Description:
------------
Client compression support was added to mysqlnd in php 5.3.3. PDO_mysql should now be able to use it.

However the constant MYSQL_ATTR_COMPRESS is undefined in the PDO class when compiling using the following (bare minimum) config:

./configure --with-pdo-mysql=mysqlnd --with-mysql=mysqlnd

Due to how recent this addition is, I can find no further information on php.net/google/anywhere...

There are also some confusing (and useless?) switches in configure for mysqlnd compression that seem counter-intuitive.

--disable-mysqlnd-compression-support
                            Enable support for the MySQL compressed protocol in mysqlnd
--with-zlib-dir[=DIR]       mysqlnd: Set the path to libz install prefix

When configure runs, it says that it has disabled mysqlnd compression support, however phpinfo() (post compile) shows that compression is available and that pdo_mysql is using mysqlnd. 

--

mysql

MySQL Support => enabled
Active Persistent Links => 0
Active Links => 0
Client API version => mysqlnd 5.0.7-dev - 091210 - $Revision: 300533 

--

mysqlnd

mysqlnd => enabled
Version => mysqlnd 5.0.7-dev - 091210 - $Revision: 300533 $
Compression => supported
SSL => supported
Command buffer size => 4096
Read buffer size => 32768
Read timeout => 31536000
Collecting statistics => Yes
Collecting memory statistics => No

--

PDO

PDO support => enabled
PDO drivers => sqlite, sqlite2, mysql

pdo_mysql

PDO Driver for MySQL => enabled
Client API version => mysqlnd 5.0.7-dev - 091210 - $Revision: 300533 $



Test script:
---------------
<?php
define("DATABASE_TYPE",	       'mysql');
define("DATABASE_USERNAME",    'dbuser');
define("DATABASE_PORT",	       '3306');
define("DATABASE_HOST",	       'db.server');
define("DATABASE_PASSWORD",    'dbpass');
define("DATABASE_DBNAME",      'dbname');

  try {
    	$o_dbh = new PDO(
    	    DATABASE_TYPE.":host=".DATABASE_HOST.";port=".DATABASE_PORT.";dbname=".DATABASE_DBNAME, 
			DATABASE_USERNAME, 
			DATABASE_PASSWORD,
			Array(
                PDO::MYSQL_ATTR_COMPRESS => true
            )
		);
  } catch (PDOException $o_e) {
     print $o_e->getMessage();
  }

Expected result:
----------------
No output, DB connection established, client compression enabled.

Actual result:
--------------
Error as follows:
Fatal error: Undefined class constant 'MYSQL_ATTR_COMPRESS' in test.php on line 15