Performance Enhancement Through Replication in an Object-Oriented DBMS

Abstract

In this paper we describe how replicated data can be used to speed up query processing in an object-oriented database system. The general idea is to use replicated data to eliminate some of the functional joins that would otherwise be required for query processing. We refer to our technique for replicating data as field replication because it allows individual data fields to be selectively replicated. In the paper we describe how field replication is specified at the data model level and we present storage-level mechanisms to efficiently support it. We also present an analytical cost model to give some feel for how beneficial field replication can be and the circumstances under which it breaks down. While field replication is a relatively simple notion, the analysis shows that it can provide significant performance gains in many situations. Much of the discussion is based on the EXTRA data model, but the ideas presented here can also be extended to other data models that support reference attributes or referential integrity facilities.