Optimize sequence reset on migration

legacy/scripts/migration.py

@@ -64,9 +64,12 @@ def migrate_model(model, to_delete, count_limit=None):
 
     def reset_seq(id):
         # resets id sequence
+        if id > reset_seq.last_id + 1:
             sql_reset_seq = 'ALTER SEQUENCE %s_id_seq RESTART WITH %s;' % (model._meta.db_table, id)
             cursor = connection.cursor()
             cursor.execute(sql_reset_seq)
+        reset_seq.last_id = id
+    reset_seq.last_id = -1
 
     legacy_model = legacy_app.get_model(model.__name__)
     old_pk_name = legacy_model._meta.pk.name