In-Memory Column Store
When issuing a query to retrieve data from the database, the Oracle query optimizer quickly determines the most efficient way to return the requested information. The “path” to the data consists of accessing the table, or using an index, or a combination of tables and indexes. In this mode, the path entails Oracle reading table blocks from disk into memory in order to access the data. Within the blocks, rows of table data are stored. This method is tried and true and works well.