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

Condition pushdown


Condition pushdown is not a new kind of wrestling move but a special optimization in the MySQL server. It allows the Storage Engine and Information Schema plugins to use the WHERE condition to filter the rows returned to MySQL, as opposed to letting MySQL process the WHERE condition internally after the rows have been received. So it is effectively pushing down the WHERE condition into the plugin. This optimization is not always meaningful to use. However, if the total number of rows is large, while the number of rows that satisfy the WHERE clause is small, and generating rows is relatively expensive—in such a case this optimization can bring huge performance benefits. For example, the INFORMATION_SCHEMA.COLUMNS table uses it, because it needs to open a table to get the information about its columns, and it is far better to open only one table that the user is interested in, than to open every table in every database, potentially thousands of them.

In these...