Heaps, I/O, and cache strategies

Each Adaptive Server data cache is managed as an MRU/LRU (most recently used/least recently used) chain of buffers. As buffers age in the cache, they move from the MRU end toward the LRU end.

When changed pages in the cache pass a point called the wash marker, on the MRU/LRU chain, Adaptive Server initiates an asynchronous write on any pages that changed while they were in cache. This helps ensure that when the pages reach the LRU end of the cache, they are clean and can be reused.