In this blog post, we will briefly explore the OS tool strace. It is not widely used due to its performance impacts, and we don’t recommend using it in production. Still, it is amazing at helping you understand some things that happen in MySQL, where the OS is involved, and as a last case resource for troubleshooting.

The strace tool intercepts and records any system calls (a.k.a.  syscalls) performed and any signals received by a traced process. It is excellent for complex troubleshooting, but beware, as it has a high-performance impact for the traced process.

We start our exploration with a simple question: what are the files opened in the OS when you issue FLUSH LOGS in MySQL? We could look at the documentation, but we decided to find out using strace.

For that, we started a MySQL lab instance and …

Next Wednesday, I will present a webinar about MySQL performance profiling tools that every MySQL DBA should know.

Application performance is a key aspect of ensuring a good experience for your end users. But finding and fixing performance bottlenecks is difficult in the complex systems that define today’s web applications. Having a method and knowing how to use the tools available can significantly reduce the amount of time between problems manifesting and fixes being deployed.

In the webinar, titled “Optimizing MySQL Performance: Choosing the Right Tool for the Job,” we’ll start with the basic top, iostat, and vmstat then move onto advanced tools like GDB, Oprofile, and Strace.

I’m looking forward to this webinar and invite you to join us April 16th at 10 a.m. Pacific time. You can learn more and also  …

Most of this stuff is not PHP specific, and Python or Ruby or Java or .NET developers can use the tools in this talk.

The session on joind.in, with user comments/feedback, is at http://joind.in/talk/view/1320.

Slides are at http://talks.php.net/show/confoo10

“My name is Rasmus, I’ve been around for a long time. I’ve been doing this web stuff since 1992/1993.”

“Generally performance is not a PHP problem.” Webservers not config’d, no expire headers on images, no favicon.

Tools: Firefox/Firebug extension called YSlow (developed by yahoo) gives you a grade on your site.

Google has developed the …

I’ve been working with a client recently who has SELinux on his servers.  It has been quite a struggle sometimes.

My colleages tell me that SELinux has a pretty noticeable performance impact.  I am not sure if we have benchmarks to support this; at any rate, the client said it’s OK, we’ll take the performance hit.

There [...]