Creating and using a materialized view
You can create a materialized view of a query to calculate and store results of an expensive operation, such as a particular join, on a managed, ACID table that you repeatedly run. When you issue queries specified by that materialized view, the optimizer rewrites the query based on it. This action saves reprocessing. Query performance improves.
In the tasks that follow, you create and populate example tables. The tables are managed tables. You cannot create a materialized view of an external table. You create a materialized view of a join of the tables. Subsequently, you run a query to join the tables, and the query plan takes advantage of the precomputed join to accelerate processing. These over-simplified tasks show the syntax and output of a materialized view, and do not demonstrate accelerated processing that occurs in a real-world task, processing a large amount of data.