The issue of risk
Once during one of the projects I was asked what was the risk of something going wrong. I remember I answered that we, programmers, do not assess risks. We just do everything possible to prevent them. “There is no point”, I said, “to calculate the chances and the impact of a file not being in the incoming directory upon the start-up of the process if we can implement a simple check and avoid the disaster”. Needless to say, I was wrong.
Nowadays I work in a bank. And one of the things I learned about banks, they all have departments responsible for managing risks. A bank in its business plays a risky game - it lends money. It is risky because there’s always a possibility that it will not get them back. And banks learnt to manage these risks. They ask: “What can go wrong? What can we do to prevent that? And what can we do to minimize the impact if we won’t manage to prevent it?”
Software industry is much much younger than banking. But we are proud of ourselves, because we use cutting-edge technology and most modern methodologies. Yet, we haven’t learnt some basic principles other industries employ for decades.
We don’t manage risks.
I’ve seen a few projects screw-ups, all for various reasons: a technology chosen wasn’t robust enough to support the solution, the staff’s skills were not strong enough to implement the solutions, requirements were unrealistic… The cause may be different, but the result is always the same - failure, or infinite slippage of the deadline, which is the same as a failure. And in every case the failure seemed to have been unexpected. It puzzled me - why could nobody predict it? And it happens over and over again. A few years ago I was a faithful reader of The Daily WTF blog. Every day it published failure stories like the ones I witnessed. So, if we are so smart, why does it keep happening over and over again?
Because in a software project nobody asks what can go wrong.
Not all risks are the same. Some risks can be assessed and eliminated. Such as a risk that the existing or planned hardware will not be able to manage the workload. This kind of risk is calculable. We can do a stress test, measure the execution time, do basic calculations and determine not only that we need a new server with more powerful CPU, but how exactly powerful it needs to be.
Others are harder to predict. How would you assess a risk of your project manager being a crook and ruining a project?
And, finally, there’s a mother of all risks – a highly improbable event, the Black Swan, as Nassim Nicholas Taleb calls it in his book “The Black Swan: The Impact of the Highly Improbable”. (I would highly recommend it to everyone who wants to learn more about risks) What, for example, is going to happen to your project if all the programmers decide to quit at the same time?
Some time ago I worked on a project that employed so called custom rules engines for performing complex batch calculations on a huge dataset - about a hundred million rows. We had a few thousand rules defined by business people, and in order to get a result we needed to apply every rule to the source dataset. As you can imagine, it was slow. Scanning a hundred million rows is not fast, especially when you need to do it a thousand times. So, a strategic decision was made to speed it up. One of our local geniuses came up with a brilliant, as he thought, idea: instead of applying a thousand rules hundred thousand times each, we will reformat the existing rules so that they form one monstrous rule, containing all thousand, which can be applied to the source dataset in one pass. And so we did. One thing, though, we didn’t take into account: when combined all together, the rules formed a frankensteinian SQL expression more than 1,000,000 character long (that’s right, more than a million). Yes, it worked, and the process became reasonably fast. But what was the price paid?
Imagine that you are a support programmer. You are quite unhappy with your life, and your job in particular, because you’re fed up with those stupid users and their problems. And on one evening, just as you were going to go home, you get a call. Apparently, the rules engine failed. You open the log and what do you see? A million characters long SQL and at an error message the end, saying that an error happened somewhere in there. Yep, somewhere in those million chars. You see, that’s the way Oracle works. It tells you that an error has happened and tells which one (let’s say, division by zero), but doesn’t tell where exactly within the given SQL it has happened. So, what are you going to do, step by step? Don’t know about you, but I would start writing a resignation letter. And I wasn’t the only one confused. No one I asked could answer that question.
You may ask, what does it have to do with risk? There is a direct
We had certain risk that the system being built couldn’t handle the workload. The amount of that risk was known. We could calculate how much time it took to process the data set, extrapolate it to the given requirements and find out that it took 10 times more time than was acceptable. We could resolve it by buying 10 times more powerful server, or cluster of less powerful servers. In any case, the risk and the cost associated with eliminating those risks were calculable.
After a strategic decision was made to solve the performance problem by much more complex rules engine, the risk became incalculable. Yes, they prevented the performance problem, but introduced another and much more serious: in a case of a single failure the system was going to go down for undefined time. Because no one would be able to fix it. And the undefined downtime would mean an unlimited loss for the business, because in a business world time is always money.
So, what they did is substituted an imminent, but assessable risk, that, in fact, could be prevented, with a less probable, but potentially much more severe which that could not be assessed. I don’t believe that solving a minor problem by introducing a much severe one, and hiding a possibility of a failure under the rug is a proper risk management. In the long term it is never a good strategy.