Operating Systems

You thrive on the adrenalin rush of getting involved in a new performance problem. Hours of investigation and dozens of coffees later, you’ve resolved another problem. Meanwhile, your customers are frustrated and you have wasted CPU.

Take a lesson from the fire department. They don’t want to extinguish fires—they want to prevent fires. Hosing down a house that’s on fire may eventually save the foundation, but the cost is huge compared to avoiding the fire in the first place. Fire detectors are good at this, and likewise, so is performance software. Preventing fires is much cheaper than extinguishing them. This worst practice is often the result of other worst practices, such as not tracking performance and not having a methodology.

Worst Practice #5: Don’t Use a Performance Methodology

Airline pilots use a detailed checklist on every flight. Police officers have a use-of-force specification so they will be consistent in dealing with dangerous situations. Doctors have procedures they follow to determine the root cause of an illness. In fact, there are plenty of capability maturity models that define how to get from poor to best in many areas of life. Although these methodologies have been developed over time using real-world experience, we don’t need them in IT.

Reinventing the wheel is fun and everyone should do it! Or maybe you subscribe to the principle of “not invented here” equals “no good.” Don’t waste time trying to learn from other peoples’ experiences, just keep wasting CPU. There will be another upgrade in a few months. (By the way, methodologies are different from best practices in that a methodology defines the process of how and when to use the best practices.)

Worst Practice #6: Don’t Track Performance

The first question asked when something goes wrong in IT is “what changed?” Specifically, with performance, it might be “so, how fast should it be?” If we don’t know exactly how well module ABC executes when things are good, how will we know when things are bad, and just how bad.

You should be keeping performance statistics on all your major application components (transactions, batch programs, database calls) to use as reference points and develop trends. But who has the time? After all, you have fires to fight!

Worst Practice #7: Have a War-Room Mentality

Go ahead, spend the whole weekend on a conference call with 50 of your colleagues, each of you pointing fingers and getting defensive. You could rely on objective software tools that identify the root cause of the performance issue, but why do that when you could depend on Joe the developer’s gut feel and 30 years of experience? After all, he writes the most complex code you’ve ever seen!

“It’s not my fault” may make you feel good, but what does the war-room mentality cost the company’s bottom line? And did you lose any customers as a result of the extended war-room discussions?

Worst Practice #8: Don’t Tune SQL, Just DB2

DB2 is a huge part of most production systems in IT organizations today. Much time is spent tuning the DB2 subsystem, with all of its buffer pools and DSNZ parms. This is all well and good, but the rubber hits the road when an SQL statement is executed. A poorly written SQL statement can take down a well-tuned DB2 subsystem every time. The DB2 optimizer will try to choose the most efficient path to retrieve the required data, but in many cases, your cowboy coder has made the SQL statement so complicated (showing off his technical skills) that the optimizer just gives up and provides everything contained in the tablespace. Not efficient, but it gets the job done. Tuning SQL may be the biggest opportunity you have to tune your application, but just let the subsystem handle it and it will be alright.

Worst Practice #9: Reinvent the Wheel Yet Again

The mainframe has been around now for 50 years. Much progress has been made in reliability, scalability, security and other important aspects of software development. However, as long as human beings are the ones writing applications, we have to realize the same mistakes will be made over and over again. Who doesn’t start writing a new module by copying Bill’s old code as a template (with all of Bill’s performance defects intact)? Some organizations have developed, after years of experience in the trenches, a best practices guide on how to develop applications with performance in mind. These best practices help new, less experienced programmers avoid making the same mistakes over and over. But your team doesn’t have time to create or teach best practices because they have a deadline to meet! Oops, we’re back to worst practice #1. Oh my. When is that new hardware upgrade going to happen?     

Worst Practice #10: Do Nothing
         
It’s easy to not care about application performance. But it’s not cheap. And your competitors do care.

Now you have 10 worst practices for getting the most you can from your applications. So, go and have some more coffee before your company has to end the free coffee program to help pay for the excess CPU costs.

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