Single Database Connection in forked PHP Application

Question

My application uses pcntl_fork to fork a childprocess which monitors a connected router. So I instantiate the class ConnectionManager which forks themself into as many childprocesses as machines are needed to be monitored.

I'm using a external DB class which should implement the Singleton pattern but PHP tends to build up a new Database Connection for each forked childprocess.

<?php
/**
 * Database
 * implements Singleton Pattern
 * Returns one static object via Get()
 */
include_once '../config/config.php';
class Database{
    private $log;
    public static $dbLink;
    /**
     * returns the reference to the only possible mysql resource
     * @return unknown
     */
    public static function Get(){
        if(!self::$dbLink){
            $log = Logger::getLogger(__CLASS__);
            self::$dbLink = mysql_connect(DB_HOST, DB_USER, DB_PASSWORD);
            mysql_select_db(DB_SELECT);
            if(!self::$dbLink){
                $log->fatal("Connect to Database failed");
                throw new Exception("Database connection failed: ".mysql_error());
            }
        }
        return self::$dbLink;
    }
        public function Destroy(){
            self::$dbLink = null;
        }
    }


?>

The Problem arises as the number of monitored router increases. Currently we are monitoring around 56 machines, so the application establishes 56 unique mysql_connections to the underlying database. But if the number of machines monitored arises our approach would collide with the mysql_connection_limit.

The Database is used to store the traffic of each router. Additionally each childprocess stores runtime-data which contains e.g. the last retrieve of traffic data or the allowance to run.

My question is, if its possible to use just one Connection. Something like a cache which collects the SQL statements and sends them as query to the database.

But how do I design an approach like mentioned above?

If further information is needed just ask and i'll post some snippets.

Answer 1

As far as I know there is no way to do this in PHP (connection pooling)

You can mysql_pconnect to reuse in the next request. but this may not do what you need.

Otherwise this may be useful to you

https://github.com/junamai2000/mod_namy_pool#readme

"The mysql connection pooling module for a prefork server (like php). You can limit the number of connections by shariing connections bewteern a parent process and child processes"