Maatkit’s mk-loadavg tool is a helpful way to gather information about infrequent conditions on your database server (or any other server, really). We wrote it at Percona to help with those repeated cases of things like “every two weeks, my database stops processing queries for 30 seconds, but it’s not locked up and during this time there is nothing happening.” That’s pretty much impossible to catch in action, and these conditions can take months to resolve without the aid of good tools.

In this blog post I’ll illustrate a very simple usage of mk-loadavg to help in solving a much smaller problem: find out what is happening on the database server during periods of CPU spikes that happen every so often.

First, set everything up.

1. Start a screen session: …

Maatkit version 3519 is ready for download. There are a lot of changes in this release, many of which are incompatible with previous releases. There are also a lot of important new features. Read on for the details.

First, thanks to everyone who contributed to this month’s release. A lot of people have jumped into Maatkit and started committing code. I attribute this to deliberately forcing a more open policy with decisions being made on the mailing list, rather than the former policy of “Percona pays for development, so they have more say than you do” — a snobby and ill-advised way to treat an open-source project. If you are interested in contributing to Maatkit, please ask. Subversion commit rights are being handed out willy-nilly. It’s great!

Here’s a synopsis of this …

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 [...]

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There’s a new release with a lot of goodies — speed, efficiency, user-friendliness, and new features. In particular some of Percona’s clients have sponsored features for things they need such as the ability to more frequently verify that slaves are in sync with their masters. If you need features, please ask Percona [...]

Rob Young has posted a few blog entries lately on the MySQL Enterprise monitoring software. His latest post claims that agent-based monitoring is equivalent to extensibility (MySQL Enterprise Monitor: Agent = Extensibility).

I think this is conflating two completely distinct properties of a monitoring solution. Cacti is extremely extensible, with a plugin-based architecture and [...]

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Before I tell you what’s new, let me tell you how cool I think it would be if Maatkit were voted Sourceforge.net project of the year. Just something to think about :-) I suggest the “Best Tool or Utility for SysAdmins” category. You can actually click the Back button and nominate it for several categories. Not that anyone would do that, of course.

Also, if anyone wants to jump in and help out with bug fixes and new features, please, by all means. Maatkit is a true open-source project as well as being Free Software. If you can follow coding conventions and understand Perl, I’m a very benevolent dictator and would gladly grant commit rights. As it turns out, since I’ve joined Percona I’m interested in a whole different set of things, …

I just uploaded the 1.0.0 release of my MySQL templates for Cacti. Now there’s an actual download under the Downloads tab. I solved a number of issues in this release. The changelog:

2008-06-01: version 1.0.0

        * Fixed when SHOW MASTER LOGS has no File_size column.
        * Fixed Cacti-version-specific problems with include files.
        * Fixed when binary log is not enabled.
        * Fixed some caching issues.
        * Fixed make-template.pl issues when downloaded from SVN.
        * Replication graph shows only slave_lag instead of Seconds_behind_master
        * Generate a version for Cacti 0.8.6i.
        * Support generating custom versions with make-template.pl.

Cacti, monitoring, …

I finally have some images to show you what my improved Cacti templates look like.

These aren’t a perfect demo, since for example this server doesn’t have the query cache enabled, but it should show you what I’ve done. Note, for example, that each graph is labeled with the actual values of the images drawn on it. You don’t have to guess what the values are by squinting at the graphs.

You can click on any image to go to a larger version. Enjoy:

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Did you notice that I moved this blog from pair Networks to pairLite hosting?

Probably not, unless you check the DNS of xaprb.com regularly!

Don’t you hate it when people say “I’m moving my blog, I hope there won’t be more than a few days of downtime, blah blah…” Why is this ever necessary, I wonder? I wonder the same thing about a lot of hosting providers — recently I had a client in my consulting practice whose (very large, well-known) hosting provider tried to help them with some very simple MySQL work and ended up causing them an obscene amount of downtime, like many many days, and there was no end in sight. As I spoke on the phone with him and asked him about his business, he said “we have X thousand users in our beta.” long pause. “Well, we did …

Yesterday I went to beCamp 2008 along with four roomfuls of other people interested in technology (perhaps close to 100 people total). The conference was a lot of fun. Not everything went as planned, but that was as planned. This was an Open Spaces conference and I thought it worked very well. From an email Eric Pugh sent:

Basically it all boils down to:

Open Space is the Law of Two Feet: if anyone finds themselves in a place where they are neither learning nor contributing they should move to somewhere more productive. And from the law flow four principles:

• Whoever comes are the right people
• Whatever happens is the only thing that could have
• Whenever it starts is the right time
…