diff --git a/lib/classes/connection.php b/lib/classes/connection.php
index 4e0bb707d4..9e62310f4c 100644
--- a/lib/classes/connection.php
+++ b/lib/classes/connection.php
@@ -12,174 +12,66 @@
 use Alchemy\Phrasea\Application;
 
 /**
- *
- * @license     http://opensource.org/licenses/gpl-3.0 GPLv3
- * @link        www.phraseanet.com
+ * Pool of PDO connections to phraseanet databoxes and appbox;
  */
 class connection
 {
-    /**
-     *
-     * @var Array
-     */
-    private static $_PDO_instance = array();
+    private static $_PDO_instances = array();
+    private static $_self;
 
-    /**
-     *
-     * @var boolean
-     */
-    private static $_selfinstance;
-
-    /**
-     *
-     * @var Array
-     */
-    public static $log = array();
-    protected $app;
-
-    public function __construct(Application $app)
-    {
-        $this->app = $app;
-    }
-
-    /**
-     *
-     */
-    public function __destruct()
-    {
-        self::printLog($this->app);
-
-        return;
-    }
-
-    /**
-     *
-     * @return Void
-     */
-    public static function printLog(Application $app)
-    {
-        if (!$app['debug']) {
-            return;
-        }
-
-        $totalTime = 0;
-
-        foreach (self::$log as $entry) {
-            $query = $entry['query'];
-            do {
-                $query = str_replace(array("\n", "  "), " ", $query);
-            } while ($query != str_replace(array("\n", "  "), " ", $query));
-
-            $totalTime += $entry['time'];
-            $string = $entry['time'] . "\t" . ' - ' . $query . ' - ' . "\n";
-            file_put_contents(__DIR__ . '/../../logs/mysql_log.log', $string, FILE_APPEND);
-        }
-        $string = count(self::$log) . ' queries - ' . $totalTime
-            . "\nEND OF QUERY " . $_SERVER['PHP_SELF']
-            . "?";
-        foreach ($_GET as $key => $value) {
-            $string .= $key . ' = ' . $value . ' & ';
-        }
-        $string .= "\nPOST datas :\n ";
-        foreach ($_POST as $key => $value) {
-            $string .= "\t\t" . $key . ' = ' . (is_scalar($value) ? $value : 'non-scalar value') . "\n";
-        }
-        $string .= "\n\n\n\n";
-
-        file_put_contents(__DIR__ . '/../../logs/mysql_log.log', $string, FILE_APPEND);
-
-        return;
-    }
-
-    /**
-     *
-     * @return type
-     */
-    protected static function instantiate(Application $app)
-    {
-        if (!self::$_selfinstance)
-            self::$_selfinstance = new self($app);
-
-        return;
-    }
-
-    /**
-     *
-     * @param Application $app
-     * @param string      $name
-     *
-     * @return connection_pdo
-     */
     public static function getPDOConnection(Application $app, $name = null)
     {
-        self::instantiate($app);
-        if (trim($name) == '') {
-            $name = 'appbox';
-        } elseif (is_int((int) $name)) {
-            $name = (int) $name;
-        } else {
+        if (!self::$_self) {
+            self::$_self = new self();
+        }
+        if (null !== $name && !is_numeric($name)) {
             return false;
         }
-
-        if (!isset(self::$_PDO_instance[$name])) {
-            $hostname = $port = $user = $password = $dbname = false;
-
-            $connection_params = array();
-
-            if (trim($name) !== 'appbox') {
-                $connection_params = phrasea::sbas_params($app);
-            } else {
-                $connexion = $app['phraseanet.configuration']['main']['database'];
-
-                $hostname = $connexion['host'];
-                $port = $connexion['port'];
-                $user = $connexion['user'];
-                $password = $connexion['password'];
-                $dbname = $connexion['dbname'];
-            }
-
-            if (isset($connection_params[$name])) {
-                $hostname = $connection_params[$name]['host'];
-                $port = $connection_params[$name]['port'];
-                $user = $connection_params[$name]['user'];
-                $password = $connection_params[$name]['pwd'];
-                $dbname = $connection_params[$name]['dbname'];
-            }
-
-            try {
-                self::$_PDO_instance[$name] = new connection_pdo($name, $hostname, $port, $user, $password, $dbname, array(), $app['debug']);
-            } catch (\Exception $e) {
-                throw new Exception('Connection not available');
-            }
-        }
-        if (array_key_exists($name, self::$_PDO_instance)) {
-            return self::$_PDO_instance[$name];
+        if (null === $name) {
+            $name = 'appbox';
+        } else {
+            $name = (int) $name;
         }
 
