protected function unlockAllDocuments($transaction_id)
    {
        $result = $this->getLocksCollection()->deleteMany(array(_LOCKED_FOR_TRANS => $transaction_id), array('w' => 1));

        if(!$result->isAcknowledged()) {
            $this->errorLog(MONGO_LOCK,
                array(
                    'description'=>'Driver::unlockAllDocuments - Failed to unlock documents (transaction_id - ' .$transaction_id .')',
                    'mongoDriverError' => $this->getLastDBError($this->getLocksDatabase()),
                    $result
                )
            );
            throw new \Exception("Failed to unlock documents as part of transaction : ".$transaction_id);
        }
        return true;
    }