Archive for April, 2026

“How many Kafka events will Flink process per second?”

Saturday, April 11th, 2026

I’m often asked this. The specific question varies, but it’s typically some variation of asking how quickly a single CPU of Flink processes events from a Kafka topic.

Why “per CPU”? Maybe because enterprise software is typically charged per CPU? Maybe because I tend to talk to people who run everything in Kubernetes, who think of running software in terms of requests / limits? Not sure, but the question tends to be framed from the perspective of asking how much processing they can expect to get from a CPU.

I try to avoid doing the engineer thing of answering “it depends“… but… it really does depend!

That is the motivation behind this post: to give me something I can point at as an illustration of the degree to which Flink’s performance varies (and a taste of the range of interrelated factors that influence it).

(more…)

Paying for image hosting

Monday, April 6th, 2026

I don’t take my blog very seriously. It’s a place where I leave myself reminders of things I figured out how to do, or share things I’ve done that won’t fit in a tweet Bluesky post. But even so, I get annoyed that my blog has often been offline.

My site’s host provider has a monthly bandwidth limit. When I hit that limit, my site is taken offline, replaced with an error page saying that I’ve exceeded my quota.

I’ll write a blog post that includes images, and if too many people look at the page too many times, the whole site goes offline for the rest of the month. (To be fair, it’s never a single post that does that – I don’t get that many hits! More often it’s when I’ve written a few posts in a month, and the last one pushes me over the line). Normally I end up offline for just a day a two, but it has been over a week before.

Last month, I finally decided to do something about it. I started looking at moving the images I use in blog posts somewhere else that wouldn’t count against my bandwidth limit. My blog isn’t serious enough for me to be willing to spend a lot on it, but I don’t mind paying something to make the worry about image bandwidth go away.

I searched for image hosting services, and started reading about services such as postimages.org ($14.99 a month), imgbb.com ($12.99 a month), sirv ($19 a month), and imagekit.io ($9 a month). Every service I found felt too limited, too expensive, or both.

(more…)

Another break in Devon

Saturday, April 4th, 2026

Like last year, we went to Devon for a week before Easter. And like last year, I used it as a chance to walk, forget work, and catch up on books, games, and movies.

I played…

I read…

I watched…

(more…)