diff --git a/etiquette/objects.py b/etiquette/objects.py
index 2425dae..7694f4c 100644
--- a/etiquette/objects.py
+++ b/etiquette/objects.py
@@ -112,7 +112,7 @@ class GroupableMixin:
         }
         self.photodb.sql_insert(table=self.group_table, data=data)
 
-        self.photodb._cached_frozen_children = None
+        self.photodb._cached_tag_flat_dict = None
 
     def add_children(self, members):
         for member in members:
@@ -137,7 +137,7 @@ class GroupableMixin:
             If True, all children will be deleted.
             Otherwise they'll just be raised up one level.
         '''
-        self.photodb._cached_frozen_children = None
+        self.photodb._cached_tag_flat_dict = None
         if delete_children:
             for child in self.get_children():
                 child.delete(delete_children=True)
@@ -197,7 +197,7 @@ class GroupableMixin:
             'memberid': member.id,
         }
         self.photodb.sql_delete(table=self.group_table, pairs=pairs)
-        self.photodb._cached_frozen_children = None
+        self.photodb._cached_tag_flat_dict = None
 
     def walk_children(self):
         '''
@@ -1219,7 +1219,7 @@ class Tag(ObjectBase, GroupableMixin):
 
         self.photodb.log.debug('New synonym %s of %s', synname, self.name)
 
-        self.photodb._cached_frozen_children = None
+        self.photodb._cached_tag_flat_dict = None
 
         data = {
             'name': synname,
@@ -1242,7 +1242,7 @@ class Tag(ObjectBase, GroupableMixin):
         '''
         mastertag = self.photodb.get_tag(name=mastertag)
 
-        self.photodb._cached_frozen_children = None
+        self.photodb._cached_tag_flat_dict = None
 
         # Migrate the old tag's synonyms to the new one
         # UPDATE is safe for this operation because there is no chance of duplicates.
@@ -1295,7 +1295,7 @@ class Tag(ObjectBase, GroupableMixin):
     @decorators.transaction
     def delete(self, *, delete_children=False):
         self.photodb.log.debug('Deleting %s', self)
-        self.photodb._cached_frozen_children = None
+        self.photodb._cached_tag_flat_dict = None
         GroupableMixin.delete(self, delete_children=delete_children)
         self.photodb.sql_delete(table='photo_tag_rel', pairs={'tagid': self.id})
         self.photodb.sql_delete(table='tag_synonyms', pairs={'mastername': self.name})
@@ -1354,7 +1354,7 @@ class Tag(ObjectBase, GroupableMixin):
         if syn_exists is None:
             raise exceptions.NoSuchSynonym(synname)
 
-        self.photodb._cached_frozen_children = None
+        self.photodb._cached_tag_flat_dict = None
         self.photodb.sql_delete(table='tag_synonyms', pairs={'name': synname})
 
     @decorators.required_feature('tag.edit')
@@ -1375,7 +1375,7 @@ class Tag(ObjectBase, GroupableMixin):
         else:
             raise exceptions.TagExists(new_name)
 
-        self.photodb._cached_frozen_children = None
+        self.photodb._cached_tag_flat_dict = None
 
         data = {
             'id': self.id,
diff --git a/etiquette/photodb.py b/etiquette/photodb.py
index 81942bb..ab440eb 100644
--- a/etiquette/photodb.py
+++ b/etiquette/photodb.py
@@ -657,7 +657,6 @@ class PDBPhotoMixin:
         (tag_musts, tag_mays, tag_forbids, tag_expression) = tags_fixed
 
         if tag_expression:
-            frozen_children = self.get_cached_frozen_children()
             tag_expression_tree = searchhelpers.tag_expression_tree_builder(
                 tag_expression=tag_expression,
                 photodb=self,
@@ -668,6 +667,7 @@ class PDBPhotoMixin:
                 tag_expression = None
             else:
                 giveback_tag_expression = str(tag_expression_tree)
+                frozen_children = self.get_cached_tag_flat_dict()
                 tag_match_function = searchhelpers.tag_expression_matcher_builder(frozen_children)
         else:
             giveback_tag_expression = None
@@ -1121,7 +1121,7 @@ class PDBTagMixin:
 
         author_id = self.get_user_id_or_none(author)
 
-        self._uncache()
+        self._cached_tag_flat_dict = None
 
         data = {
             'id': tag_id,
@@ -1636,7 +1636,7 @@ class PhotoDB(
         self.log.setLevel(self.config['log_level'])
 
         # OTHER
-        self._cached_frozen_children = None
+        self._cached_tag_flat_dict = None
 
         self.caches = {
             'album': cacheclass.Cache(maxlen=self.config['cache_size']['album']),
@@ -1678,9 +1678,6 @@ class PhotoDB(
         else:
             return f'PhotoDB(data_directory={self.data_directory})'
 
-    def _uncache(self):
-        self._cached_frozen_children = None
-
     def close(self):
         # Wrapped in hasattr because if the object fails __init__, Python will
         # still call __del__ and thus close(), even though the attributes
@@ -1724,10 +1721,11 @@ class PhotoDB(
             self.sql_update(table='id_numbers', pairs=pairs, where_key='tab')
         return new_id
 
-    def get_cached_frozen_children(self):
-        if self._cached_frozen_children is None:
-            self._cached_frozen_children = tag_export.flat_dict(self.get_tags())
-        return self._cached_frozen_children
+    def get_cached_tag_flat_dict(self):
+        if self._cached_tag_flat_dict is None:
+            self._cached_tag_flat_dict = tag_export.flat_dict(self.get_root_tags())
+            print(len(self._cached_tag_flat_dict))
+        return self._cached_tag_flat_dict
 
     def load_config(self):
         (config, needs_rewrite) = configlayers.load_file(