diff --git a/src/test_data.py b/src/test_data.py
index 1ce2cf89..6cba58c2 100644
--- a/src/test_data.py
+++ b/src/test_data.py
@@ -387,4 +387,5 @@ METRICS_WITH_INITIAL_VALUE_ZERO = [
     "waku_store_queries_total",
     "mix_pool_size",
     "libp2p_gossipsub_imreceiving_saved_messages_total",
+    "postgres_payload_size_bytes",
 ]