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MySQL Feed

Oracle MySQL resources, news, and support articles.

Using Go’s auto-reconnecting MySQL client libraries

I’ve been doing a little bit of programming in Go recently, and really enjoying it. It’s an awesome language with really solid libraries. It reminds me a lot of the .NET framework in that it’s well-thought-out, but the Go language itself is a lot smaller, less formal, and a lot more expressive than I ever found C# to be. And that’s saying a lot — C# was my previous favorite language, along with the occasional Java, C++, Python, JavaScript, and — gasp — Visual Basic 6. Go beats them all.

Knowing what pt-online-schema-change will do

pt-online-schema-change is simple to use, but internally it is complex.  Baron’s webinar about pt-online-schema-change hinted at several of the tool’s complexities.  Consequently, users often want to know before making changes what pt-online-schema-change will do when it runs.  The tool has two options to help answer this question: –dry-run and –print.

Swedish MySQL Users Group Meeting

Stockholm will host the Swedish MySQL Users Group on November 21st and the details can be found at

Percona Live London 2012 talks you do not want to miss

Percona Live, London 2012 continues streak of “not to be missed” events in London, following the footsteps of Royal Wedding, Diamond Jubilee and Summer Olympics. We have prepared great set of Tutorials and Sessions for these two day event.

Status versus configuration variables

MySQL’s SHOW STATUS and SHOW VARIABLES commands (or queries against the corresponding INFORMATION_SCHEMA tables) don’t always show what they say. In particular, SHOW STATUS contains several rows that aren’t status-related, but are really configuration variables in my opinion (and it is an opinion — sometimes the difference isn’t black and white).

Here’s a short list of some status counters that I think are really better off as configuration variables:

The average age of metrics being trended

Last night I wrote about trending data with a moving average, and then after I went to bed, I realized I made a mistake on the chart I showed. I calculated α for the exponentially weighted moving average so that the average age of metrics approaches 60 samples as time approaches infinity, and I plotted that on the same chart with a 60-sample simple moving average.

Trending data with a moving average

In my recent talk at Surge and Percona Live about adaptive fault detection (slides), I claimed that hardcoded thresholds for alerting about error conditions are usually best to avoid in favor of dynamic or adaptive thresholds. (I actually went much further than that and said that it’s possible to detect faults with great confidence in many systems like MySQL, without setting any thresholds at all.)

Tungsten Replicator 2.0.6 released - Multi-Master replication made easy and more

Tungsten Replicator version 2.0.6 was released today.

You can get both the binaries and the source code at the project's downloads page.

MySQL and predictive option handling – beware

MySQL command line utilities have an interesting property – if you only use the prefix of the option or command it will go over the list of available command and if there is only one command with matching prefix it will execute it with no warnings or any kind, otherwise it will report the error. For example mysqladmin e works as there is only one command “extended-status” which starts with “e” mysqladmin f however does not work because there are multiple commands which start with “f”.

Overwhelming response from the MySQL community in Barcelona

Within hours of my post about meeting the MySQL community in Barcelona, we got several offers to help, and within one day, an event was created and agreed upon.


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