In the past few days it has come to my attention that some people are having problems with Percona's blog at http://www.mysqlperformanceblog.com. I was told that trackbacks seem to be broken and some comments were not showing up.

Anyone else having any problems with what looks like censorship? [edit: trackbacks were a technical error, Dave's comment was trapped in a spam trap. Still looking for people to comment whether or not they're seeing a similar issue, as it's important for people to check to see if their comments are showing up.]

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I am going through all the MySQL Cluster 5.1 DBA exam questions to bring up up to date with the latest release of the software. Part of this is reading all the comments exam candidates have left for a question, looking at what percentage of folks answered it correctly, and then making sure that the questions is still valid.

MySQL Cluster has been rapidly evolving. It used to be impossible to use OPTIMIZE TABLES or create TEMPORARY tables with Cluster. But now both work and these two questions with high pass rates need to be removed.

Oddly some of the lowest percentage correct questions are some of the most generic questions. And these go into the pile to be updated.

The vast majority of the questions on the exam are generic and still are valid today. The goal is to have the exam …

I have a strong professional and personal relationship with Kosovo. Before and after the war, from 1998 to 2002, I was part of the OSCE-UN mission that helped the …

Tomorrow @10 am Central European time we will host the first part of a new series of MySQL for Online Applications - finally!

Registrations and details are here: http://www.mysql.com/news-and-events/web-seminars/online-apps.html

If you are a MySQL and webinar aficionado, you may remember the successful series that we ran in Spring 2007. Two and more years ago it was a great event, with huge participation - it is still available here.

Now we have renewed the material and we have added more hints and information re HA, performance and tuning, online architectures. There is, as usual, some content for developers, for IT managers, for DBAs and for architects. I hope nobody will be disappointed.

This time we …

For one reason or another, many times we find ourselves changing the hostname of a machine. It's been repurposed or moved - or perhaps the original installer didn't know what name it should have. To achieve this on most modern Linux distributions there are 2 key files you need to update.

1. 
   
2. /etc/hostname needs to be updated with correct hostname to be set on boot, and
   
3. /etc/hosts needs to be updated for DNS lookups of the local hostname. This is more important than you might think and will break many applications if not updated.
   

Some people also take the third step of updating the hostname on the fly with the 'hostname' tool, which if you do that means the gotcha I'm about to describe take you completely unaware in some weeks or months.

If you are using MySQL replication, there are two key options which depend on the hostname. These are the 'log-bin' and …

Last weekend, I finally got some time to look around Drizzle. I had already compiled it on my laptop, but hadn't really looked at the code.Then, I thought that looking over some of the blueprints on Launchpad, would be a good way to get familiar with the code base. After a quick search, I found move function/time/ functions into plugin(s)

This blueprint is basically to create UDF plug-ins for the different time related functions. There was no priority assigned and it was on the low hanging fruit milestone. Which was perfect for …

Last Week was busy!

In Seattle we hosted a developer meeting for Drizzle, Memcached, and Gearman.

The highlights for Drizzle?

Aloha Milestone was completed. Last tarball for that release tree has now been posted.

Bell was announced. The major pieces for Bell include a deliverable source tree for distributions, completion of the replication applier, and work on the Performance Schema. More details about Bell can be found here: https://launchpad.net/drizzle/trunk/bell

Cherry. Cherry will be the release after Bell. We will begin to solicit ideas for what should be in that release.

There were a number of lively discussions. …

The SSB scaling numbers trended reasonably well as the system scaled. 

2 -> 4 node scaling and 4->8 node scaling delivered a scalability factor averaging .552 with a range from .512 to .608.   Perfect linear scaling would be .500, i.e. doubling system resources cuts elapsed time in half.

1 -> 2 node scaling averaged .284 (better than linear) due to elimination of physical IO with a larger cache.   Queries ranged from .128 to .499 scalability factor. 

Software is available for trial via our Early Adopter Program at www.calpont.com .

We ran a quick scalability test of Calpont join behavior across using a Star Schema Benchmark data set at a scale factor of 1000. The Star Schema Benchmark transforms a TPC-H / DBT-3 data to a more standardized data warehouse star schema data model, and the 1000 scale factor includes 6 billion rows in the primary fact table. Information on the star schema bench (SSB) can be found at http://www.cs.umb.edu/~xuedchen/research/publications/DataWarehousePerformanceDissertationProposal.pdf .

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-- Note that these queries are run without any tuning or indices created for these joins or filters.
-- Basically, this is just 1) Create tables (without index or …

LINBIT will be a proud sponsor at this year’s LinuxCon in Portland, OR, held on September 21-23. We will also participate in the Linux Plumbers Conference, co-located with LinuxCon.

Phil is to speak at LinuxCon about DRBD 8.3 and beyond. At LPC, we will primarily focus on building highly available storage systems with DRBD, Pacemaker, and the STGT and LIO …