-        throw new Exception('Connection not available');
+        if (isset(self::$_PDO_instances[$name]) && self::$_PDO_instances[$name] instanceof \connection_pdo) {
+            return self::$_PDO_instances[$name];
+        }
+
+        $hostname = $port = $user = $password = $databaseName = false;
+
+        if (trim($name) !== 'appbox') {
+            $params = phrasea::sbas_params($app);
+            if (!isset($params[$name])) {
+                throw new \Exception(sprintf('Unknown connection parameters for databox "%s"', $name));
+            }
+            $hostname = $params[$name]['host'];
+            $port = $params[$name]['port'];
+            $user = $params[$name]['user'];
+            $password = $params[$name]['pwd'];
+            $databaseName = $params[$name]['dbname'];
+        } else {
+            $params = $app['phraseanet.configuration']['main']['database'];
+
+            $hostname = $params['host'];
+            $port = $params['port'];
+            $user = $params['user'];
+            $password = $params['password'];
+            $databaseName = $params['dbname'];
+        }
+
+        try {
+            return self::$_PDO_instances[$name] = new \connection_pdo($name, $hostname, $port, $user, $password, $databaseName, array(), $app['debug']);
+        } catch (\Exception $e) {
+            throw new \Exception('Connection not available', 0, $e);
+        }
     }
 
-    /**
-     *
-     * @param  type $name
-     * @return type
-     */
-    public static function close_PDO_connection($name)
+    public function __destruct()
     {
-        if (isset(self::$_PDO_instance[$name])) {
-            self::$_PDO_instance[$name]->disconnect();
-            self::$_PDO_instance[$name] = null;
-            unset(self::$_PDO_instance[$name]);
-        }
-
-        return;
-    }
-
-    public static function close_connections()
-    {
-        foreach (self::$_PDO_instance as $name => $conn) {
-            self::close_PDO_connection($name);
+        foreach (self::$_PDO_instances as $conn) {
+            $conn->close();
         }
+        self::$_PDO_instances = array();
 
         return;
     }
diff --git a/lib/classes/connection/abstract.php b/lib/classes/connection/abstract.php
index 9af46eb344..26acddd415 100644
--- a/lib/classes/connection/abstract.php
+++ b/lib/classes/connection/abstract.php
@@ -9,18 +9,16 @@
  * file that was distributed with this source code.
  */
 
-/**
- *
- *
- * @license     http://opensource.org/licenses/gpl-3.0 GPLv3
- * @link        www.phraseanet.com
- */
 abstract class connection_abstract
 {
-    protected $name;
+    protected $name = null;
+    protected $dsn = null;
     protected $credentials = array();
     protected $multi_db = true;
-    protected $connection;
+    protected $connection = null;
+
+    abstract public function close();
+    abstract public function connect();
 
     public function get_credentials()
     {
@@ -32,10 +30,6 @@ abstract class connection_abstract
         return $this->multi_db;
     }
 
-    /**
-     *
-     * @return string
-     */
     public function get_name()
     {
         return $this->name;
@@ -43,29 +37,35 @@ abstract class connection_abstract
 
     public function ping()
     {
-        if (null === $this->connection) {
-            $this->initConn();
+        if (false === $this->is_connected()) {
+            return false;
         }
 
         try {
             $this->connection->query('SELECT 1');
-        } catch (PDOException $e) {
+        } catch (\PDOException $e) {
             return false;
         }
 
         return true;
     }
 
-    /**
-     *
-     * @return string
-     */
     public function server_info()
     {
-        if (null === $this->connection) {
-            $this->initConn();
+        if (false === $this->ping()) {
+            throw new \Exception('Mysql server is not reachable');
         }
 
         return $this->connection->getAttribute(constant("PDO::ATTR_SERVER_VERSION"));
     }
+
+    public function __destruct()
+    {
+        $this->close();
+    }
+
+    protected function is_connected()
+    {
+        return $this->connection !== null;
+    }
 }
diff --git a/lib/classes/connection/interface.php b/lib/classes/connection/interface.php
index d30a407bc5..caa1d3229d 100644
--- a/lib/classes/connection/interface.php
+++ b/lib/classes/connection/interface.php
@@ -9,12 +9,6 @@
  * file that was distributed with this source code.
  */
 
