System and method to maintain coherence of cache contents in a multi-tier software system aimed at interfacing large databases

摘要

A method and a system for maintaining coherence of cache contents in a multi-tiered architecture of servers are described. This includes a front tier of satellite servers, each operating a local cache, and a middle tier of central servers each operating a central cache. Central servers interface with databases through database servers to retrieve the data elements used to construct objects and store them in central caches. Once constructed, objects are attributed a time-to-live (TTL) and stored in central caches then forwarded to the satellite servers where they are stored in local caches before being delivered to the software applications that have requested them. They are invalidated when outdated and reconstructed from a central server from where they are forwarded to all central caches and to the local caches where they are needed.