<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<title>MySQL Native Driver Plugin API</title>
</head>
<body><div class="manualnavbar" style="text-align: center;">
<div class="prev" style="text-align: left; float: left;"><a href="mysqlnd.notes.html">Notes</a></div>
<div class="next" style="text-align: right; float: right;"><a href="mysqlnd.plugin.mysql-proxy.html">A comparison of mysqlnd plugins with MySQL Proxy</a></div>
<div class="up"><a href="book.mysqlnd.html">Mysqlnd</a></div>
<div class="home"><a href="index.html">PHP Manual</a></div>
</div><hr /><div id="mysqlnd.plugin" class="chapter">
<h1>MySQL Native Driver Plugin API</h1>
<h2>Table of Contents</h2><ul class="chunklist chunklist_chapter"><li><a href="mysqlnd.plugin.mysql-proxy.html">A comparison of mysqlnd plugins with MySQL Proxy</a></li><li><a href="mysqlnd.plugin.obtaining.html">Obtaining the mysqlnd plugin API</a></li><li><a href="mysqlnd.plugin.architecture.html">MySQL Native Driver Plugin Architecture</a></li><li><a href="mysqlnd.plugin.api.html">The mysqlnd plugin API</a></li><li><a href="mysqlnd.plugin.developing.html">Getting started building a mysqlnd plugin</a></li></ul>
<p class="para">
The MySQL Native Driver Plugin API is a feature of MySQL Native
Driver, or <em>mysqlnd</em>. <em>Mysqlnd</em>
plugins operate in the layer between PHP applications and the MySQL
server. This is comparable to MySQL Proxy. MySQL Proxy operates on a
layer between any MySQL client application, for example, a PHP
application and, the MySQL server. <em>Mysqlnd</em> plugins
can undertake typical MySQL Proxy tasks such as load balancing,
monitoring and performance optimizations. Due to the different
architecture and location, <em>mysqlnd</em> plugins do not
have some of MySQL Proxy's disadvantages. For example, with plugins,
there is no single point of failure, no dedicated proxy server to
deploy, and no new programming language to learn (Lua).
</p>
<p class="para">
A <em>mysqlnd</em> plugin can be thought of as an extension
to <em>mysqlnd</em>. Plugins can intercept the majority of
<em>mysqlnd</em> functions. The <em>mysqlnd</em>
functions are called by the PHP MySQL extensions such as
<em>ext/mysql</em>, <em>ext/mysqli</em>, and
<em>PDO_MYSQL</em>. As a result, it is possible for a
<em>mysqlnd</em> plugin to intercept all calls made to these
extensions from the client application.
</p>
<p class="para">
Internal <em>mysqlnd</em> function calls can also be
intercepted, or replaced. There are no restrictions on manipulating
<em>mysqlnd</em> internal function tables. It is possible to
set things up so that when certain <em>mysqlnd</em>
functions are called by the extensions that use
<em>mysqlnd</em>, the call is directed to the appropriate
function in the <em>mysqlnd</em> plugin. The ability to
manipulate <em>mysqlnd</em> internal function tables in this
way allows maximum flexibility for plugins.
</p>
<p class="para">
<em>Mysqlnd</em> plugins are in fact PHP Extensions, written
in C, that use the <em>mysqlnd</em> plugin API (which is
built into MySQL Native Driver, <em>mysqlnd</em>). Plugins
can be made 100% transparent to PHP applications. No application
changes are needed because plugins operate on a different layer. The
<em>mysqlnd</em> plugin can be thought of as operating in a
layer below <em>mysqlnd</em>.
</p>
<p class="para">
The following list represents some possible applications of
<em>mysqlnd</em> plugins.
</p>
<ul class="itemizedlist">
<li class="listitem">
<p class="para">
Load Balancing
</p>
<ul class="itemizedlist">
<li class="listitem">
<p class="para">
Read/Write Splitting. An example of this is the PECL/mysqlnd_ms
(Master Slave) extension. This extension splits read/write queries
for a replication setup.
</p>
</li>
<li class="listitem">
<p class="para">
Failover
</p>
</li>
<li class="listitem">
<p class="para">
Round-Robin, least loaded
</p>
</li>
</ul>
</li>
<li class="listitem">
<p class="para">
Monitoring
</p>
<ul class="itemizedlist">
<li class="listitem">
<p class="para">
Query Logging
</p>
</li>
<li class="listitem">
<p class="para">
Query Analysis
</p>
</li>
<li class="listitem">
<p class="para">
Query Auditing. An example of this is the PECL/mysqlnd_sip (SQL
Injection Protection) extension. This extension inspects queries
and executes only those that are allowed according to a ruleset.
</p>
</li>
</ul>
</li>
<li class="listitem">
<p class="para">
Performance
</p>
<ul class="itemizedlist">
<li class="listitem">
<p class="para">
Caching. An example of this is the PECL/mysqlnd_qc (Query Cache)
extension.
</p>
</li>
<li class="listitem">
<p class="para">
Throttling
</p>
</li>
<li class="listitem">
<p class="para">
Sharding. An example of this is the PECL/mysqlnd_mc (Multi
Connect) extension. This extension will attempt to split a SELECT
statement into n-parts, using SELECT ... LIMIT part_1, SELECT
LIMIT part_n. It sends the queries to distinct MySQL servers and
merges the result at the client.
</p>
</li>
</ul>
</li>
</ul>
<p class="para">
<em class="emphasis">MySQL Native Driver Plugins Available</em>
</p>
<p class="para">
There are a number of mysqlnd plugins already available. These
include:
</p>
<ul class="itemizedlist">
<li class="listitem">
<p class="para">
<em class="emphasis">PECL/mysqlnd_mc</em> - Multi Connect
plugin.
</p>
</li>
<li class="listitem">
<p class="para">
<em class="emphasis">PECL/mysqlnd_ms</em> - Master Slave
plugin.
</p>
</li>
<li class="listitem">
<p class="para">
<em class="emphasis">PECL/mysqlnd_qc</em> - Query Cache
plugin.
</p>
</li>
<li class="listitem">
<p class="para">
<em class="emphasis">PECL/mysqlnd_pscache</em> - Prepared
Statement Handle Cache plugin.
</p>
</li>
<li class="listitem">
<p class="para">
<em class="emphasis">PECL/mysqlnd_sip</em> - SQL Injection
Protection plugin.
</p>
</li>
<li class="listitem">
<p class="para">
<em class="emphasis">PECL/mysqlnd_uh</em> - User Handler
plugin.
</p>
</li>
</ul>
</div>
<hr /><div class="manualnavbar" style="text-align: center;">
<div class="prev" style="text-align: left; float: left;"><a href="mysqlnd.notes.html">Notes</a></div>
<div class="next" style="text-align: right; float: right;"><a href="mysqlnd.plugin.mysql-proxy.html">A comparison of mysqlnd plugins with MySQL Proxy</a></div>
<div class="up"><a href="book.mysqlnd.html">Mysqlnd</a></div>
<div class="home"><a href="index.html">PHP Manual</a></div>
</div></body></html>
