RAC (Real Application Clusters) Question:

Answer #1
- Cache function is used to show the storage of the information in the clustered network with the Oracle database.

- This uses the database transfer medium and it involves two nodes where one reads the data block from the disk and another write the data to the same disk.

- It provides very good performance and increases the flexibility in terms of execution of the application that is using the platform.

- RAC uses a dedicated server for its network connection and the cache fusion is an internal part to the cluster.

- It uses the same database and keeps the things in the cache till the information is not needed anymore by any other application. It queries the data only when it totally necessary to do it.

- The query from the user always results in the most current version even after the data is being modified.

Answer #2
Using CACHE Fusion, RAC environment logically combines each instance buffer cache to enable nodes to process data as if it resided on a single unit. The RAC SGA is greater than that of the single instance database due to cache fusion. RAC database uses the GCS (Global Cache Service) and GES (Global Enqueuer Service) processes to ensure that all nodes obtain similar blocks to satisfy a query.