diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 07eac07b9ce..493ce92674e 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -1143,2 +1143,3 @@ XLogWalRcvSendReply(bool force, bool requestReply, bool checkApply)

+pg_usleep(10000);
      /* Get current timestamp. */
diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c
index 04aa770d981..19cda3a6b51 100644
--- a/src/backend/replication/walsender.c
+++ b/src/backend/replication/walsender.c
@@ -2521,2 +2521,3 @@ ProcessStandbyReplyMessage(void)

+pg_usleep(100000);
      /* the caller already consumed the msgtype byte */