You had keyboards? Luxury, back in my day we had to stamp punch cards with the tips of our fingers. If we made a mistake, the head operator would cut one of our fingers off with a bread knife. We didn't mind though, it made us tough, that and sleeping in the car park wrapped in tape from old backups just t'stay warm.
You had concrete car parks? When I were a lad, we had to inherit from car park and implement parking spaces ourselves. And if you had an overflow you had to walk -2147483648 miles to work.
I didn't get very far into AoC this year as I ran out of time. Maybe I'll pick it up again later.
But my point is, I was surprised at how hard day 5, part 2 was. I didn't give up and solved it, but went away wondering whey I'd missed something obvious and overcomplicated it. So it brings some relief to know it was 'supposed" to be a bit challenging!
My first thought was that the pilots and crew would lose their jobs if they refused to fly.
But perhaps pilots would be less likely to get rated for Max aircraft if (hypothetically) there's a perceived broad issue with their safety? This could cause those who have a choice (stronger pilots) to go airbus.
I still prefer 200 with an empty list for the 'no results' case. The same client code works, rather than having to code for 204.
- If I query for an identifier which doesn't exist - Server replies 404, this should fall into my error handling as there's a data inconsistency
- If I query say like ?category=automotive&price=1 and I get a 200 containing a json body in which there's an empty list of matches, then my client code can handle 0 matches as well as 1 or 10 with no special handling.
this is the standard we have company-wide and it works pretty well, unless you make a mistake in the uri (like picking up the wrong api version). however, all apis will return some info on their root, so it's easy to distinguish and troubleshoot
I was looking for this comment. I'm very happy with the combo of IntelliJ features and vim movement commands.
The only inertia vim adds to my workflow is escaping into command mode. I have a 'jk' shortcut combo rather than escape, but if I'm hammering away I often mistime it and need to backspace out my jjkk or whatever.
We ran into a problem where we blew the direct memory limit recently.
To trace the problem, I added a breakpoint on ByteBuffer.allocateDirect() - this is how DM is normally allocated. But rather than suspending the process, we set it to print the stacktrace and continue.
This gave us handy output of possible causes. Focusing on the cases which were called from our own code (likely to be the root cause), we found a call to Files.readAllBytes() - which immediately sounds suspicious to cause a memory leak. Indeed this was the culprit, and explained why the problem was sporadic and hard to reproduce (there is some kind of per-thread caching behaviour of direct memory I never did understand properly).
Incidentally, Files.readAllBytes() uses direct memory because it uses an area of memory which both the OS can access (onto which to read the file contents) and which also Java can access (for the application code, rather than copying to the heap, which could be inefficient for large files).
Fortunately, this "by inspection" approach got us to the answer.
Others have stated profiling would work well. We'd have needed a local reproduction of the issue, which wasn't available at the time (could not reproduce without realistic workloads). Otherwise we could have used our SaaS APM software which runs in deployed envs, but that takes a sampling approach and doesn't really dig deep enough for this kind of stuff.
Regression is a good analogy of the problem here. If you found a line of best fit for some datapoints, how would you get back the original datapoints, from the line?
Now imagine terabytes worth of datapoints, and thousands of dimensions rather than two.
Could still happen though unfortunately, as many bought at ultra low interest rates. Those fixes will be coming to an end in a year or two. At least in this country we tend to have fixes of 1-5 years.
