diff --git a/synapse/storage/room.py b/synapse/storage/room.py
index 9e2bf1ab48bfc4cb026fb4e4f536e31183472945..0604f8f27057d9c529b63bdf168efeec8b606ff8 100644
--- a/synapse/storage/room.py
+++ b/synapse/storage/room.py
@@ -310,7 +310,7 @@ class RoomStore(SQLBaseStore):
 
     def _store_event_search_txn(self, txn, event, key, value):
         if isinstance(self.database_engine, PostgresEngine):
-            txn.execute("SET work_mem='256KB'")
+            txn.execute("SET work_mem='256kB'")
             sql = (
                 "INSERT INTO event_search"
                 " (event_id, room_id, key, vector, stream_ordering, origin_server_ts)"
diff --git a/synapse/storage/search.py b/synapse/storage/search.py
index 7b1166f41762c3aacb9c02b08b5aa32f0c2e69b3..f52f3c85922f245015a826c9e7fb07c3f19abe22 100644
--- a/synapse/storage/search.py
+++ b/synapse/storage/search.py
@@ -106,7 +106,7 @@ class SearchStore(BackgroundUpdateStore):
                 event_search_rows.append((event_id, room_id, key, value))
 
             if isinstance(self.database_engine, PostgresEngine):
-                txn.execute("SET work_mem='256KB'")
+                txn.execute("SET work_mem='256kB'")
                 sql = (
                     "INSERT INTO event_search (event_id, room_id, key, vector)"
                     " VALUES (?,?,?,to_tsvector('english', ?))"