A performance analysis of view materialization strategies

The conventional way to process commands for relational views is to use query modification to translate the commands into ones on the base relations. An alternative approach has been proposed recently, whereby materialized copies of views are kept, and incrementally updated immediately after each modification of the database. A related scheme exists, in which update of materialized views is deferred until just before data is retrieved from the view. A performance analysis is presented comparing the cost of query modification, immediate view maintenance, and deferred view maintenance. Three different models of the structure of views are given a simple selection and projection of one relation, the natural join of two relations, and an aggregate (e.g. the sum of values in a column) over a selection-projection view. The results show that the choice of the most efficient view maintenance method depends heavily on the structure of the database, the view definition, and the type of query and update activity present.