Before a user is getting scanned the database connection is re-established

apps/files/lib/Command/Scan.php

@@ -28,9 +28,11 @@
 
 namespace OCA\Files\Command;
 
+use Doctrine\DBAL\Connection;
 use OC\Core\Command\Base;
 use OC\ForbiddenException;
 use OCP\Files\StorageNotAvailableException;
+use OCP\IDBConnection;
 use OCP\IUserManager;
 use Symfony\Component\Console\Input\InputArgument;
 use Symfony\Component\Console\Input\InputInterface;
@@ -106,7 +108,8 @@ class Scan extends Base {
 	}
 
 	protected function scanFiles($user, $path, $verbose, OutputInterface $output, $backgroundScan = false) {
-		$scanner = new \OC\Files\Utils\Scanner($user, \OC::$server->getDatabaseConnection(), \OC::$server->getLogger());
+		$connection = $this->reconnectToDatabase($output);
+		$scanner = new \OC\Files\Utils\Scanner($user, $connection, \OC::$server->getLogger());
 		# check on each file/folder if there was a user interrupt (ctrl-c) and throw an exception
 		# printout and count
 		if ($verbose) {
@@ -318,4 +321,26 @@ class Scan extends Base {
 		return date('H:i:s', $secs);
 	}
 
+	/**
+	 * @return \OCP\IDBConnection
+	 */
+	protected function reconnectToDatabase(OutputInterface $output) {
+		/** @var Connection | IDBConnection $connection*/
+		$connection = \OC::$server->getDatabaseConnection();
+		try {
+			$connection->close();
+		} catch (\Exception $ex) {
+			$output->writeln("<info>Error while disconnecting from database: {$ex->getMessage()}</info>");
+		}
+		while (!$connection->isConnected()) {
+			try {
+				$connection->connect();
+			} catch (\Exception $ex) {
+				$output->writeln("<info>Error while re-connecting to database: {$ex->getMessage()}</info>");
+				sleep(60);
+			}
+		}
+		return $connection;
+	}
+
 }