PHP Fatal error: Uncaught PDOException: SQLSTATE[HY000] [1040] Too many connections in OJS 3.2.0-3

Hi,
I see a lot of repeating fatal errors on the php error logs like;

[01-Jun-2020 04:21:00 Europe/Istanbul] PHP Fatal error:  Uncaught PDOException: SQLSTATE[HY000] [1040] Too many connections in /home/journals/public_html/lib/pkp/lib/vendor/illuminate/database/Connectors/Connector.php:70
Stack trace:
#0 /home/journals/public_html/lib/pkp/lib/vendor/illuminate/database/Connectors/Connector.php(70): PDO->__construct('mysql:host=loca...', 'databasename', '......', Array)
#1 /home/journals/public_html/lib/pkp/lib/vendor/illuminate/database/Connectors/Connector.php(46): Illuminate\Database\Connectors\Connector->createPdoConnection('mysql:host=loca...', 'databasename', '......', Array)
#2 /home/journals/public_html/lib/pkp/lib/vendor/illuminate/database/Connectors/MySqlConnector.php(24): Illuminate\Database\Connectors\Connector->createConnection('mysql:host=loca...', Array, Array)
#3 /home/journals/public_html/lib/pkp/lib/vendor/illuminate/database/Connectors/ConnectionFactory.php(182): Illuminate\Database\Connectors\MySqlConnector->connect(Array)
#4 [internal function]: Illuminate\Database\Connectors\ConnectionFactory->I in /home/journals/public_html/lib/pkp/lib/vendor/illuminate/database/Connection.php on line 664

[01-Jun-2020 04:16:19 Europe/Istanbul] PHP Fatal error:  Uncaught PDOException: Packets out of order. Expected 0 received 1. Packet size=23 in /home/journals/public_html/lib/pkp/lib/vendor/illuminate/database/Connectors/Connector.php:70
Stack trace:
#0 /home/journals/public_html/lib/pkp/lib/vendor/illuminate/database/Connectors/Connector.php(70): PDO->__construct('mysql:host=loca...', '...', '......', Array)
#1 /home/journals/public_html/lib/pkp/lib/vendor/illuminate/database/Connectors/Connector.php(100): Illuminate\Database\Connectors\Connector->createPdoConnection('mysql:host=loca...', '...', '......', Array)
#2 /home/journals/public_html/lib/pkp/lib/vendor/illuminate/database/Connectors/Connector.php(50): Illuminate\Database\Connectors\Connector->tryAgainIfCausedByLostConnection(Object(PDOException), 'mysql:host=loca...', '...', '......', Array)
#3 /home/journals/public_html/lib/pkp/lib/vendor/illuminate/database/Connectors/MySqlConnector.php(24): Illuminate\Database\Connectors\Connector->createConnection('mysq in /home/journals/public_html/lib/pkp/lib/vendor/illuminate/database/Connectors/Connector.php on line 70

What could be the origin of these errors, do you have any solution for this?
Best regards,
Ugur

Hi @drugurkocak,

You may need to extend your MySQL max_connections configuration parameter.

These are PDO/MySQL error messages, so you might be able to find more guidance by searching outside this forum; the problem is likely to occur in other applications using those tools as well.

Regards,
Alec Smecher
Public Knowledge Project Team