Also note the impact of using mutexes instead of latches. Since a mutex is associated with each library cache object, entire hash chains will not be made unavailable, resulting in a significant reduction in false contention as well as the acquisition CPU consumption, and therefore improved response time.

Now, let's take the conceptual model to a much more realistic level to clarify the library cache object relationships. Three figures are involved in this example. Figure 7-4 is the actual shell script containing the SQL. I simply copied and pasted the code into my Oracle user Linux session. Figure 7-5 is a library cache model with the actual real-life object references. Figure 7-6 shows the relevant parts extracted from the actual trace file.

Figure 7-4. Shown are a few lines of code, which show library cache object relationships. Figure 7-5 is a model of the library cache objects, and Figure 7-6 shows the key parts from the actual trace file.