diff --git a/doc/src/sgml/protocol.sgml b/doc/src/sgml/protocol.sgml
index c923d3b154c..6be5a149aec 100644
--- a/doc/src/sgml/protocol.sgml
+++ b/doc/src/sgml/protocol.sgml
@@ -1471,9 +1471,9 @@ The commands accepted in walsender mode are:
- The receiving process can send a status update back to the sender at
- any time, using the following message format (also in the payload of
- a CopyData message):
+ The receiving process can send replies back to the sender at any time,
+ using one of the following message formats (also in the payload of a
+ CopyData message):
@@ -1545,6 +1545,63 @@ The commands accepted in walsender mode are:
+
+
+
+
+
+ Hot Standby feedback message (F)
+
+
+
+
+
+
+ Byte1('h')
+
+
+
+ Identifies the message as a Hot Standby feedback message.
+
+
+
+
+
+ Byte8
+
+
+
+ The server's system clock at the time of transmission,
+ given in TimestampTz format.
+
+
+
+
+
+ Byte4
+
+
+
+ The standby's current xmin.
+
+
+
+
+
+ Byte4
+
+
+
+ The standby's current epoch.
+
+
+
+
+
+
+
+
+