Figure 9-29. Shown is the essential application SQL information. Notice there is no physical IO consumed. Compared to Figure 9-23, the top SQL statement's elapsed time per execution improved from 0.632 ms/exec to 0.266 ms/exec, while at the same time, the number of executions during the sample interval increased from 473 to 536.

Figure 9-30 shows logical IO response time decreased to 0.009354 ms/lio from 0.02199 ms/lio (Figure 9-24). Clearly, there was a significant service time change. This means initially Oracle was burning CPU cycles on other tasks besides accessing buffers that already resided in the cache. This is another example of the overhead involved in bringing buffers into Oracle's cache and updating all the related memory structures. As a result of the service time drop, the response-time curve will shift down and to the right, as shown generally in Figure 9-17 and especially in Figure 9-31. This explains why SQL statement elapsed time decreased and utilization decreased, while the workload increased.

Figure 9-30. Shown is the workload diagnostic information. Compared to Figure 9-24, logical IO response time dropped from 0.02119 ms/lio down to a staggering 0.00935 ms/lio. In addition, the overall logical IO workload increased from 69.29 lio/ms to 74.66 lio/ms, representing an 8% increase. So again, performance has improved while the workload has also increased.