-/**
- *
- *
- * @license     http://opensource.org/licenses/gpl-3.0 GPLv3
- * @link        www.phraseanet.com
- */
 interface connection_interface
 {
     public function ping();
diff --git a/lib/classes/connection/pdo.php b/lib/classes/connection/pdo.php
index e4651fc053..e70ed5206e 100644
--- a/lib/classes/connection/pdo.php
+++ b/lib/classes/connection/pdo.php
@@ -9,134 +9,163 @@
  * file that was distributed with this source code.
  */
 
-/**
- *
- * @package     connection
- * @license     http://opensource.org/licenses/gpl-3.0 GPLv3
- * @link        www.phraseanet.com
- */
 class connection_pdo extends connection_abstract implements connection_interface
 {
     protected $debug;
+    protected $retryFrequency = 2;
+    protected $retryNumber = 1;
 
-    /**
-     *
-     * @param string  $name
-     * @param string  $hostname
-     * @param int     $port
-     * @param string  $user
-     * @param string  $passwd
-     * @param string  $dbname
-     * @param array   $options
-     * @param Boolean $debug
-     *
-     * @return connection_pdo
-     */
-    public function __construct($name, $hostname, $port, $user, $passwd, $dbname = false, $options = array(), $debug = false)
+    public function __construct($name, $hostname, $port, $user, $password, $databaseName = false, $options = array(), $debug = false)
     {
         $this->debug = $debug;
         $this->name = $name;
-
         $this->credentials['hostname'] = $hostname;
         $this->credentials['port'] = $port;
         $this->credentials['user'] = $user;
-        $this->credentials['password'] = $passwd;
+        $this->credentials['password'] = $password;
+        if ($databaseName) {
+            $this->credentials['dbname'] = $databaseName;
+        }
 
-        if ($dbname)
-            $this->credentials['dbname'] = $dbname;
+        $this->dsn = $this->buildDataSourceName($hostname, $port, $databaseName);
 
-        $this->initConn();
+        $this->connect();
 
         return $this;
     }
 
-    protected function initConn()
+    public function setRetryNumber($retryNumber)
     {
-        $this->connection = null;
-
-        if (isset($this->credentials['dbname']))
-            $dsn = 'mysql:dbname=' . $this->credentials['dbname'] . ';host=' . $this->credentials['hostname'] . ';port=' . $this->credentials['port'] . ';';
-        else
-            $dsn = 'mysql:host=' . $this->credentials['hostname'] . ';port=' . $this->credentials['port'] . ';';
-
-        $this->connection = new \PDO($dsn, $this->credentials['user'], $this->credentials['password'], array());
-
-        $this->connection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
-        $this->connection->exec("
-            SET character_set_results = 'utf8', character_set_client = 'utf8',
-            character_set_connection = 'utf8', character_set_database = 'utf8',
-            character_set_server = 'utf8'");
+        $this->retryNumber = $retryNumber;
     }
 
-    /**
-     *
-     * @return void
-     */
-    public function disconnect()
+    public function setRetryFrequency($retryFrequency)
     {
-        $this->connection = null;
+        $this->retryFrequency = $retryFrequency;
+    }
+
+    public function connect()
+    {
+        // already connected do not reconnect
+        if ($this->ping()) {
+            return;
+        }
+
+        // if disconnected close connection
+        $this->close();
+
+        $tries = $this->retryNumber;
+        $infiniteMode = $this->retryNumber <= 0;
+        $lastException = null;
+
+        do {
+            if (!$infiniteMode) {
+                $tries--;
+            }
+            try {
+                $this->init();
+            } catch (\PDOException $e) {
+                $this->connection = null;
+                $lastException = $e;
+
+                // wait only if there is at least one try remaining or in infinite mode
+                // && connection has not been initialized
+                if ($infiniteMode || (!$infiniteMode && $tries !== 0)) {
+                    sleep($this->retryFrequency);
+                }
+            }
+        } while (!$this->is_connected() && ($infiniteMode || (!$infiniteMode && $tries > 0)));
+
+        if (!$this->is_connected()) {
+            throw new Exception(sprintf('Failed to connect to "%s" database', $this->dsn), 0, $lastException);
+        }
     }
 
