Conflict order-based view refreshment scheme for transaction management in data warehouse environment

Abstract

Online analytical processing transactions (OLAP for short) are executed in integrated a data warehouse (DWH for short). DWH should be refreshed by recent value of data in source databases in order to prevent OLAP transactions from reading excessively stale data. This refreshing process is referred to as view maintenance. There have been many researches on ways to guarantee data consistency during the process of view maintenance. The most commonly used approach among them is to execute updated transactions in the nighttime while OLAP transactions are executed only in daytime. It is, however, meaningless to argue about absolute nighttime for a specific corporation. which is globalized. We proposed so called COB algorithm for view maintenance in DWH environment. COB can improve data freshness by supporting concurrent execution of one or more update transactions. COB can, moreover, reduce the cost of space management by maintaining only one additional version during the process of view maintenance.