Magento debugging thoughts

Random thoughts on debugging in magento

Logging magento queries

Sometimes you need to take a look at the queries generated by magento while loading different objects or collections. To log queries edit lib/Varien/Db/Adapter/Pdo/Mysql.php and change the following line:

protected $_debug               = false;

to

protected $_debug               = true;

The log file is specified in:

protected $_debugFile           = 'var/debug/pdo_mysql.log';

Logging ALL magento queries

Even with logging enabled not all queries are  logged. To enable logging all queries change:

protected $_logAllQueries       = false;

to

protected $_logAllQueries       = true;

Logging all magento events

To log all the events magento throws edit app/Mage.php and add the following line to the dispatchEvent function:

Mage::log($name, null, 'events.log');

After the change the function should look something like:

public static function dispatchEvent($name, array $data = array())
    {
        Mage::log($name, null, 'events.log');
        Varien_Profiler::start('DISPATCH EVENT:'.$name);
        $result = self::app()->dispatchEvent($name, $data);
        #$result = self::registry('events')->dispatch($name, $data);
        Varien_Profiler::stop('DISPATCH EVENT:'.$name);
        return $result;
    }

Events will be logged to var/log/events.log