-    /**
-     *
-     * @return void
-     */
     public function close()
     {
-        connection::close_PDO_connection($this->name);
+        $this->connection = null;
     }
 
     public function __call($method, $args)
     {
-        if (null === $this->connection) {
-            $this->initConn();
+        if (false === $this->is_connected()) {
+            throw new \LogicException('No connection available');
         }
 
         if (!method_exists($this->connection, $method)) {
             throw new \BadMethodCallException(sprintf('Method %s does not exist', $method));
         }
 
-        $tries = 0;
-
-        do {
-            $tries++;
-            try {
-                set_error_handler(function ($errno, $errstr) {
-                    if (false !== strpos($errstr, 'Error while sending QUERY packet')) {
-                        throw new \Exception('MySQL server has gone away');
-                    }
-                    throw new \Exception($errstr);
-                });
-
-                if ('prepare' === $method && $this->debug) {
-                    $ret = new connection_pdoStatementDebugger(call_user_func_array(array($this->connection, $method), $args));
-                } else {
-                    $ret = call_user_func_array(array($this->connection, $method), $args);
+        try {
+            set_error_handler(function ($errno, $errstr) {
+                if (false !== strpos($errstr, 'Error while sending QUERY packet')) {
+                    throw new \Exception('MySQL server has gone away');
                 }
-                restore_error_handler();
+                throw new \Exception($errstr);
+            });
 
-                return $ret;
-            } catch (\Exception $e) {
-                restore_error_handler();
+            $returnValue = $this->doMethodCall($method, $args);
 
-                $found = (false !== strpos($e->getMessage(), 'MySQL server has gone away')) || (false !== strpos($e->getMessage(), 'errno=32 Broken pipe'));
-                if ($tries >= 2 || !$found) {
-                    throw $e;
-                }
-                $this->initConn();
+            restore_error_handler();
+
+            return $returnValue;
+        } catch (\Exception $e) {
+            restore_error_handler();
+
+            $unreachable = (false !== strpos($e->getMessage(), 'MySQL server has gone away')) || (false !== strpos($e->getMessage(), 'errno=32 Broken pipe'));
+            if (!$unreachable) {
+                throw $e;
             }
-        } while (true);
+
+            $this->connect();
+        }
+
+        return $this->doMethodCall($method, $args);
     }
 
-    /**
-     *
-     * @param  string         $message
-     * @return connection_pdo
-     */
-    protected function log($message)
+    protected function init()
     {
-        file_put_contents(__DIR__ . '/../../../logs/sql_log.log', $message . "\n", FILE_APPEND);
+        if ($this->is_connected()) {
+            return;
+        }
 
