Database locking when sending emails

Product Support
1

We have gotten these two error messages in two email sends:

[2015-12-19 15:14:26] mautic.CRITICAL: Uncaught PHP Exception DoctrineDBALDBALException: “An exception occurred while executing ‘UPDATE mautic12_emails SET read_count = ? WHERE id = ?’ with params [23, 311]: SQLSTATE[40001]: Serialization failure: 1213 Deadlock found when trying to get lock; try restarting transaction” at /var/www/html/prod/vendor/doctrine/dbal/lib/Doctrine/DBAL/DBALException.php line 91 {“exception”:"[object] (Doctrine\DBAL\DBALException(code: 0): An exception occurred while executing ‘UPDATE mautic12_emails SET read_count = ? WHERE id = ?’ with params [23, 311]:nnSQLSTATE[40001]: Serialization failure: 1213 Deadlock found when trying to get lock; try restarting transaction at /var/www/html/prod/vendor/doctrine/dbal/lib/Doctrine/DBAL/DBALException.php:91, PDOException(code: 40001): SQLSTATE[40001]: Serialization failure: 1213 Deadlock found when trying to get lock; try restarting transaction at /var/www/html/prod/vendor/doctrine/dbal/lib/Doctrine/DBAL/Connection.php:855)"} []

[2015-12-19 15:20:01] mautic.ERROR: Fatal: Allowed memory size of 536870912 bytes exhausted (tried to allocate 72 bytes) - in file /var/www/html/prod/app/bundles/EmailBundle/EventListener/ReportSubscriber.php - at line 228 [] []



and then:





[2015-12-19 18:47:02] mautic.CRITICAL: Uncaught PHP Exception DoctrineDBALDBALException: “An exception occurred while executing ‘UPDATE mautic12_emails SET read_count = ? WHERE id = ?’ with params [1, 322]: SQLSTATE[40001]: Serialization failure: 1213 Deadlock found when trying to get lock; try restarting transaction” at /var/www/html/prod/vendor/doctrine/dbal/lib/Doctrine/DBAL/DBALException.php line 91 {“exception”:"[object] (Doctrine\DBAL\DBALException(code: 0): An exception occurred while executing ‘UPDATE mautic12_emails SET read_count = ? WHERE id = ?’ with params [1, 322]:nnSQLSTATE[40001]: Serialization failure: 1213 Deadlock found when trying to get lock; try restarting transaction at /var/www/html/prod/vendor/doctrine/dbal/lib/Doctrine/DBAL/DBALException.php:91, PDOException(code: 40001): SQLSTATE[40001]: Serialization failure: 1213 Deadlock found when trying to get lock; try restarting transaction at /var/www/html/prod/vendor/doctrine/dbal/lib/Doctrine/DBAL/Connection.php:855)"} []

2

We have gotten these two error messages in two email sends:
[2015-12-19 15:14:26] mautic.CRITICAL: Uncaught PHP Exception DoctrineDBALDBALException: “An exception occurred while executing ‘UPDATE mautic12_emails SET read_count = ? WHERE id = ?’ with params [23, 311]: SQLSTATE[40001]: Serialization failure: 1213 Deadlock found when trying to get lock; try restarting transaction” at /var/www/html/prod/vendor/doctrine/dbal/lib/Doctrine/DBAL/DBALException.php line 91 {“exception”:"[object] (Doctrine\DBAL\DBALException(code: 0): An exception occurred while executing ‘UPDATE mautic12_emails SET read_count = ? WHERE id = ?’ with params [23, 311]:nnSQLSTATE[40001]: Serialization failure: 1213 Deadlock found when trying to get lock; try restarting transaction at /var/www/html/prod/vendor/doctrine/dbal/lib/Doctrine/DBAL/DBALException.php:91, PDOException(code: 40001): SQLSTATE[40001]: Serialization failure: 1213 Deadlock found when trying to get lock; try restarting transaction at /var/www/html/prod/vendor/doctrine/dbal/lib/Doctrine/DBAL/Connection.php:855)"} []
[2015-12-19 15:20:01] mautic.ERROR: Fatal: Allowed memory size of 536870912 bytes exhausted (tried to allocate 72 bytes) - in file /var/www/html/prod/app/bundles/EmailBundle/EventListener/ReportSubscriber.php - at line 228 [] []

and then:

[2015-12-19 18:47:02] mautic.CRITICAL: Uncaught PHP Exception DoctrineDBALDBALException: “An exception occurred while executing ‘UPDATE mautic12_emails SET read_count = ? WHERE id = ?’ with params [1, 322]: SQLSTATE[40001]: Serialization failure: 1213 Deadlock found when trying to get lock; try restarting transaction” at /var/www/html/prod/vendor/doctrine/dbal/lib/Doctrine/DBAL/DBALException.php line 91 {“exception”:"[object] (Doctrine\DBAL\DBALException(code: 0): An exception occurred while executing ‘UPDATE mautic12_emails SET read_count = ? WHERE id = ?’ with params [1, 322]:nnSQLSTATE[40001]: Serialization failure: 1213 Deadlock found when trying to get lock; try restarting transaction at /var/www/html/prod/vendor/doctrine/dbal/lib/Doctrine/DBAL/DBALException.php:91, PDOException(code: 40001): SQLSTATE[40001]: Serialization failure: 1213 Deadlock found when trying to get lock; try restarting transaction at /var/www/html/prod/vendor/doctrine/dbal/lib/Doctrine/DBAL/Connection.php:855)"} []