diff --git a/synapse/storage/databases/main/events.py b/synapse/storage/databases/main/events.py
index c4188b087d..fa41d33920 100644
--- a/synapse/storage/databases/main/events.py
+++ b/synapse/storage/databases/main/events.py
@@ -1730,12 +1730,11 @@ class PersistEventsStore:
                     keyvalues={"room_id": room_id},
                     values=sliding_sync_table_changes.joined_room_updates,
                     insertion_values={
-                        # The reason we're only *inserting* `event_stream_ordering` here
-                        # is because the column has a `NON NULL` constraint and we need
-                        # *some* answer. If the row already exists, we are trying to
-                        # avoid doing an `UPDATE` and accidentally overwriting the value
-                        # with some stale data since this is just a "best effort" value.
-                        # It's better to just rely on
+                        # The reason we're only *inserting* (not *updating*)
+                        # `event_stream_ordering` here is because the column has a `NON
+                        # NULL` constraint and we need *some* answer. And if the row
+                        # already exists, it already has the correct value and it's
+                        # better to just rely on
                         # `_update_sliding_sync_tables_with_new_persisted_events_txn()`
                         # to do the right thing (same for `bump_stamp`).
                         "event_stream_ordering": sliding_sync_table_changes.joined_room_best_effort_most_recent_stream_ordering
diff --git a/synapse/storage/databases/main/events_bg_updates.py b/synapse/storage/databases/main/events_bg_updates.py
index 8311583125..5e6768d2ce 100644
--- a/synapse/storage/databases/main/events_bg_updates.py
+++ b/synapse/storage/databases/main/events_bg_updates.py
@@ -1691,33 +1691,24 @@ class EventsBackgroundUpdatesStore(StreamWorkerStore, StateDeltasStore, SQLBaseS
                             + "Raising exception so we can just try again."
                         )
 
-                # Pulling keys/values separately is safe and will produce congruent
-                # lists
-                insert_keys = insert_map.keys()
-                insert_values = insert_map.values()
                 # Since we partially update the `sliding_sync_joined_rooms` as new state
                 # is sent, we need to update the state fields `ON CONFLICT`. We just
                 # have to be careful we're not overwriting it with stale data (see
                 # `last_current_state_delta_stream_id` check above).
                 #
-                # We don't need to update `event_stream_ordering` and `bump_stamp` `ON
-                # CONFLICT` because if they are present, that means they are already
-                # up-to-date.
-                sql = f"""
-                    INSERT INTO sliding_sync_joined_rooms
-                        (room_id, event_stream_ordering, bump_stamp, {", ".join(insert_keys)})
-                    VALUES (
-                        ?, ?, ?,
-                        {", ".join("?" for _ in insert_values)}
-                    )
-                    ON CONFLICT (room_id)
-                    DO UPDATE SET
-                        {", ".join(f"{key} = EXCLUDED.{key}" for key in insert_keys)}
-                    """
-                args = [room_id, event_stream_ordering, bump_stamp] + list(
-                    insert_values
+                self.db_pool.simple_upsert_txn(
+                    txn,
+                    table="sliding_sync_joined_rooms",
+                    keyvalues={"room_id": room_id},
+                    values=insert_map,
+                    insertion_values={
+                        # The reason we're only *inserting* (not *updating*) `event_stream_ordering`
+                        # and `bump_stamp` is because if they are present, that means they are already
+                        # up-to-date.
+                        "event_stream_ordering": event_stream_ordering,
+                        "bump_stamp": bump_stamp,
+                    },
                 )
-                txn.execute(sql, args)
 
                 # Keep track of the last successful room_id
                 last_successful_room_id = room_id