CODS: Evolving Data Efficiently and Scalably in Column Oriented Databases
Database evolution is the process of updating the schema of a database or data warehouse (schema evolution) and evolving the data to the updated schema (data evolution). Database evolution is often necessitated in relational databases due to the changes of data or workload, the suboptimal initial schema design, or the availability of new knowledge of the database. It involves two steps: updating the database schema, and evolving the data to the new schema. Despite the capability of commercial RDBMSs to well optimize query processing, evolving the data during a database evolution through SQL queries is shown to be prohibitively costly.