Avoiding Wild Goose Chases While Debugging.

When I’m debugging a complex system, I’m constantly looking for patterns. I just ran this test code... What did I see in the log? I just processed a metric $^&*-load of data, did our memory footprint blip?

I’m probably using every freedom-unit of screen space to tail logs, run a memory usage tool, run an IDE & debugger, watch a trace of API calls, run test code… And I’m doing this over and over. Then I see it. Bingo, that spike in API calls hits only when that process over there jumps to 20% processor usage when the app also throws that error.

Unfortunately, I may have been mistaken. On a sufficiently complex system, the emergent behaviour can approach the appearance of randomness. Combinatorial explosions are for real, and they are happening constantly in your shiny new MacBook.

My bug isn’t what I think it is. I’m examining so many variables in a system with dozens of subsystems at play, it's inevitable I will see a correlation. We know this more formally as the multiple comparisons problem.

We’ve evolved to spot patterns and find paths in a forest of information. Sadly, we can be prone to see problems where only coincidences have occurred.

In this situation, it's easy to follow this fresh lead and spend your next half an hour chasing the new truth. We’ve all done it. Experiment taking a moment in review, try a clean dataset or different tool to falsify your conclusion. If your idea stands up to scrutiny, then the next 30 minutes might not be such a waste of my time.

And if you completely disprove your-self? then relax, you’ve exercised superb technical analysis skills. Get a cup of tea, because you’ve earned it.

It Ain’t What You Don’t Know That Gets You Into Trouble. It’s What You Know for Sure That Just Ain’t So

- (Maybe...) Mark Twain

Comments

What possible use could Gen AI be to me? (Part 1)

There’s a great scene in the Simpsons where the Monorail salesman comes to town and everyone (except Lisa of course) is quickly entranced by Monorail fever… He has an answer for every question and guess what? The Monorail will solve all the problems… somehow. The hype around Generative AI can seem a bit like that, and like Monorail-guy the sales-guy’s assure you Gen AI will solve all your problems - but can be pretty vague on the “how” part of the answer. So I’m going to provide a few short guides into how Generative (& other forms of AI) Artificial Intelligence can help you and your team. I’ll pitch the technical level differently for each one, and we’ll start with something fairly not technical: Custom Chatbots. ChatBots these days have evolved from the crude web sales tools of ten years ago, designed to hoover up leads for the sales team. They can now provide informative answers to questions based on documents or websites. If we take the most famous: Chat GPT 4. If we ignore the

Can Gen-AI understand Payments?

When it comes to rolling out updates to large complex banking systems, things can get messy quickly. Of course, the holy grail is to have each subsystem work well independently and to do some form of Pact or contract testing – reducing the complex and painful integration work. But nonetheless – at some point you are going to need to see if the dog and the pony can do their show together – and its generally better to do that in a way that doesn’t make millions of pounds of transactions fail – in a highly public manner, in production. (This post is based on my recent lightning talk at PyData London ) For the last few years, I’ve worked in the world of high value, real time and cross border payments, And one of the sticking points in bank [software] integration is message generation. A lot of time is spent dreaming up and creating those messages, then maintaining what you have just built. The world of payments runs on messages, these days they are often XML messages – and they can be pa

Is your ChatBot actually using your data?

In 316 AD Emperor Constantine issued a new coin, there's nothing too unique about that in itself. But this coin is significant due to its pagan/roman religious symbols. Why is this odd? Constantine had converted himself, and probably with little consultation - his empire to Christianity, years before. Yet the coin shows the emperor and the (pagan) sun god Sol. Looks Legit! While this seems out of place, to us (1700 years later), it's not entirely surprising. Constantine and his people had followed different, older gods for centuries. The people would have been raised and taught the old pagan stories, and when presented with a new narrative it's not surprising they borrowed from and felt comfortable with both. I've seen much the same behaviour with Large Language Models (LLMs) like ChatGPT. You can provide them with fresh new data, from your own documents, but what's to stop it from listening to its old training instead? You could spend a lot of time collating,

investigating software

Search This Blog