A short time ago I found this very well done podcast: Hanselminutes by Scott Hanselman. In one of the latest episodes he was talking to Jonathan Zuck of ACT Online about Software Licensing. It’s great to get a quick overview about existing licenses and how to best use them. Since this is a huge topic you only get a short overview, but very understandable imho!
Especially interesting was what Jonathan said about the MySQL licensing model, which I had not properly understood all the way until now neither :-). He said since MySQL owns the rights of the software they can decide what license to sell a software under to a customer and

relief them of the burden of a GPL based license, by simply selling it to them …

This article contains my notes and detailed instructions on setting up a MySQL cluster. After reading it, you should have a good understanding of what a MySQL cluster is capable of, how and why it works, and how to set one of these bad boys up. Note that I'm primarily a developer, with an interest in systems administration but I think that every developer should be able to understand and set up a MySQL cluster, at least to make the dev environment more robust.

Notes

• High availability. If one or some of the machines go down, the cluster will stay up, as long as there is at least one copy of all data still present. The more redundant copies of data there are, the more machines you can afford to lose.
• Scalability. Distributed architecture allows for load balancing. If your MySQL …

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The titles of the videos look very much like “must watch”. Found via ThinkPHP, thanks.

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So, I had written a while back: “We currently have a DataMemory of 4GB and IndexMemory of 2GB. Based on the crude methods we have to monitor it, I think we are at about 40% capacity.” Boy, I was wrong.

After that post, I started looking at this more in detail because we were considering buying more RAM “just in case”. I figured out how to use the super secret command “all dump 1000″. The command is not documented in the MySQL documentation that I could find. I did find it in the NDB API documentation before writing this post however. Not sure why I could not find it before.

For those that still don’t know how to use it, simply type “all dump 1000″ from your management console. Then check your cluster log files …

Last year at O’Reilly’s Open Source Conference I hosted a BoF (Birds of a Feather) about memcached.  It was a popular event.  So, this year, I decided to broaden the scope to caching in general.  Its titled Caching for fun and profit.  It will be Wednesday, July 25 from 8:30-9:30pm in Room E141.

Anything goes. We can talk about memcached, Tugela, basic file caching… whatever.

More and more web sites are finding that they need to uses caching to increase their performance. There are those of us that have solved some problems. Others that are new to these techniques have a lot of questions. This BoF is an opportunity for …

So, I mentioned in my MySQL Cluster post that I found out that cluster and joins don’t get a long too well. There are a couple of tips I have for using joins or replacing them with other techniques that I thought I would share.

Here are some things I keep in mind when using the NDB engine. These may apply to the other engines as well.

1. Test using the NDB engine. Testing against another engine is not adequate.
2. Avoid JOIN if you can, test often if you can’t
3. Avoid subqueries always
4. Select using primary keys when at all possible. Always select using a key.
5. Be sure to include both your where and order by columns in your keys.

Try your join from several directions.

Sometimes, the way you join can affect the engine. This is more …