Laravel 5.4 ErrorException: Error while sending STMT_PREPARE packet in queue

I running my application in php laravel 5.4 framework, i used ratchet socket server for real time communication and queue for sending sms & email in between socket connection. sometimes i got an error like below,

ErrorException: Error while sending STMT_PREPARE packet. PID=6779 in /home/username/project/vendor/laravel/framework/src/Illuminate/Database/Connection.php:319

Next Illuminate\Database\QueryException: Error while sending STMT_PREPARE packet. PID=6779 (SQL: select * from jobs where queue = default and ((reserved_at is null and available_at <= 1514718794) or (reserved_at <= 1514718704)) order by id asc limit 1 for update) in /home/username/project/vendor/laravel/framework/src/Illuminate/Database/Connection.php:647

Due this error occurred after that socket server enters into following error

PDOException: SQLSTATE[HY000] [2002] No such file or directory in /home/username/project/vendor/laravel/framework/src/Illuminate/Database/Connectors/Connector.php:68

and socket server stops working due to this problem frequently occurred in production server. kindly help me to solve this issue asap. thank you.

via Chebli Mohamed