Willem Stuursma

Passionate on product and programming

1. swhiteman 5.6.10 / 7am

   Your reasoning here is largely obsolete; you need to read about the current persistent connection support in mysqli.

   http://php.net/manual/en/mysqli.persistconns.php

   Reply
2. Matthijs 6.4.10 / 9am

   While I agree that manually specifying and using persistant connections is too slim a performance gain to warrant the extra headache, there are alternatives. Apache can handle a connectionpool in a non-obtrusive way – largely negating the mentioned problems.

   Still, it’s one heck of a micro-optimalisation

   Reply
3. Nikhil Mohan 12.17.10 / 8am

   Here’s a nifty little class which will load balance across multiple replicated MySQL server instances, using persistent connections, automatically removing failed MySQL servers from the pool.

   You would ONLY use this for queries, never inserts/updates/deletes, UNLESS you had a multi-master situation where updates to any database serverautomatically replicate to the other servers (I don’t know whether that’s possible with MySQL).

   Using this class, you get a connection to a MySQL server like this:
      
   $con = MySQLConnectionFactory::create();

   Here is the class (you’ll need to customize the $SERVERS array for your configuration — note that you would probably use the same username, password and database for all of the servers, just changing the host name, but you’re not forced to use the same ones):

   <? php
   class MySQLConnectionFactory {
      
   static $SERVERS = array(
      
   array(
           
   ‘host’ => ’myHost1′,
           
   ‘username’ => ’myUsername1′,
           
   ‘password’ => ’myPassword1′,
           
   ‘database’ => ’myDatabase1′),
      
   array(
           
   ‘host’ => ’myHost2′,
           
   ‘username’ => ’myUsername1′,
           
   ‘password’ => ’myPassword2′,
           
   ‘database’ => ’myDatabase2′)
      
   );

      
   public static function create() {
       
   // Figure out which connections are open, automatically opening any connections
      
   // which are failed or not yet opened but can be (re)established.
       
   $cons = array();
      
   for ($i = 0, $n = count(MySQLConnectionFactory::$SERVERS); $i < $n; $i++) {
           
   $server = MySQLConnectionFactory::$SERVERS[$i];
           
   $con = mysql_pconnect($server['host'], $server['username'], $server['password']);
          
   if (!($con === false)) {
          
   if (mysql_select_db($server['database'], $con) === false) {
              
   echo(‘Could not select database: ‘ . mysql_error());
              
   continue;
          
   }
           
   $cons[] = $con;
          
   }
      
   }
       
   // If no servers are responding, throw an exception.
       
   if (count($cons) == 0) {
          
   throw new Exception
           
   (‘Unable to connect to any database servers – last error: ‘ . mysql_error());
      
   }
       
   // Pick a random connection from the list of live connections.
       
   $serverIdx = rand(0, count($cons)-1);
       
   $con = $cons[$serverIdx];
       
   // Return the connection.
       
   return $con;
      
   }
   }
   ?>
   Lightrains Technolabs
    

   Reply

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