Add comments to existing schema deltas that used "CREATE INDEX" directly

1 files changed, 4 insertions, 0 deletions

diff --git a/synapse/storage/schema/delta/31/pushers_index.sql b/synapse/storage/schema/delta/31/pushers_index.sql

index 9027bccc69..a82add88fd 100644
--- a/synapse/storage/schema/delta/31/pushers_index.sql
+++ b/synapse/storage/schema/delta/31/pushers_index.sql
@@ -13,6 +13,10 @@
  * limitations under the License.
  */
 
+/** Using CREATE INDEX directly is deprecated in favour of using background
+ * update see synapse/storage/schema/delta/33/access_tokens_device_index.sql
+ * and synapse/storage/registration.py for an example using
+ * "access_tokens_device_index" **/
  CREATE INDEX event_push_actions_stream_ordering on event_push_actions(
      stream_ordering, user_id
  );