Database cache requirements calculation using near-line data access traces in a 500+ user transaction system

Abstract

A pragmatic way is shown to calculate database cache sizes for a given desired level of cache performance, without use of application information. Treating applications as black boxes allows focusing on higher order structures of database accesses to classify applications. Online tracing of all database accesses allows a near-line simulation of cache performance for various cache sizes. These simulations result in typical patterns for application groups which point to areas with strong gradients in the relation between cache size and cache efficiency which can be exploited. The near-line-ness of this calculation lends itself to automatic adaptive cache size regulation.