How delays are communicated is more important than the delay itself

Last month I had a few unfortunate experiences where deadlines were missed and a lot of extra work was spend on what was perceived as a simple and easy task. Of course it is never fun to miss a deadline and have to spend extra time (and money). But these things happen, it is and remains ‘just’ an estimate. There is always some uncertainty and risk at play.

And don’t forget Hofstadter’s law:

It always takes longer than you expect, even when you take into account Hofstadter's Law.

So that an estimate is wrong doesn’t bother me too much and can be expected.

Sidenote: Delays are part of life, if you are a regular user of the Belgian public transport system you should know.

What I didn’t like was that no communication was done and I only learned a few weeks later that we would miss our deadline. If the delay was communicated well ahead of time it wouldn’t be a big deal. At that time we could have discussed with business what to do. Could we push the deadline, involve extra developers, reduce the scope of a feature, …?

However by waiting to communicate to just before the deadline, it only lead to frustration, escalation(where I got involved) and this blog post 😄.

The lesson to learn here is:

How and when the delay is communicated matters far more than the delay itself.

And now stop reading and go back to work before you miss your next deadline!

Podman– Command execution failed with exit code 125

After updating WSL on one of the developer machines, Podman failed to work. When we took a look through Podman Desktop, we noticed that Podman had stopped running and returned the following error message: Error: Command execution failed with exit code 125 Here are the steps we tried to fix the issue: We started by running podman info to get some extra details on what could be wrong: >podman info OS: windows/amd64 provider: wsl version: 5.3.1 Cannot connect to Podman. Please verify your connection to the Linux system using `podman system connection list`, or try `podman machine init` and `podman machine start` to manage a new Linux VM Error: unable to connect to Podman socket: failed to connect: dial tcp 127.0.0.1:2655: connectex: No connection could be made because the target machine actively refused it. That makes sense as the podman VM was not running. Let’s check the VM: >podman machine list NAME ...

Cache stampede: when our cache turned against us

While investigating some performance issues, we ran into an ASP.NET Core API that cached a fairly expensive aggregation query for 60 seconds. Under normal load, that was fine: one request rebuilds the cache, everyone else reads from it. Under peak load, dozens of requests would arrive in that same expiry window, all see a cache miss, and all fire the same expensive query in parallel. The database didn't like that. That was the moment when our caching layer stopped helping and started hurting. A burst of requests comes in at the same time, all miss the cache, and all go hammer the database or the downstream API at once. That's a cache stampede . The cache was supposed to protect our backend, and for a few hundred milliseconds it did the opposite. Why this happens IMemoryCache.GetOrCreate (and its async sibling) looks like it protects you, but it doesn't add any locking on its own. Look at the naive version: public async Task<Report> GetReportAsync(string key) ...

A complex system designed from scratch never works

A few years ago, I worked as an architect on a big mainframe rewrite. I still count it as one of my failures. Not because the technology was wrong, but because I couldn't convince the management team to simplify the approach. Years later, the organization is still struggling to get the new system up and running. I left the project at the time, because I couldn't put my name behind an approach that would take very long and cost a lot of money without a working system to show for it along the way. Gall’s Law That memory keeps coming back to me, because it's a textbook case of Gall's Law playing out in real life. Gall's Law , from John Gall's Systemantics , states it plainly: A complex system that works is invariably found to have evolved from a simple system that worked. A complex system designed from scratch never works, and it cannot be patched to make it work. You have to start over with a simple system that works. What does that mean in practice,...

The art of simplicity

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