Exception while scanning: An exception occurred while executing 'UPDATE `oc_filecache` SET `size`=? WHERE (`size` <> ? OR `size` IS NULL) AND `fileid` = ? ' with params [500448, 500448, "52568"]:

SQLSTATE[HY000]: General error: 2006 MySQL server has gone away
#0 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/DBALException.php(128): Doctrine\DBAL\Driver\AbstractMySQLDriver->convertException('An exception oc...', Object(Doctrine\DBAL\Driver\PDOException))
#1 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(836): Doctrine\DBAL\DBALException::driverExceptionDuringQuery(Object(Doctrine\DBAL\Driver\PDOMySql\Driver), Object(Doctrine\DBAL\Driver\PDOException), 'UPDATE `oc_file...', Array)
#2 /var/www/nextcloud/lib/private/DB/Connection.php(194): Doctrine\DBAL\Connection->executeQuery('UPDATE `oc_file...', Array, Array, NULL)
#3 /var/www/nextcloud/lib/private/Files/Cache/Cache.php(322): OC\DB\Connection->executeQuery('UPDATE `oc_file...', Array)
#4 /var/www/nextcloud/lib/private/Files/Cache/Scanner.php(399): OC\Files\Cache\Cache->update('52568', Array)
#5 /var/www/nextcloud/lib/private/Files/Cache/Scanner.php(391): OC\Files\Cache\Scanner->scanChildren('files/Documents...', true, 3, '52568', true)
#6 /var/www/nextcloud/lib/private/Files/Cache/Scanner.php(391): OC\Files\Cache\Scanner->scanChildren('files/Documents...', true, 3, '52542', true)
#7 /var/www/nextcloud/lib/private/Files/Cache/Scanner.php(391): OC\Files\Cache\Scanner->scanChildren('files/Documents...', true, 3, '52534', true)
#8 /var/www/nextcloud/lib/private/Files/Cache/Scanner.php(391): OC\Files\Cache\Scanner->scanChildren('files/Documents...', true, 3, '52356', true)
#9 /var/www/nextcloud/lib/private/Files/Cache/Scanner.php(391): OC\Files\Cache\Scanner->scanChildren('files/Documents...', true, 3, '51248', true)
#10 /var/www/nextcloud/lib/private/Files/Cache/Scanner.php(391): OC\Files\Cache\Scanner->scanChildren('files/Documents...', true, 3, '42800', true)
#11 /var/www/nextcloud/lib/private/Files/Cache/Scanner.php(391): OC\Files\Cache\Scanner->scanChildren('files/Documents...', true, 3, '363', true)
#12 /var/www/nextcloud/lib/private/Files/Cache/Scanner.php(391): OC\Files\Cache\Scanner->scanChildren('files/Documents...', true, 3, '355', true)
#13 /var/www/nextcloud/lib/private/Files/Cache/Scanner.php(391): OC\Files\Cache\Scanner->scanChildren('files/Documents', true, 3, '353', true)
#14 /var/www/nextcloud/lib/private/Files/Cache/Scanner.php(391): OC\Files\Cache\Scanner->scanChildren('files', true, 3, '2', true)
#15 /var/www/nextcloud/lib/private/Files/Cache/Scanner.php(322): OC\Files\Cache\Scanner->scanChildren('', true, 3, '1', true)
#16 /var/www/nextcloud/lib/private/Files/Utils/Scanner.php(196): OC\Files\Cache\Scanner->scan('', true, 3)
#17 /var/www/nextcloud/apps/files/lib/Command/Scan.php(159): OC\Files\Utils\Scanner->scan('/william')
#18 /var/www/nextcloud/apps/files/lib/Command/Scan.php(227): OCA\Files\Command\Scan->scanFiles('william', '/william', false, Object(Symfony\Component\Console\Output\ConsoleOutput), false)
#19 /var/www/nextcloud/3rdparty/symfony/console/Command/Command.php(256): OCA\Files\Command\Scan->execute(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#20 /var/www/nextcloud/core/Command/Base.php(161): Symfony\Component\Console\Command\Command->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#21 /var/www/nextcloud/3rdparty/symfony/console/Application.php(818): OC\Core\Command\Base->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#22 /var/www/nextcloud/3rdparty/symfony/console/Application.php(186): Symfony\Component\Console\Application->doRunCommand(Object(OCA\Files\Command\Scan), Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#23 /var/www/nextcloud/3rdparty/symfony/console/Application.php(117): Symfony\Component\Console\Application->doRun(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#24 /var/www/nextcloud/lib/private/Console/Application.php(169): Symfony\Component\Console\Application->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#25 /var/www/nextcloud/console.php(90): OC\Console\Application->run()
#26 /var/www/nextcloud/occ(11): require_once('/var/www/nextcl...')
#27 {main}

+---------+-------+--------------+
| Folders | Files | Elapsed time |
+---------+-------+--------------+
| 26863   | 49098 | 00:16:05     |
+---------+-------+--------------+
PHP Fatal error:  Uncaught PDOException: SQLSTATE[HY000]: General error: 2006 MySQL server has gone away in /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Driver/PDOStatement.php:91
Stack trace:
#0 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Driver/PDOStatement.php(91): PDOStatement->execute(Array)
#1 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(989): Doctrine\DBAL\Driver\PDOStatement->execute(Array)
#2 /var/www/nextcloud/lib/private/DB/Connection.php(215): Doctrine\DBAL\Connection->executeUpdate('UPDATE `oc_file...', Array, Array)
#3 /var/www/nextcloud/lib/private/Lock/DBLockingProvider.php(203): OC\DB\Connection->executeUpdate('UPDATE `oc_file...', Array)
#4 /var/www/nextcloud/lib/private/Lock/AbstractLockingProvider.php(120): OC\Lock\DBLockingProvider->releaseLock('files/684c6c188...', 2)
#5 /var/www/nextcloud/lib/private/Lock/DBLockingProvider.php(260): OC\Lock\AbstractLockingProvider->releaseAll()
#6 [internal function]: OC\Lock\DBLockingProvider->releaseAll()
#7  in /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Driver/AbstractMySQLDriver.php on line 116