Materialized View Logs

A materialized view log is a table at the materialized view's master site or master materialized view site that records all of the DML changes to the master table or master materialized view. A materialized view log is associated with a single master table or master materialized view, and each of those has only one materialized view log, regardless of how many materialized views refresh from the master. A fast refresh of a materialized view is possible only if the materialized view's master has a materialized view log. When a materialized view is fast refreshed, entries in the materialized view's associated materialized view log that have appeared since the materialized view was last refreshed are applied to the materialized view.