fix: Add reconnect check in case of timeouts on the db side

Signed-off-by: Julius Härtl <jus@bitgrid.net>

lib/private/DB/Connection.php

@@ -41,6 +41,7 @@
 use Doctrine\DBAL\Connections\PrimaryReadReplicaConnection;
 use Doctrine\DBAL\Driver;
 use Doctrine\DBAL\Exception;
+use Doctrine\DBAL\Exception\ConnectionLost;
 use Doctrine\DBAL\Platforms\MySQLPlatform;
 use Doctrine\DBAL\Platforms\OraclePlatform;
 use Doctrine\DBAL\Platforms\SqlitePlatform;
@@ -78,6 +79,7 @@ class Connection extends PrimaryReadReplicaConnection {
 
  /** @var DbDataCollector|null */
  protected $dbDataCollector = null;
+ private int $lastConnectionCheck = 0;
 
  /**
  * Initializes a new instance of the Connection class.
@@ -123,10 +125,13 @@ public function __construct(
  public function connect($connectionName = null) {
  try {
  if ($this->_conn) {
+ $this->reconnectIfNeeded();
  /** @psalm-suppress InternalMethod */
  return parent::connect();
  }
 
+ $this->lastConnectionCheck = time();
+
  // Only trigger the event logger for the initial connect call
  $eventLogger = \OC::$server->get(IEventLogger::class);
  $eventLogger->start('connect:db', 'db connection opened');
@@ -618,4 +623,18 @@ protected function performConnect(?string $connectionName = null): bool {
  }
  return $result;
  }
+
+ private function reconnectIfNeeded(): void {
+ if ($this->lastConnectionCheck + 30 >= time() || $this->isTransactionActive()) {
+ return;
+ }
+
+ try {
+ $this->_conn->query($this->getDriver()->getDatabasePlatform()->getDummySelectSQL());
+ $this->lastConnectionCheck = time();
+ } catch (ConnectionLost|\Exception $e) {
+ $this->logger->warning('Exception during connectivity check, closing and reconnecting', ['exception' => $e]);
+ $this->close();
+ }
+ }
 }