If you’re familiar with Neil Gunther’s Universal Scalability Law, you may have heard it said that there are two coefficients, variously called alpha and beta or sigma and kappa. There are actually three coefficients, though. See?

No, you don’t see it — but it’s actually there, as a hidden “1″ multiplied by N in the numerator on the right-hand side. When you’re using the USL to model a system’s scalability, you need to use the C(1), the “capacity at one,” as a multiplier. I call this the coefficient of performance. It’s rarely 1; it’s usually thousands.

To illustrate why this matters, consider two systems’ throughput as load increases:

The green line and the blue line are both linearly scalable systems. Add twice the concurrency, get twice the throughput. But the slope of the lines is different. The green system can do three times as much work as the blue system, even though it’s no more …

A common question, especially for a new technology like Galera, is always that people want to know who else is already using the technology. In terms of sales this is often called reference customers. Over the last year we've seen some case studies and press releases regarding business critical Galera option, so I have now collected all of those to our website's User Stories section.

Some highlights of the newly added user stories include:

GuteFrage.net is a German language Question & Answer site and ranks as Germany's 3rd most popular website. They moved to Percona XtraDB Cluster to mitigate operational issues caused by their previous HA solution, and after half a year in production have been happy to see the problems solved.

…

Effective MySQL: Replication Techniques in Depth
Ronald Bradford
Oracle Press
270 pages

Effective MySQL: Replication Techniques in Depth

Ronald Bradford has a way of distilling a great deal of information into eight chapters unlike any otehr author on MySQL. Replication has been one of the more popular features of MySQL, allowing it to blossom into environments ranging from the simplest to the awesomely complex. Usually replication is simple, predictable, and easy to manage. But this book is written for the MySQL DBA on the front lines looking for better, more resilient way of keeping data flowing. This is the latest of a series of books that cover one aspect of MySQL in a concise, no-fluff fashion. But what is …

In the majority of MySQL replication scenarios, you want your slave databases to be a mirror of your master databases. You usually don’t want your slave to be behind your master by more than a few seconds – and your main goal is for your slave to always be in sync with your master. Would you ever want your slave to deliberately be a few seconds, minutes or even hours behind your master? There have been several suggestions from MySQL users over the years regarding this functionality as “feature request” (even though most of the requests were submitted as MySQL “bugs”, which was the easiest way to submit such a request).

The first request (that I could find) was by Jason Garrett, back in August of 2006, and was logged as “bug 21639″. Jason wanted MySQL to “provide a parameter/setting which allows an administrator to specify how many seconds a replication …

This would have to be one of the most common MySQL error messages that is misleading to the end user developer. The MySQL Manual page confirms the broad range of possible conditions, but offers little to a PHP developer that does not speak MySQL Geek. I am commonly asked to help solve this issue from a developer.

The problem is that there are several conditions that can cause this error, and a more meaningful explanation to the end user would help in addressing the issue. In general terms, this actually means “Your SQL statement has failed because the connection to the database has been disconnected because of ???”.

Here are a few common situations and how to check for what “???” is.

1. Your MySQL server really did go away.

We can easily check this by looking at the server uptime and the server error log.

$ …

Start of the year and time for the first speaking tour. This time I will take my MySQL Indexing Best Practices presentation to Charlotte on January 14 and Atlanta on January 15.

I think this presentation is great for Meetup as it is both providing a lot of very good ready to use practical advice on picking MySQL indexes to people only starting to use MySQL, as well as going into the more advanced topics of MySQL index trickery so even advanced MySQL users will find something new to learn. Meetup format should also allow us more time to go into more details and more practical questions when useful. Bring your own indexing war stories if you’re joining us !

Another great thing about indexing topic is this is something both MySQL Developers and MySQL DBAs and Ops people need …

This webinar will examine the benefits of Read-Write splitting. To register, click here.

There are thousands of new online and mobile apps launching every day…but what happens when demand climbs for these apps and databases can’t keep up?  The long-term success of any app hangs on a company’s ability to provide uninterrupted access and availability – translation: Database performance [...] Read More

Now that we are in the New Year, it is time to settle back into work and make plans for 2013. As part of your professional development planning, consider Percona MySQL Training.

Percona will be holding the following MySQL Training classes in the first quarter:

• January
  • Live Virtual Training – DBA Training for MySQL: January 7-10, 2013
  • Chicago, Illinois, USA : January 14-17, 2013
  • London, UK: January 14-17, 2013
• February
  • Frankfurt, DE: February 4-7, 2013
  • San Francisco, CA, USA: February 4-7, 2013
• March
  • New York, NY, USA: March 11-14, 2013

To view these training events, and others, go to percona.com/training.

I should first start this blog post with the acronym IANAL (I am not a lawyer).  Also the views in this post are mine and not my employer's (a lawyer did ask me to say that part).

Questions on the MariaDB JDBC Driver have already been raised so I wanted to do something similar for the MariaDB C Connector.  The JDBC's issues are mostly ethical whereas my C Connector questions are mostly legal.

But first a little history...  MySQL 3.23.58 was the last version to include an LGPL licensed connector for MySQL, the connector went GPL (and of course commercial) after this version.  Nowadays the connector is GPL with a FLOSS exception, that exception allows you to compile with certain other licensed software.  The main reason for this is PHP version 4 switched from a dual-licensed under the …

The WordPress.com stats helper monkeys prepared a 2012 annual report for this blog. Here’s an excerpt: 4,329 films were submitted to the 2012 Cannes Film Festival. This blog had 21,000 views in 2012. If each view were a film, this blog would power 5 Film Festivals Click here to see the complete report.