To improve Oracle performance, you must of course
understand the technology of each response time component that
contributes significantly to your targeted user action’s response time.
The place you should begin your research is the Oracle
Database Concepts guide at http://technet.oracle.com. The response time components
that show up in your resource profiles associate directly to
instrumented Oracle kernel actions described in the
Concepts guide. For example, it describes how the
Oracle LGWR process copies content from the redo log buffer to an online
redo log file. An Oracle kernel process accounts for the time it spends
waiting on LGWR to perform this particular action with the wait event
log file sync.
There are lots of other such events. The number of wait events inside the Oracle kernel has grown with each new release, as shown in Table 11-1. Thankfully, it is not important for you to know a lot of details about every Oracle wait event. You usually don’t need the gory details in your brain for any more than a couple of wait events at a time—the ones that are dominating your targeted user action at the moment. This is excellent news, because some of the events require some study time to understand. Rather than learn and try to retain a lot of details about dozens of events, I think it is more important to focus on the following:
Know how to target the events that are important to you right now. I describe how to do this in Part ...