What’s using all the disk space?
We had an issue a while ago where one of our Mongo instances had run out of available space on the root disk. This was concerning because we use a large separate volume mounted at /data that is dedicated entirely …
So, Patrick, how was your long weekend?
I took this past Monday as a vacation day. Upon returning, I sent this email to the team, and they suggested I post it here.
Upon returning from my vacation day, some of you may ask how my long weekend …
Help! I invented an algorithm and I don’t know how it works!
This past weekend, I needed to find a good fraction to approximate a given value. Along the way, I learned about continued fractions, and emerged with a neat, efficient algorithm. The only trouble is, I can’t figure out why it …
The Case for a Logarithmic Performance Metric
Traditional comparisons of benchmark results focus on percentage differences. While seemingly simple to understand and compute, such comparisons pose a number of problems that are solved by using a different basis for comparison: a logarithmic unit with the rather unfortunate …
Measuring information in millibytes
A thousandth of one byte. Does such a thing even exist?
Yep, it does. I’ve used them before.
How to debug an optimizing compiler
Suppose you work on an optimizing compiler that has a bug, causing the compiled program to …
Fun with DNS
At Vena we’ve been recently engaged in an effort to upgrade our servers to take advantage of AWS’s Autoscaling and Elastic Load Balancing (ELB) services, the ability for servers that are in an unhealthy state to be replaced by new …
Gotcha! Cartesian products of Java 8 streams
Occasionally, you need to compute the Cartesian product of several sets. Java 8 Streams make this simple, clear, elegant… and extravagantly expensive. I’ve created a Cartesian helper class that solves the memory usage problem, and allows Cartesian products to be …
OCaml mimicry in Java
Yaron Minsky from Jane Street gave a great talk on OCaml that serves as a good introduction for someone who is accustomed to Java. In particular, he gives an example for manipulating boolean algebra in just a few lines of …