Too many connection when extending Phalcon\Db\Adapter\Pdo\Mysql - php

Question

I've attempted to extend the Phalcon\Db\Adapter\Pdo\Mysql to create a log every time a query function returns false.
Even though I'm not creating any new connections except the one in parent::__construct I'm getting the following exception:
Fatal error: Uncaught PDOException: SQLSTATE[08004] [1040] Too many connections in ...Internal/Database/Mysql.php:14 Stack trace: #0 [internal function]: PDO->__construct('mysql:adapter=M...', '...', '...', Array) #1 [internal function]: Phalcon\Db\Adapter\Pdo->connect(Array) #2 .../Internal/Database/Mysql.php(14): Phalcon\Db\Adapter\Pdo->__construct(Array) #3 .../apps/bootstrap/app.php(378): Internal\Database\Mysql->__construct(Array) #4 [internal function]: Closure->{closure}() #5 [internal function]: Phalcon\Di\Service->resolve(NULL, Object(Phalcon\Di\FactoryDefault)) #6 .../apps/bootstrap/core_services.php(7): Phalcon\Di->get('logs') #7 [internal function]: Closure->{closure}() #8 [internal function]: Phalcon\Di\Service->resolve(NULL, Object(Phalcon\Di\FactoryDefault)) #9 .../apps/libs/Internal/Database/Mysql.php(15): Phalcon\Di->get('logger') #10 .../apps/bootstrap/app.php(37 in .../apps/libs/Internal/Database/Mysql.php on line 14
Code:
namespace Internal\Database;
use Phalcon\Db\Adapter\Pdo\Mysql as PhalconMysql;
use Phalcon\Di;
class Mysql extends PhalconMysql
{
public $isLogger = false;
public function __construct(array $descriptor)
{
parent::__construct($descriptor);
$this->oLogger = Di::getDefault()->get('logger');
}
public function query($sqlStatement, $bindParams = null, $bindTypes = null)
{
$oResult = parent::query($sqlStatement, $bindParams, $bindTypes);
if ($oResult === false && $this->isLogger === false) {
$trace = debug_backtrace();
$aCaller = array_shift($trace);
$sFile = $aCaller['file'];
$sLine = $aCaller['line'];
$this->oLogger->error('MySQL query failed. File: ' . $sFile . ', Line: ' . $sLine, ['error' => $this->getErrorInfo()]);
}
return $oResult;
}
}
The line that triggers the error is parent::__construct($descriptor);.
The only other change I've made was to replace the usage of Phalcon\Db\Adapter\Pdo\Mysql with Internal\Database\Mysql. All the connections are created in the same way they were when I were using Phalcon\Db\Adapter\Pdo\Mysql.
I've looked at the parent classes of Phalcon\Db\Adapter\Pdo\Mysql. The only place I see the connection created is here
I'd very much appreciate your help with this issue.

Answer 1

It is not a right thing to extend classes in phalcon, that are actually interacting with other php extensions. Learned it the hard way.
The easy way I would recommend is to override Mvc/Model class as a eg. ModelCommon or BaseModel, and implement there Model::initialize and Model::afterFetch.
But a proper way would to be to use event mechanism developed out in Phalcon. The trick is to attach to beforeQuery and/or afterQuery events.
Shortcut for that, done in DI:
$di->set('db', function() use ($di) {
$config = $di->getConfig();
$connection = new \Phalcon\Db\Adapter\Pdo\Mysql([
// ...
]);
$eventsManager->attach('db', function($event, $connection, $params) use ($config) {
if ($event->getType() == 'beforeQuery') {
// ...
}
if ($event->getType() == 'afterQuery') {
// ...
}
});
$connection->setEventsManager($eventsManager);
return $connection;
});

Answer 2

Looks like the module is trying to connect to database more than once. Perhaps make sure you initialise database service just once in your Module.php

Answer 3

Maybe you can db service as shared when you declare db in $di
$di->setShared('db', function() {
// return your db instance
});

Answer 4

Problem solved, although I still don't understand why it occurred in the first place.
The logger logs to the database, but since it's taken from Di I assumed it reuses existing connection. Removing that line from constructor, and putting it right after the logger is called solved the problem.