Figure 9-33 shows the operating system is looking even better than before! The CPU utilization dropped from 20% to 7%, and the IO subsystem is receiving virtually no IO requests from Oracle. The status index creation reduced Oracle CPU consumption far more than our anticipated 3%. The index impact was so prolific that it resulted in a 13% CPU consumption reduction. As with the prior tuning cycle, the only way to decrease CPU-related response time is to either use faster CPUs or reduce SQL statement logical IO consumption through tuning or workload balancing.

Figure 9-33. Shown is the operating system analysis information. Because the Oracle load is almost entirely CPU-based, targeting heavy logical IO SQL statements by creating the status column index reduced CPU utilization to 7%. Oracle is submitting virtually no IO requests to the operating system.

The application situation has profoundly changed. Oracle is now processing fewer logical IOs while at the same time executing more SQL statements. This means users are getting more work done but consuming fewer resources! The addition of the status column index had a much larger and positive impact than we anticipated. Clearly, there were other SQL statements that benefited from the index creation. Over the 30-minute interval, we anticipated Oracle CPU consumption would decrease from 1,257 seconds down to 1,027 seconds, but in reality, the consumption decreased to a staggering 344 seconds.