Allow configuration in queue_consumer.xml to be higher than default

Author: baudeval

app/code/Magento/MessageQueue/Model/Cron/ConsumersRunner.php

@@ -139,8 +139,7 @@ public function run(): void
                     ];
 
                     if ($maxMessages) {
-                        $arguments[] =
-                            '--max-messages=' . min($consumer->getMaxMessages() ?? $maxMessages, $maxMessages);
+                        $arguments = $this->addMaxMessagesArgument($arguments, $consumer, $maxMessages);
                     }
 
                     $command = $php . ' ' . BP . '/bin/magento queue:consumers:start %s %s'
@@ -155,7 +154,7 @@ public function run(): void
                 ];
 
                 if ($maxMessages) {
-                    $arguments[] = '--max-messages=' . min($consumer->getMaxMessages() ?? $maxMessages, $maxMessages);
+                    $arguments = $this->addMaxMessagesArgument($arguments, $consumer, $maxMessages);
                 }
 
                 $command = $php . ' ' . BP . '/bin/magento queue:consumers:start %s %s'
@@ -166,6 +165,32 @@ public function run(): void
         }
     }
 
+    /**
+     * Add max-messages argument and log warning if exceeds default
+     *
+     * @param array $arguments Arguments array to append to
+     * @param ConsumerConfigItemInterface $consumer
+     * @param int $defaultMaxMessages
+     * @return array
+     */
+    private function addMaxMessagesArgument(array $arguments, ConsumerConfigItemInterface $consumer, int $defaultMaxMessages): array
+    {
+        $consumerMaxMessages = $consumer->getMaxMessages() ?? $defaultMaxMessages;
+
+        if ($consumerMaxMessages > $defaultMaxMessages) {
+            $this->logger->warning(__(
+                'Consumer "%1" has max-messages=%2 which exceeds the configured default (%3). This may probably cause high memory usage or long processing times.',
+                $consumer->getName(),
+                $consumerMaxMessages,
+                $defaultMaxMessages
+            ));
+        }
+
+        $arguments[] = '--max-messages=' . $consumerMaxMessages;
+
+        return $arguments;
+    }
+
     /**
      * Checks that the consumer can be run
      *