buffers. The LRU lists are not used to find or locate a specific block; that is the purpose of the cache buffer chains.

One approach that can work well with a single long linked list is to simply divide the list into multiple smaller lists, as illustrated in Figure 3-4. Each of the smaller lists will have its own latch.

Figure 3-4. One approach to implement multiple latches is to divide a large single linked list into multiple smaller linked lists. Oracle did this with the least recently used (LRU) structure.