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 5. Advanced Information Schema Plugins

We have seen in the previous chapter how to create a basic Information Schema plugin and then further adapt this knowledge to expose the information about the server operating system. In this chapter we will talk about advanced features of the Information Schema plugins. We will discuss how to access MySQL internal data structures and display them in Information Schema tables, and we will look at condition pushdown optimization.

Accessing MySQL internals

One of the important use cases for the Information Schema plugin is to provide more server diagnostics to the user, that is, to expose the data about the MySQL internals. To do it we need to be able to find and use the internal data structures. Of course MySQL is an open source project and we can see where the data is that we need to capture. Typically, the data we need will be declared in the sql/ directory of the source code, but sometimes they can be in mysys/ or elsewhere.

In order to access...