Intern table column names once

synapse/storage/_base.py

@@ -18,7 +18,6 @@ from synapse.api.errors import StoreError
 from synapse.util.logcontext import LoggingContext, PreserveLoggingContext
 from synapse.util.caches.dictionary_cache import DictionaryCache
 from synapse.util.caches.descriptors import Cache
-from synapse.util.caches import intern_dict
 from synapse.storage.engines import PostgresEngine
 import synapse.metrics
 
@@ -356,9 +355,9 @@ class SQLBaseStore(object):
         Returns:
             A list of dicts where the key is the column header.
         """
-        col_headers = list(column[0] for column in cursor.description)
+        col_headers = list(intern(column[0]) for column in cursor.description)
         results = list(
-            intern_dict(dict(zip(col_headers, row))) for row in cursor.fetchall()
+            dict(zip(col_headers, row)) for row in cursor.fetchall()
         )
         return results