-        return $this;
+        $this->connection = new \PDO($this->dsn, $this->credentials['user'], $this->credentials['password'], array());
+
+        $this->connection->setAttribute(\PDO::ATTR_ERRMODE, \PDO::ERRMODE_EXCEPTION);
+        $this->connection->exec("
+            SET character_set_results = 'utf8', character_set_client = 'utf8',
+            character_set_connection = 'utf8', character_set_database = 'utf8',
+            character_set_server = 'utf8'
+        ");
+    }
+
+    private function doMethodCall($method, $args)
+    {
+        if ('prepare' === $method) {
+            $pdoStatement = call_user_func_array(array($this->connection, $method), $args);
+
+            $statement = new connection_pdoStatement($pdoStatement);
+
+            // decorate statement with reconnectable statement
+            $statement = new connection_pdoStatementReconnectable($statement, $this);
+
+            if ($this->debug) {
+                // decorate reconnectable statement with debugger one
+                $statement = new connection_pdoStatementDebugger($statement);
+            }
+
+           return $statement;
+        }
+
+        return call_user_func_array(array($this->connection, $method), $args);
+    }
+
+    private function buildDataSourceName($host, $port, $databaseName = null)
+    {
+        if (isset($databaseName)) {
+            return sprintf('mysql:dbname=%s;host=%s;port=%s;', $databaseName, $host, $port);
+        }
+
+        return sprintf('host=%s;port=%s;', $host, $port);
     }
 }
diff --git a/lib/classes/connection/pdoStatement.php b/lib/classes/connection/pdoStatement.php
new file mode 100644
index 0000000000..7386c54837
--- /dev/null
+++ b/lib/classes/connection/pdoStatement.php
@@ -0,0 +1,37 @@
+<?php
+
+/*
+ * This file is part of Phraseanet
+ *
+ * (c) 2005-2014 Alchemy
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+class connection_pdoStatement implements \connection_statement
+{
+    protected $statement;
+
+    public function __construct(\PDOStatement $statement)
+    {
+        $this->statement = $statement;
+
+        return $this;
+    }
+
+    public function getQueryString()
+    {
+        return $this->statement->queryString;
+    }
+
+    public function execute($params = array())
+    {
+        return $this->statement->execute($params);
+    }
+
+    public function __call($function_name, $parameters)
+    {
+        return call_user_func_array(array($this->statement, $function_name), $parameters);
+    }
+}
diff --git a/lib/classes/connection/pdoStatementDebugger.php b/lib/classes/connection/pdoStatementDebugger.php
index 8a71dcbacf..ef66f2417e 100644
--- a/lib/classes/connection/pdoStatementDebugger.php
+++ b/lib/classes/connection/pdoStatementDebugger.php
@@ -9,26 +9,27 @@
  * file that was distributed with this source code.
  */
 
-/**
- *
- * @license     http://opensource.org/licenses/gpl-3.0 GPLv3
- * @link        www.phraseanet.com
- */
-class connection_pdoStatementDebugger
-{
-    /**
-     *
-     * @var PDOStatement
-     */
-    protected $statement;
+use Monolog\Logger;
+use Monolog\Handler\StreamHandler;
 
-    public function __construct(PDOStatement $statement)
+class connection_pdoStatementDebugger implements connection_statement
+{
+    protected $statement;
+    protected $logger;
+
+    public function __construct(\connection_statement $statement, Logger $logger = null)
     {
         $this->statement = $statement;
+        $this->logger = $logger ?: new Logger('sql-query', [new StreamHandler(__DIR__ . '/../../../logs/mysql_log.log')]);
 
         return $this;
     }
 
+    public function getQueryString()
+    {
+        return $this->statement->getQueryString();
+    }
+
     public function execute($params = array())
     {
         $start = microtime(true);
@@ -38,13 +39,17 @@ class connection_pdoStatementDebugger
         } catch (\Exception $e) {
             $exception = $e;
         }
-        $time = microtime(true) - $start;
-        connection::$log[] = array(
-            'query' => '' . str_replace(array_keys($params), array_values($params), $this->statement->queryString),
-            'time'  => $time
-        );
-        if ($exception instanceof Exception)
+
+        $this->logger->addInfo(sprintf(
+            '%s sec - %s - %s',
+            round(microtime(true) - $start, 4),
+            $exception !== null ? 'ERROR QUERY' : 'OK QUERY',
+            str_replace(array_keys($params), array_values($params), $this->getQueryString())
+        ));
+
+        if ($exception instanceof \Exception) {
             throw $exception;
+        }
 
