Calibration of cost models for managing queries to relational databases

摘要

The development of the cost model used for optimisation of access paths in response to a request to a relational database has a first phase which automatically generates an analytic cost model, and a second phase where the cost model is automatically calibrated.The calibration is based on a record of successive experience of accesses, and a reduced number of automatically generated model verifications. The cost model uses generic formulae applicable to different database systems, and the characteristics of a particular system are described by particular values of the coefficients in the cost formulae.