Book Image

MySQL 5.1 Plugin Development

Book Image

MySQL 5.1 Plugin Development

Overview of this book

MySQL has introduced a Plugin API with its latest version – a robust, powerful, and easy way of extending the server functionality with loadable modules on the fly. But until now anyone wishing to develop a plugin would almost certainly need to dig into the MySQL source code and search the Web for missing bits of the information.This is the first book on the MySQL Plugin API. Written together with one of the Plugin API primary architects, it contains all the details you need to build a plugin. It shows what a plugin should contain and how to compile, install, and package it. Every chapter illustrates the material with thoroughly explained source code examples.Starting from the basic features, common to all plugin types, and the structure of the plugin framework, this book will guide you through the different plugin types, from simple examples to advanced ones. Server monitoring, full-text search in JPEG comments, typo-tolerant searches, getting the list of all user variables, system usage statistics, or a complete storage engine with indexes – these and other plugins are developed in different chapters of this book, demonstrating the power and versatility of the MySQL Plugin API and explaining the intricate details of MySQL Plugin programming.
Table of Contents (16 chapters)
MySQL 5.1 Plugin Development
Credits
About the Authors
About the Reviewer
Preface

Chapter 2. User Defined Functions

Way back in 1998, MySQL 3.21 introduced a framework that allowed users to create new SQL functions easily. It made it possible for developers to write their own functions in C/C++ and load them dynamically into the running server. The functions loaded within this framework were called User Defined Functions or UDFs.

Today not much has changed with UDFs, they are more stable and slightly more secure than they used to be, and they can be declared aggregate for use together with GROUP BY queries. However, many UDFs that worked in 1998 with MySQL 3.21.24 would still work at the time of writing in 2010, with MySQL 5.1.47.

MySQL UDFs are not part of the newer MySQL Plugin API, but there are future plans to make this happen. In the meantime, they can serve as an introduction to MySQL plugins. And sometimes UDFs can be used together with plugins to complement their functionality. In this chapter, we will cover creating User Defined Functions and write several of...