Overview
Materialized view logs record the data changes in the base tables of materialized views in a database. Base tables are tables referenced by materialized views. The data changes include all insert, update, and delete operations performed since the last refresh of materialized views. Materialized view logs support incremental refresh of materialized views.
Benefits
Incremental refresh: Based on materialized view logs, the database can apply only the changes that have occurred since the last refresh to the materialized view, without recalculating the data of the entire materialized view. This improves the refresh efficiency, especially in large data sets.
Improved performance: When base tables contain a large amount of data, full refresh of the corresponding materialized view consumes a large amount of computing resources and time. Materialized view logs allow the database to process only the data that has changed since the last refresh, thus significantly improving the efficiency.
Data consistency: Materialized view logs record all data changes even when the materialized view is not refreshed. This can ensure data consistency between the materialized view and base tables in next refresh.