This post builds upon the earlier article (Creating a simple Cluster on a single LINUX host) which explained how to install and run a Cluster where all of the nodes run on the same physical host. The single host solution is not great for a real deployment - MySQL Cluster is designed to provide a High Availability (HA) solution by synchronously replicating data between data nodes - if all of the data nodes run on a single host that that machine is a single point of failure. This article demonstrates how to split the nodes between hosts; the configuration will still be fairly simple, using just 2 machines but it should be obvious how to extend it to more.

The MySQL Librarian is a collection of community-generated and cross referenced content related to MySQL. It's a place where the community, collaboratively, builds and maintains MySQL content. This article is the MySQL Librarian manual. If the FAQ are not enough, look here!

Everybody needs sharding, and the Spider storage engine offers a nice solution, transparent to the final user, to implement sharding without losing track of usability.

A tip to kill a long lasting query without losing the current connection.

Refactory.org is "A wiki for useful code snippets", and it has a MySQL section.

The Partition Helper is a Perl script that converts some simple options into lots of partitions. Good for creating partitions on historical data.

Learn how to load a dimension table that contains some attributes that need to be updated (type 1 slowly changing dimension) and some attributes that need to be versioned (type 2 slowly changing dimension) using pure SQL

In this article, you'll learn how to write an information schema plug-in that can access some of the internals of the MySQL server. For this particular purpose, we will focus on a plug-in that reports all the SAVEPOINTs available in the current session. This MYSQL_SAVEPOINTS plug-in may be of some value when debugging scripts and stored routines that rely on complex scenarios using transactions and savepoints.

MySQL 5.1 offers an extremely useful feature called information schema plug-ins. This feature allows dynamic runtime loading of a shared library into the MySQL server to implement a table in the information_schema database. The SQL standard (ISO/IEC 9075-11:2003) allows database implementations to extend the information_schema. MySQL 5.1 transfers the possibility to do this directly to privileged database users so they can extend the information_schema themselves, in any way they see fit. In this article, we will demonstrate how to create a minimal "Hello, World!" MySQL information schema plugin. In a forthcoming article, we'll demonstrate how information schema plugins may be used to report some of the server's internals such as the contents of the query cache, session level objects such as the currently defined TEMPORARY tables, user-defined variables and SAVEPOINTs.

With the User Defined Function (UDF) Interface you can plug your C/C++ functions into the MySQL database server, and call them from your SQL statements just like any other SQL function. You can even use them to create aggregate functions. In this article, you'll learn how to create and run MySQL UDFs on Windows using the Express Edition of the popular Microsoft Visual C++ IDE.

Quite often, people try to solve problems using a cursor. But do you really need one? What is the performance impact of using a cursor anyway? Learn these things and more.

Most people manage to write a single CURSOR loop. But what if you want to nest CURSOR loops? Read this article and learn how.

Cursors are typically traversed using a loop. MySQL syntax to traverse a cursor is quite often misunderstood. This article will learn you how to loop through MySQL cursors.

Learn how to use dynamic SQL using the PREPARE syntax

There is a popular myth about the SQL GROUP BY clause. The myth holds that 'standard SQL' requires columns referenced in the SELECT list of a query to also appear in the GROUP BY clause, unless these columns appear exclusively in an aggregated expression. MySQL is often accused of violating this standard. In this article I will attempt to debunk this myth, and to provide a more balanced view regarding MySQL's treatment of GROUP BY at the same time. To do that, I will first demonstrate that MySQL can be instructed to only accept GROUP BY clauses that include all non-aggregated expressions referred to in the SELECT list, thus making MySQL's behaviour conform more to that of other well-known rdbms-products. Second, I will show that it is very important to clearly define which version of the SQL-standard is being referred to. The two most recent versions use a rather sophisticated way of  []

Communities, their power, and how they work, seen from the inside.

Roland takes the reader through a fascinating path of optimization, explaining many interesting and not immediately evident points

the motivation for the cloud and its democratic technology

The Open SQL Camp 2009, European edition, is hosted at FrOScon 2009

RightScale, the cloud tamer