Oracle 5.0 Reference Manual page 2812

• Pooling saves connection time.
• Multiplexed connection: multiple user handles share the same network connection. Once
opened, a network connection is cached and shared among multiple user handles. There is a 1:n
relationship between internal network connection and user connection handles.
• Persistent connection: a network connection is kept open at the end of the web request, if the
PHP deployment model allows. Thus, subsequently web requests can reuse a previously opened
connection. Like other resources, network connections are bound to the scope of a process. Thus,
they can be reused for all web requests served by a process.
20.7.9.2. Limitations
Copyright 1997-2012 the PHP Documentation Group. [2230]
The proof-of-concept does not support unbuffered queries, prepared statements, and asynchronous
queries.
The connection pool is using a combination of the transport method and hostname as keys. As a
consequence, two connections to the same host using the same transport method (TCP/IP, Unix
socket, Windows named pipe) will be linked to the same pooled connection even if username and
password differ. Be aware of the possible security implications.
The proof-of-concept is transaction agnostic. It does not about SQL transactions.
20.7.9.3. About the name mysqlnd_mux
Copyright 1997-2012 the PHP Documentation Group. [2230]
The shortcut
20.7.9.4. Concepts
Copyright 1997-2012 the PHP Documentation Group. [2230]
This explains the architecture and related concepts for this plugin. Reading and understanding these
concepts is required to successfully use this plugin.
20.7.9.4.1. Architecture
Copyright 1997-2012 the PHP Documentation Group. [2230]
The mysqlnd connection multiplexing plugin is implemented as a PHP extension. It is written in C and
operates under the hood of PHP. During the startup of the PHP interpreter, in the module initialization
phase of the PHP engine, it gets registered as a
methods.
The mysqlnd library uses PHP streams to communicate with the MySQL server. PHP streams are
accessed by the mysqlnd library through its net module. The mysqlnd connection multiplexing plugin
proxies methods of the mysqlnd library net module to control opening and closing of network streams.
Upon opening a user connection to MySQL using the appropriate connection functions of either mysqli,
PDO_MYSQL
the pool contains a network connection to the host specified by the connect function using the transport
method requested (TCP/IP, Unix domain socket, Windows named pipe), the pooled connection is
Mysqlnd connection multiplexing plugin (mysqlnd_mux)
Note
Applications must be aware of the consequences of connection sharing
connections.
stands for
mysqlnd_mux
or ext/mysql, the plugin will search its connection pool for an open network connection. If
mysqlnd connection multiplexing
mysqlnd plugin to replace specific mysqlnd C
2792
plugin.