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

Optimizing and analyzing


In our storage engine, even deleted rows take space, and if the table is regularly updated, it will grow even if the number of rows does not increase. It would be nice to implement OPTIMIZE TABLE so that users could have a simple tool to reclaim the unused space. Luckily, there is a very easy shortcut, we almost do not need to do anything:

int ha_html::optimize(THD* thd, HA_CHECK_OPT* check_opt)
{
return HA_ADMIN_TRY_ALTER;
}

This tells MySQL that for our engine, OPTIMIZE TABLE xxx should be mapped to ALTER TABLE xxx ENGINE=HTML. That is, to optimize our table MySQL will create a new table with the same structure, copy all data over to it, and replace the old table with the new one. Nice, isn't it? Unfortunately, at least in MySQL 5.1.47 there is a bug that will cause our OPTIMIZE TABLE to fail unless our engine can do ANALYZE TABLE too. As a workaround we implement a dummy analyze() that succeeds without actually doing anything:

int ha_html::analyze(THD* thd...