This completes the three Oracle internals chapters! The next chapter begins a journey into understanding what kind of impact we can expect from our proposed performance-increasing solutions.

2 Simply issuing a commit command when no object change occurred will not trigger the log writer to write. This is easy to test. Create a tight PL/SQL loop containing two lines: a commit and a 1-second sleep. Let this run while operating system tracing the log writer background process. You will not see the log writer issue a write request. However, if you add a third line into the tight PL/SQL loop that performs some type of subsecond DML loop, after 60 seconds, you will see the log writer issue about 60 write calls.

3 Details about these experiments are documented in an OraPub technical paper. Search for "global temp" on the OraPub web site.