Non-blocking Creation of Derived Tables

Database systems are used in thousands of applications every day, including online shopping, mobile phone systems and banking. Many of these systems have high availability requirements, allowing the systems to be offline for only a few minutes each year. In existing database systems, user transactions are blocked during materialized view creation and non-trivial database schema transformations. Blocking user transactions is not an option in systems with high availability requirements. A non-blocking method to perform such tasks is therefore needed. In this paper, we present a method for non-blocking creation of derived tables, suitable for highly available databases. These can be used to create materialized views and to transform the database schema. The derived table creation may run as a low priority background process. Thus, the process has little impact on concurrent user transactions.