title: PDO class not found fatal error after upgrading to php 5.3.x
body: <p>We had a server upgrade where we moved form 5.2.x to php 5.3.x. I was mysql pdo with the code showen below which was working before the upgrade.</p>
  
  <pre><code>    &lt;?php
  
  error_reporting(E_ALL);
  ini_set('display_errors', '1');
  
  
  /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
   * Database user / pass
   */
  $sql_details = array(
      "user" =&gt; "",
      "pass" =&gt; "",
      "host" =&gt; "",
      "db" =&gt; ""
  );
  
  
  // This is included for the development and deploy environment used on the DataTables
  // server. You can delete this block - it just includes my own user/pass without making 
  // them public!
  if ( is_file($_SERVER['DOCUMENT_ROOT']."/datatables/pdo.php") ) {
      include( $_SERVER['DOCUMENT_ROOT']."/datatables/pdo.php" );
  }
  // /End development include
  
  
  /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
   * Database connection
   */
  
  /* PDO connection */
  $db = new PDO(
      "mysql:host={$sql_details['host']};dbname={$sql_details['db']}",
      $sql_details['user'],
      $sql_details['pass'],
      array(
          PDO::ATTR_ERRMODE =&gt; PDO::ERRMODE_EXCEPTION
      )
  );
  
  /* mysql_* connection */
  /*
  if ( ! $db = mysql_pconnect( $sql_details['host'], $sql_details['user'], $sql_details['pass'] ) ) {
      header( $_SERVER['SERVER_PROTOCOL'] .' 500 Internal Server Error' );
      die( 'Could not open connection to server' );
  }
  
  if ( ! mysql_select_db( $sql_details['db'], $db ) ) {
      header( $_SERVER['SERVER_PROTOCOL'] .' 500 Internal Server Error' );
      die( 'Could not select database' );
  }
  */
  </code></pre>
  
  <p>But after the upgrade, i get a fatal error that PDO class not found. I check ht php.ini and pdo is enabled. Below is the snippet from php.ini.</p>
  
  <pre><code>'--with-mysql=/usr' '--with-mysql-sock=/var/lib/mysql/mysql.sock' '--with-mysqli=/usr/bin/mysql_config' '--with-openssl=/usr' '--with-openssl-dir=/usr' '--with-pcre-regex=/opt/pcre' '--with-pdo-mysql=shared' '--with-pdo-sqlite=shared' '--with-pic' '--with-png-dir=/usr' '--with-sqlite=shared' '--with-xpm-dir=/usr' '--with-zlib' '--with-zlib-dir=/usr'
  pdo_mysql
  pdo_mysql.default_socket =&gt; /var/lib/mysql/mysql.sock =&gt; /var/lib/mysql/mysql.sock
  pdo_sqlite
  </code></pre>
  
  <p>Could you please help me with whats the problem here?</p>
  
  <p>Thanks in advance,
  Srini.</p>