9.3.13 Reverse Offload Improvements

Minimum software required: 12.1.0.2 BP11

The reverse offload feature enables a storage cell to push some offloaded work back to the database node when the storage cell's CPU is saturated.

Reverse offload from storage servers to database nodes is essential in providing a more uniform usage of all the database and storage CPU resources available in an Exadata environment. In most configurations, there are more database CPUs than storage CPUs, and the ratio may vary depending on the hardware generation and the number of database and cell nodes.

Different queries running at the same time need different rates of reverse offload to perform optimally with regard to elapsed time. Even the same query running in different instances may need different rates of reverse offload.

In this release, a number of heuristic improvements have been added for elapsed time improvement of up to 15% for multiple database instances and different queries running in parallel.