diff --git a/models/DataObject/ClassDefinition.php b/models/DataObject/ClassDefinition.php
index 118310bbe0c..b17887c7cd8 100644
--- a/models/DataObject/ClassDefinition.php
+++ b/models/DataObject/ClassDefinition.php
@@ -407,6 +407,8 @@ public static function cleanupForExport(&$data)
      */
     private function exists()
     {
+        // cache for class definitions needs to be cleared here to avoid wrong exists but still using the cache
+        Cache::clearTags(['ClassDefinitionDao']);
         $name = $this->getDao()->getNameById($this->getId());
 
         return is_string($name);
diff --git a/models/DataObject/ClassDefinition/Dao.php b/models/DataObject/ClassDefinition/Dao.php
index 6402ff76c06..350818cf678 100644
--- a/models/DataObject/ClassDefinition/Dao.php
+++ b/models/DataObject/ClassDefinition/Dao.php
@@ -15,6 +15,8 @@
 
 namespace Pimcore\Model\DataObject\ClassDefinition;
 
+use Pimcore\Cache;
+use Pimcore\Db\Helper;
 use Pimcore\Logger;
 use Pimcore\Model;
 use Pimcore\Model\DataObject;
@@ -39,6 +41,26 @@ class Dao extends Model\Dao\AbstractDao
      */
     protected $tableDefinitions = null;
 
+    /**
+     * Helper to minimize db queries used when looking up classes id / name.
+     *
+     * Mapping is actively updated as soon as a class is saved.
+     *
+     * @param bool $skipCache
+     * @return array
+     * @see self::save()
+     *
+     */
+    protected function getClassNameIdMap(bool $skipCache = false): array
+    {
+        static $mapping;
+        if ($skipCache || (!isset($mapping) && !is_array(($mapping = Cache::load(md5(__METHOD__)))))) {
+            $mapping = Helper::fetchPairs($this->db, 'SELECT id, name FROM classes');
+            Cache::save($mapping, md5(__METHOD__), ['ClassDefinitionDao'], null, 0, true);
+        }
+        return $mapping;
+    }
+
     /**
      * @param string $id
      *
@@ -48,9 +70,8 @@ public function getNameById($id)
     {
         try {
             if (!empty($id)) {
-                if ($name = $this->db->fetchOne('SELECT name FROM classes WHERE id = ?', [$id])) {
-                    return $name;
-                }
+                $mapping = $this->getClassNameIdMap();
+                return $mapping[$id] ?? null;
             }
         } catch (\Exception $e) {
         }
@@ -71,7 +92,11 @@ public function getIdByName($name)
 
         try {
             if (!empty($name)) {
-                $id = $this->db->fetchOne('SELECT id FROM classes WHERE name = ?', [$name]);
+                $mapping = $this->getClassNameIdMap();
+                if (($v = array_search($name, $mapping, true)) !== false) {
+                    $id = $v;
+                }
+
             }
         } catch (\Exception $e) {
         }
@@ -97,6 +122,8 @@ public function save($isUpdate = true)
         }
 
         $this->update();
+        // Update class name / id mapping in cache.
+        $this->getClassNameIdMap(true);
     }
 
     /**
@@ -300,6 +327,8 @@ public function delete()
 
         // clean slug table
         DataObject\Data\UrlSlug::handleClassDeleted($this->model->getId());
+        // Update class name / id mapping in cache.
+        $this->getClassNameIdMap(true);
     }
 
     /**