That Time We Hit a Nasty Surprise in Beta
So, there we were, feeling pretty good about ourselves. We’d just pushed out a new feature to our beta users. This thing was something we’d worked on for ages, and we were all keen to see how folks would take to it. The first few hours? Everything seemed to be running like a dream. We were practically giving each other virtual pats on the back.
Then Things Got… Complicated
And then, the messages started rolling in. “Hey, the app’s totally frozen on me.” “I can’t seem to do anything, it just hangs.” You know, the kind of feedback that makes your heart sink a bit. Initially, we were hoping it was just a couple of isolated incidents, maybe flaky internet connections on their end, that sort of thing. But nope, more and more people started saying the same stuff. The application would just stop responding, doing absolutely nothing. The really odd part was no crashes were showing up in our logs. It was as if the whole system just decided to take an unexpected break.
Digging Into the Problem
One of the more seasoned developers on our team, who’s been around the block a few times, quietly suggested it might be a “deadlock.” That word just kind of stuck with us. A deadlock? To be honest, we hadn’t really put the new module through its paces in terms of handling lots of simultaneous users, especially concerning how it interacted with some of the older bits of our system. It’s a common oversight, really, when you’re under pressure to get something out for beta testing.
So, we decided to get our hands dirty. The first step was to try and make it happen in our own development setup. We quickly put together some scripts to act like a whole bunch of users all trying to use the new feature at exactly the same moment. It took a little while, but then, wham! Our test system locked up solid. We’d caught it!
Alright, so we could reproduce it. The next question was, what exactly was going wrong? We started to peer into what the system was up to, or more accurately, what it wasn’t up to. It sort of boiled down to this:
- One process would grab hold of, let’s call it, Resource X.
- Then, it would try to get its hands on Resource Y.
- At the same time, another process had already got a firm grip on Resource Y.
- And wouldn’t you know it? That second process was waiting patiently to get Resource X.
They were essentially stuck, each waiting for the other to release what it needed. A complete standstill right in our code. Definitely not what we wanted.
The “Oh, Right!” Moment and Sorting It Out
It was one of those moments where you just want to slap your forehead. In our haste to release the beta, we hadn’t paid close enough attention to the sequence in which different parts of our code were requesting these shared resources. Some parts asked for X then Y, while others went for Y then X. When enough users hit the system in just the right way, they’d inevitably cause this tangle.
The actual fix, once we’d identified the core issue, wasn’t overly complex. We basically had to lay down the law: “Okay everyone, from this point forward, if you need both Resource X and Resource Y, you must ask for Resource X first, and then Resource Y. No cutting in line!” We tweaked the code to make sure this rule was followed. We then hammered it with our test scripts again. And, to our relief, the system started playing nice.
What We Took Away from That “Deadlock Beta” Adventure
We rolled out the patched version to our beta users, pretty much crossing our fingers. And then… nothing. The good kind of nothing. The reports of the application freezing up just stopped. You could almost hear the collective sigh of relief from the team.
That whole “deadlock beta” experience was quite the eye-opener for us. It really hammered home the point that even when you’re just in beta, you absolutely cannot afford to skimp on thinking through what happens when many users are active simultaneously. And those tiny details, like the order in which you acquire resources, can come back and cause major headaches. It’s the sort of thing that seems blindingly obvious with the benefit of hindsight, but when you’re deep in the development cycle, it’s surprisingly easy to overlook. We certainly learned that lesson the hard way!
