Cache of logged queries. This will only be used if the query logger is enabled.
The structure for the logging array is as follows:
array( $logging_key = array( array('query' => '', 'args' => array(), 'caller' => '', 'target' => '', 'time' => 0, 'start' => 0), array('query' => '', 'args' => array(), 'caller' => '', 'target' => '', 'time' => 0, 'start' => 0), ), );
Type: array
protected $queryLog = [];