Instead of consolidating databases physically or accessing the data where it resides, a data grid places the data into an in-memory middle tier. Like physical federation, the data is being placed into a centralized data repository. Unlike physical federation, the data is not placed into a traditional RDBMS system (Oracle database), but into a high-speed memory-based data grid. Oracle offers both a Java and SQL-based data grid solution. The decision of what product to implement often depends on where the corporations system, database, and application developer skills are strongest. If your organization has strong Java or .Net skills and is more comfortable with application servers than databases, then Oracle Coherence is typically the product of choice. If you have strong database administration and SQL skills, then Oracle TimesTen is probably a better solution.
The Oracle Exalogic solution takes the data grid to another level by placing Oracle Coherence, along with other Oracle...
