OJS goes very slow sometimes

DiegoG · June 9, 2025, 9:37pm

I’m using OJS 3.4.0-8, and sometimes it goes really slow, I located php error log, and I found this:

Next Illuminate\Database\QueryException: SQLSTATE[HY000] [2002] Connection refused (SQL: SET time_zone = ‘+00:00’) in /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminat$
Stack trace:
#0 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Database/Connection.php(899): Illuminate\Database\Connection->runQueryCallback()
#1 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Database/Connection.php(879): Illuminate\Database\Connection->tryAgainIfCausedByLostConnection()
#2 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Database/Connection.php(723): Illuminate\Database\Connection->handleQueryException()
#3 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Database/Connection.php(546): Illuminate\Database\Connection->run()
#4 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Database/DatabaseManager.php(469): Illuminate\Database\Connection->statement()
#5 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Support/Facades/Facade.php(338): Illuminate\Database\DatabaseManager->__call()
#6 /var/www/html/lib/pkp/classes/core/PKPApplication.php(268): Illuminate\Support\Facades\Facade::__callStatic()
#7 /var/www/html/lib/pkp/classes/core/PKPApplication.php(230): PKP\core\PKPApplication->initializeTimeZone()
#8 /var/www/html/lib/pkp/classes/core/PKPApplication.php(200): PKP\core\PKPApplication->initializeLaravelContainer()
#9 /var/www/html/classes/core/Application.php(50): PKP\core\PKPApplication->__construct()
#10 /var/www/html/lib/pkp/includes/bootstrap.php(37): APP\core\Application->__construct()
#11 /var/www/html/index.php(18): require_once(‘…’)
#12 {main}
thrown in /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Database/Connection.php on line 760
[08-Jun-2025 21:49:59 UTC] PHP Fatal error: Uncaught PDOException: SQLSTATE[HY000] [2002] Connection refused in /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Dat$
Stack trace:
#0 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Database/Connectors/Connector.php(70): PDO->__construct()
#1 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Database/Connectors/Connector.php(100): Illuminate\Database\Connectors\Connector->createPdoConnection()
#2 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Database/Connectors/Connector.php(50): Illuminate\Database\Connectors\Connector->tryAgainIfCausedByLostConnection$
#3 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Database/Connectors/MySqlConnector.php(24): Illuminate\Database\Connectors\Connector->createConnection()
#4 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Database/Connectors/ConnectionFactory.php(184): Illuminate\Database\Connectors\MySqlConnector->connect()
#5 [internal function]: Illuminate\Database\Connectors\ConnectionFactory->Illuminate\Database\Connectors{closure}()
#6 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Database/Connection.php(1181): call_user_func()
#7 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Database/Connection.php(1217): Illuminate\Database\Connection->getPdo()
#8 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Database/Connection.php(486): Illuminate\Database\Connection->getReadPdo()
#9 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Database/Connection.php(414): Illuminate\Database\Connection->getPdoForSelect()
#10 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Database/Connection.php(753): Illuminate\Database\Connection->Illuminate\Database{closure}()
#11 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Database/Connection.php(899): Illuminate\Database\Connection->runQueryCallback()
#12 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Database/Connection.php(879): Illuminate\Database\Connection->tryAgainIfCausedByLostConnection()
#13 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Database/Connection.php(723): Illuminate\Database\Connection->handleQueryException()
#14 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Database/Connection.php(422): Illuminate\Database\Connection->run()
#15 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Database/Query/Builder.php(2706): Illuminate\Database\Connection->select()
#16 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Database/Query/Builder.php(2694): Illuminate\Database\Query\Builder->runSelect()
#17 /var/www/html/lib/pkp/lib/vendor/Laravel/framework/src/Illuminate/Database/Query/Builder.php(3230): Illuminate\Database\Query\Builder->Illuminate\Database\Query{closure}()
#18 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Database/Query/Builder.php(2695): Illuminate\Database\Query\Builder->onceWithColumns()
#19 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Database/Query/Builder.php(3157): Illuminate\Database\Query\Builder->get()
#20 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Database/Query/Builder.php(3085): Illuminate\Database\Query\Builder->aggregate()
#21 /var/www/html/lib/pkp/lib/vendor/laravel/framework/src/Illuminate/Database/Eloquent/Builder.php(1869): Illuminate\Database\Query\Builder->count()
#22 /var/www/html/lib/pkp/classes/queue/JobRunner.php(203): Illuminate\Database\Eloquent\Builder->__call()
#23 /var/www/html/lib/pkp/classes/core/PKPQueueProvider.php(135): PKP\queue\JobRunner->processJobs()
#24 [internal function]: PKP\core\PKPQueueProvider->PKP\core{closure}()
#25 {main}

Any ideas on what could be causing these errors?

Thanks

asmecher · June 14, 2025, 1:06am

Hi @DiegoG,

The error message you quoted simply says that OJS can’t reach the database server. You’ll need to do a little more investigation on the server to see why that is – because it’s undergoing maintenance, or because it’s overloaded, or because of a network problem.

Regards,
Alec Smecher
Public Knowledge Project Team

ZalozbaUL · June 16, 2025, 7:32am

Do you have the “Recommend Similar Articles” plugin enabled? Our OJS website was very slow when this plugin was active.

The “Recommend Articles by Author” plugin works fine, but the Similar Articles plugin performs extensive background searching, which significantly slows down the site.

Maybe this information helps.

asmecher · June 23, 2025, 3:00pm

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