Materialized View

When you want to query a large volume data performance may not satisfy you because of the high cost of query. What should you do in such a situation? One solution is using Materialized View. It is a view which can be refreshed periodically with the frequency you define. You can prepare your query and create a materialized view then in reports or screens you can select results from it just like a table instead of your costly query. What is the advantage? The answer is quite clear: Performance. What is the disadvantage? Results are snapshot of last time of query refresh, so if you need fresh data this may not be the solution.