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.

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MySQL 5.1 Plugin Development
Aug, 2010 | 288 pages
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Table of Contents (16 chapters)
MySQL 5.1 Plugin Development
MySQL 5.1 Plugin Development
Credits
Credits
About the Authors
About the Authors
About the Reviewer
About the Reviewer
Preface
Preface
Free Chapter
1
Compiling and Using MySQL Plugins
Compiling and Using MySQL Plugins
UDF libraries
Plugin libraries
Automatic builds, packaging
Summary
2
User Defined Functions
User Defined Functions
Writing UDFs
A constant integer output UDF
An integer echoing UDF
A simple static text output UDF
A summing aggregate UDF
Further reading
Summary
3
Daemon Plugins
Daemon Plugins
A look inside a Daemon plugin
A Hello World! Daemon plugin
A system and status variables demo plugin
A simple monitoring plugin
System Status Variables plugin
Summary
4
Information Schema Plugins
Information Schema Plugins
Why write Information Schema plugins
The creation of Information Schema plugins
A Static Table example
A System Information plugin
Summary
5
Advanced Information Schema Plugins
Advanced Information Schema Plugins
Accessing MySQL internals
Condition pushdown
A User Variables Information Schema plugin
A Binary Logs Information Schema plugin
Summary
6
Full-text Parser Plugins
Full-text Parser Plugins
The full-text parser plugin architecture
A PHP full-text parser
Summary
7
Practical Full-text Parsers
Practical Full-text Parsers
Boolean parsers
A Boolean full-text parser
An Image Metadata processor
A Soundex full-text parser
Summary
8
Storage Engine Plugins
Storage Engine Plugins
Introducing storage engines
A read-only storage engine
Summary
9
HTML Storage Engine—Reads and Writes
HTML Storage Engine—Reads and Writes
An idea of the HTML engine
Flashback
Creating, opening, and closing the table
Reading data
Updating the table
Optimizing and analyzing
What's left
Compiling and linking
Putting it all together
Summary
10
TOCAB Storage Engine — Implementing Indexes
TOCAB Storage Engine — Implementing Indexes
B-tree library
Storage engine API for indexes
Describing the engine
Creating, opening, and closing the table
Searching in the index
Rows and keys
Table scan and random access
Inserting rows
What's left
Compiling and linking
Putting it all together
Possible extensions
Summary
Beyond MySQL 5.1
Beyond MySQL 5.1
Server services
Audit plugins
Authentication plugins
SQL extension by Storage Engine plugins
Summary

A System Information plugin

In the previous chapter we created a Daemon plugin that exported getrusage() data via status variables. For the sake of the example we will now do the same with the Information Schema table. However, to not repeat ourselves we will go beyond getrusage() and will also use other Linux system information functions. Yes, unfortunately this plugin is unlikely to work on anything except Linux. One can create a portable system information plugin by using, for example, the SIGAR library (http://sigar.hyperic.com) but for simplicity we will keep the example free from external dependencies. 

#include <mysql_priv.h>
#include <sys/sysinfo.h>
bool schema_table_store_record(THD *thd, TABLE *table);

We start the plugin as usual, with the exception of sys/sysinfo.h that we need for system information functions. Then we declare fields; for simplicity we will use a name/value pair, the value being a long long integer:

static ST_FIELD_INFO sys_usage_fields[] =
{
{"RESOURCE...
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