Oracle Database Tips by Donald Burleson

Top running on a busy system

By default, running top by itself on a command line will show summary statistics for the CPU and memory usage.  In Figure 4.7, the system only has 1.7% idle CPU time, and it has 4,776 kb of free memory (RAM). In this case, the first thing to do is identify what is using 91.3% of the CPU.  top displays the top processes, so first look into the processes with process ID's (PID's) of 7027, 8082 and 8099 as they are the top-3 CPU users. 

In addition to top, sar is another commonly available tool to examine and monitor memory and CPU utilization.  Both are available on many variants of UNIX and merit some attention for a better understanding of these valuable tools.  In order to learn how to benefit from these tools, review their man pages or other documentation. 

Business Tuning

Now before getting confused and starting to think that this is going to be a business process re-engineering book, relax.  While the organization may require a process overhaul to become more efficient, the business tuning referred to here is only in the areas that are interacted with.  It is here, when the 'softer skills' of business knowledge and political skills are needed. 

Business knowledge is needed for many reasons.  First of all, if the business and its processes are understood, it will be possible to quickly identify processes that do not add value to the organization and work to remove them, or at least reschedule them to accommodate more crucial work better.   

When the cause of a system performance problem has been isolated and a solid understanding of the business exists, it will be easier to answer the question, "Is this query or report really necessary?"  Another reason that knowledge of the business is beneficial is that when tuning SQL or making recommendations for application revisions, knowing how the users use the information will be invaluable when determining things like whether a bitmap index will help performance or hurt it.

Political skills are important when it comes to presenting findings to management.  Knowing when to fight for a recommendation and when to accept a compromise solution will help keep management happy. It also has the potential benefit of providing credibility so next time an issue arises where a compromise will not provide the performance that the business requires, the recommendations will be taken seriously.

The last piece of business tuning to mention is that the key to a well performing database lies not in having the best tuning scripts, the best GUI tuning tool, the best database initialization parameters, the best operating system kernel settings or even the best tuning book.  The key to an optimized database lies in having a database and application that were designed with the intended use in mind.  All the tuning books, tips, seminars, scripts and tools are reactive when compared to an application that was built with a solid understanding of what the business needed the tool for, and how they wanted to use it. 

The above book excerpt is from:

Oracle Wait Event Tuning

High Performance with Wait Event Iinterface Analysis 

ISBN 0-9745993-7-9  

Stephen Andert 

http://www.rampant-books.com/book_2004_2_wait_tuning.htm