BUGFIX: Prevent cache overflow when querying nodes by related entities

Without this change new cache entries in Flow_Persistence_Doctrine
are generated for each entry in the relationMap causing massive slowdowns
in Neos f.e. when many assets are deleted as the file system cache
cannot handle large numbers of entries well.

With this change only one entry per number of relations is generated
which is usually only a few and the entries can be reused.

Resolves: #4876

Neos.ContentRepository/Classes/Domain/Repository/NodeDataRepository.php

@@ -1710,24 +1710,29 @@ protected function buildQueryBuilderForRelationMap($relationMap)
         $constraints = [];
         $parameters = [];
 
+        // Use a counter to avoid parameter name conflicts and limit query metadata cache entries to the maximum number of relations
+        $identifierIndex = 0;
+
         foreach ($relationMap as $relatedObjectType => $relatedIdentifiers) {
             foreach ($relatedIdentifiers as $relatedIdentifier) {
                 // entity references like "__identifier": "so-me-uu-id"
-                $constraints[] = '(LOWER(NEOSCR_TOSTRING(n.properties)) LIKE :entity' . md5($relatedIdentifier) . ' )';
-                $parameters['entity' . md5($relatedIdentifier)] = '%"__identifier": "' . strtolower($relatedIdentifier) . '"%';
+                $constraints[] = '(LOWER(NEOSCR_TOSTRING(n.properties)) LIKE :entity' . $identifierIndex . ' )';
+                $parameters['entity' . $identifierIndex] = '%"__identifier": "' . strtolower($relatedIdentifier) . '"%';
 
                 // asset references in text like "asset://so-me-uu-id"
-                $constraints[] = '(LOWER(NEOSCR_TOSTRING(n.properties)) LIKE :asset' . md5($relatedIdentifier) . ' )';
+                $constraints[] = '(LOWER(NEOSCR_TOSTRING(n.properties)) LIKE :asset' . $identifierIndex . ' )';
                 switch ($this->entityManager->getConnection()->getDatabasePlatform()->getName()) {
                     case 'postgresql':
-                        $parameters['asset' . md5($relatedIdentifier)] = '%asset://' . strtolower($relatedIdentifier) . '%';
+                        $parameters['asset' . $identifierIndex] = '%asset://' . strtolower($relatedIdentifier) . '%';
                         break;
                     case 'sqlite':
-                        $parameters['asset' . md5($relatedIdentifier)] = '%asset:\/\/' . strtolower($relatedIdentifier) . '%';
+                        $parameters['asset' . $identifierIndex] = '%asset:\/\/' . strtolower($relatedIdentifier) . '%';
                         break;
                     default:
-                        $parameters['asset' . md5($relatedIdentifier)] = '%asset:\\\\/\\\\/' . strtolower($relatedIdentifier) . '%';
+                        $parameters['asset' . $identifierIndex] = '%asset:\\\\/\\\\/' . strtolower($relatedIdentifier) . '%';
                 }
+
+                $identifierIndex++;
             }
         }