PS_guc_show_hook.txt

diff --git a/src/backend/replication/logical/logicalxlog.c b/src/backend/replication/logical/logicalxlog.c
index d409eff..7defe97 100644
--- a/src/backend/replication/logical/logicalxlog.c
+++ b/src/backend/replication/logical/logicalxlog.c
@@ -27,6 +27,7 @@
 #include "storage/procarray.h"
 #include "storage/procsignal.h"
 #include "utils/builtins.h"
+#include "utils/guc_hooks.h"
 #include "utils/wait_event.h"
 
 typedef struct XLogLogicalInfoCtlData
@@ -138,6 +139,23 @@ XLogLogicalInfoEnabled(void)
 }
 
 /*
+ * The show_hook for GUC wal_level.
+ */
+const char *show_wal_level(void)
+{
+	switch (wal_level)
+	{
+		case WAL_LEVEL_MINIMAL:
+			return "minimal";
+		case WAL_LEVEL_REPLICA:
+			return IsLogicalDecodingActive() ? "replica-logical" : "replica";
+		case WAL_LEVEL_LOGICAL:
+			return "logical";
+	}
+	return "???";
+}
+
+/*
  * Is logical decoding active?
  */
 bool inline
diff --git a/src/backend/utils/misc/guc_tables.c b/src/backend/utils/misc/guc_tables.c
index c9d8cd7..b7e2b9f 100644
--- a/src/backend/utils/misc/guc_tables.c
+++ b/src/backend/utils/misc/guc_tables.c
@@ -5068,7 +5068,7 @@ struct config_enum ConfigureNamesEnum[] =
 		},
 		&wal_level,
 		WAL_LEVEL_REPLICA, wal_level_options,
-		NULL, NULL, NULL
+		NULL, NULL, show_wal_level
 	},
 
 	{
diff --git a/src/include/utils/guc_hooks.h b/src/include/utils/guc_hooks.h
index 8799921..53fa454 100644
--- a/src/include/utils/guc_hooks.h
+++ b/src/include/utils/guc_hooks.h
@@ -174,5 +174,5 @@ extern void assign_wal_sync_method(int new_wal_sync_method, void *extra);
 extern bool check_synchronized_standby_slots(char **newval, void **extra,
 											 GucSource source);
 extern void assign_synchronized_standby_slots(const char *newval, void *extra);
-
+extern const char *show_wal_level(void);
 #endif							/* GUC_HOOKS_H */