I strongly believe that active cache invalidation is an anti-pattern, a symptom of bad software architecture. In this post I will sum up the reasons people give for explicit cache purging and explain what’s wrong with them. It is not wrong to allow purging of the cache manually and by exception, but it is wrong when cache invalidating is part of the algorithm. The rule of thumb is: your software should not delete from the cache during normal operation. ...

When building high performance OLTP (online transaction processing) systems you need CPU and IOPS and preferably a whole lot of them. Alternatively you can build a distributed system in the cloud. This will not work (as well) and cloud providers will make you change to this losing strategy one or two magnitudes too fast. That is an awful lot of development time wasted at a moment you are still small and can’t afford to lose any. In this post I will bust the common myths about the cloud and high performance OLTP systems. ...

I have released version 3 of the Symfony Memcache Bundle which is now renamed from “LswMemcacheBundle” to “TqdMemcacheBundle”. I started the bundle to provide mature cache management to Symfony2. It now supports Anti-Dog-Pile, session locking, Doctrine query caching and other important features, such as server pooling support and Windows compatibility. Application level cache in PHP It can be important in a PHP based web application to apply aggressive application level caching. PHP is not a fast language and many web applications use the majority of the time to request, retrieve and transform data they receive from the database. The results of this process are very suitable to be cached in Memcache with a timeout that is specific to the data and it’s use. ...

In order to make your HTML5 games responsive you may choose to create vector graphics in SVG. The commercial Adobe Illustrator and open-source Inkscape software can both be used for this job. I did not like these tools and decided to create my own tool that stays very close to the W3C specification for SVG and allows for high precision editing. Writing SVG by hand Instead of using Inkscape I found myself writing SVG by hand using nothing more than a text-editor and a browser. This was mainly because I did not like the verbose Inkscape output of the SVG and that I had trouble making my vector drawings properly symmetric and properly smooth by having symmetric control points on connecting lines. ...

The videos of PyCon 2016, (that was held a month ago in Portland, Oregon) are online! PyCon is the largest annual gathering for the open-source programming language “Python”. The impressive list of keynote speakers included: Parisa Tabriz (Security Princess), K Lars Lohn (Hippie Biker at Mozilla), Lorena Barba (Computational Scientist), Cris Ewing (Plone Foundation Member), Guido van Rossum (Python’s Creator) and Van Lindberg (Chair of the Python Software Foundation). Free Python videos I think it is amazing that you can watch all these high quality Python talks for free on YouTube. To make it easy for you to choose to pick an interesting talk I made a list of all the videos: ...

13th of July was the last day of GopherCon 2016, the “Largest event in the world dedicated to the Go programming language.” It was held in the Colorado Convention Center in Denver. There are 16 videos online now and 22 lightning talks, so most of the conference is available here. Also interesting are the videos from the previous year and from “dotGo 2015” and the “London Go Gathering 2015” (they may be older, but they are still very relevant). ...

In order to keep Windows running smoothly you need to reinstall it every now and then. In this blog post I’ll explain how you can make a USB drive to perform a clean install. Booting a UEFI machine from USB (without using legacy boot) may be a bit harder than you are used to. Get Windows 10 installation media This is where it is at: https://www.microsoft.com/en-us/software-download/windows10 On Windows the above link allows you to download the “Media Creation Tool”. On Linux on the other hand this allows you to download ISO files of Windows 10. You can use the user-agent switcher to choose either method. Note that the page contents depend on the operating system in the user-agent string and not the browser. ...

Your super-fast laptop comes with Windows 10 installed. That may seem like a waste to you when you are a real Linux geek like me, but it isn’t. You can install your Windows 10 licensed copy in a VirtualBox environment that you run on the host operating system (Linux, what else?). This has the great advantage that you can easily make snapshots of your Windows environment. With snapshots you can easily revert to for instance a “clean install” situation. ...

I confess: I love Flash and I think it is much better than HTML5. But Flash is dead now (I blame Apple) and we have to build in HTML5. Actionscript 3 was a beautiful and powerful language, especially for games. In this post I will describe how to port an application from beautiful Actionscript 3 code (Flash) to the ugly Javascript reality (HTML5). Why Flash was better Drawing graphics in Flash was easy and your drawings could be combined and even easily animated. Flash scaled seamlessly in high quality so that you did not have to bother about screen sizes. There was only one runtime implementation, so there were hardly any compatibility bugs. Animations performed great, even on older computers. It really was a developer dream come true. Now we have to work with Javascript, SVG and all kinds of different browser implementations, a huge step backwards. ...

Linux Mint 18 is released today and I understand why Linux Mint is the world’s most popular Linux distribution (according to DistroWatch). It has all the goodness of Ubuntu 16.04, combined with a user-friendly, familiar and modern looking interface with plenty of options to customize. Cinnamon vs. MATE There is a Cinnamon and a MATE version of Linux Mint 18. I tried them both briefly and I noticed several differences. The MATE version seems more light-weight as it feels a bit more snappy. It sports “Caja” as a file manager which is less powerful than “Nemo”, but still does not feel like it is missing important features. The MATE version has more configuration options than the Cinnamon version. The Cinnamon version on the other hand looks more modern and polished. Your desktop on a cube and wobbly windows, remember that thing? I think it was in 2007 when I have first seen that. It is still supported in MATE, wohoo! ...