diff --git a/Processor/Processor.php b/Processor/Processor.php
index 55779ff..0413da1 100644
--- a/Processor/Processor.php
+++ b/Processor/Processor.php
@@ -33,7 +33,7 @@ public function setContainer(ContainerInterface $container = null)
     public function processQuery($queryString, $variables = [])
     {
         if ($this->logger) {
-            $this->logger->debug(sprintf('GraphQL query: %s', $queryString), $variables);
+            $this->logger->debug(sprintf('GraphQL query: %s', $queryString), (array) $variables);
         }
 
         parent::processQuery($queryString, $variables);