         return $result;
     }
diff --git a/lib/classes/connection/pdoStatementReconnectable.php b/lib/classes/connection/pdoStatementReconnectable.php
new file mode 100644
index 0000000000..4216d55af1
--- /dev/null
+++ b/lib/classes/connection/pdoStatementReconnectable.php
@@ -0,0 +1,52 @@
+<?php
+
+/*
+ * This file is part of Phraseanet
+ *
+ * (c) 2005-2014 Alchemy
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+class connection_pdoStatementReconnectable implements \connection_statement
+{
+    protected $queryString;
+    protected $statement;
+    protected $conn;
+
+    public function __construct(\connection_statement $statement, \connection_pdo $conn)
+    {
+        $this->statement = $statement;
+        $this->conn = $conn;
+
+        return $this;
+    }
+
+    public function getQueryString()
+    {
+        return $this->statement->getQueryString();
+    }
+
+    public function execute($params = array())
+    {
+        try {
+            return $this->statement->execute($params);
+        } catch (\Exception $e) {
+            $unreachable = ($e->getCode() === 2006) || (false !== strpos($e->getMessage(), 'MySQL server has gone away')) || (false !== strpos($e->getMessage(), 'errno=32 Broken pipe'));
+            if (!$unreachable) {
+                throw $e;
+            }
+            $this->conn->connect();
+        }
+        // retry query with update statement
+        $this->statement = $this->conn->prepare($this->getQueryString());
+
+        return $this->statement->execute($params);
+    }
+
+    public function __call($function_name, $parameters)
+    {
+        return call_user_func_array(array($this->statement, $function_name), $parameters);
+    }
+}
diff --git a/lib/classes/connection/statement.php b/lib/classes/connection/statement.php
new file mode 100644
index 0000000000..12317cf259
--- /dev/null
+++ b/lib/classes/connection/statement.php
@@ -0,0 +1,16 @@
+<?php
+
+/*
+ * This file is part of Phraseanet
+ *
+ * (c) 2005-2014 Alchemy
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+interface connection_statement
+{
+    public function execute($params = array());
+    public function getQueryString();
+}
diff --git a/lib/classes/record/adapter.php b/lib/classes/record/adapter.php
index 436ff78250..54ed198901 100644
--- a/lib/classes/record/adapter.php
+++ b/lib/classes/record/adapter.php
@@ -1652,6 +1652,7 @@ class record_adapter implements record_Interface, cache_cacheableInterface
             $pathdest = $this->generateSubdefPathname($subdef, $app['filesystem'], $pathdest);
 
             $app['task-manager.logger']->addInfo(sprintf('Generating subdef %s to %s', $subdefname, $pathdest));
+
             $this->generate_subdef($app['media-alchemyst'], $subdef, $pathdest, $app['task-manager.logger']);
 
             if (file_exists($pathdest)) {
diff --git a/tests/Alchemy/Tests/Phrasea/Setup/InstallerTest.php b/tests/Alchemy/Tests/Phrasea/Setup/InstallerTest.php
index 717ed61f7b..579b629c04 100644
--- a/tests/Alchemy/Tests/Phrasea/Setup/InstallerTest.php
+++ b/tests/Alchemy/Tests/Phrasea/Setup/InstallerTest.php
@@ -15,19 +15,16 @@ class InstallerTest extends \PHPUnit_Framework_TestCase
     public function setUp()
     {
         parent::setUp();
-        \connection::close_connections();
     }
 
     public function tearDown()
     {
-        \connection::close_connections();
         parent::tearDown();
     }
 
     public static function tearDownAfterClass()
     {
         $app = new Application('test');
-        \connection::close_connections();
         \phrasea::reset_sbasDatas($app['phraseanet.appbox']);
         \phrasea::reset_baseDatas($app['phraseanet.appbox']);
         parent::tearDownAfterClass();
diff --git a/tests/classes/PhraseanetPHPUnitAbstract.php b/tests/classes/PhraseanetPHPUnitAbstract.php
index e0c14d859b..f8fa38c3fc 100644
--- a/tests/classes/PhraseanetPHPUnitAbstract.php
+++ b/tests/classes/PhraseanetPHPUnitAbstract.php
@@ -106,8 +106,6 @@ abstract class PhraseanetPHPUnitAbstract extends WebTestCase
 
         parent::setUp();
 
-        connection::close_connections();
-
         error_reporting(-1);
 
         \PHPUnit_Framework_Error_Warning::$enabled = true;
diff --git a/tests/classes/connectionTest.php b/tests/classes/connectionTest.php
index 1c4cf74e5d..aadf2733ea 100644
--- a/tests/classes/connectionTest.php
+++ b/tests/classes/connectionTest.php
@@ -8,6 +8,6 @@ class connectionTest extends \PhraseanetPHPUnitAbstract
         $conn->exec('SET @@local.wait_timeout= 1');
         usleep(1200000);
         $conn->exec('SHOW DATABASES');
-        connection::close_connections();
+        $conn->close();
     }
 }