Change return type of is_downstream_node_attached() from bool to NodeAttached

This enables us to better determine whether a node is definitively
attached, definitively not attached, or if it was not possible to
determine the attached state.

dbutils.c

@@ -5287,7 +5287,7 @@ get_node_replication_stats(PGconn *conn, t_node_info *node_info)
 }
 
 
-bool
+NodeAttached
 is_downstream_node_attached(PGconn *conn, char *node_name)
 {
 	PQExpBufferData query;
@@ -5297,7 +5297,8 @@ is_downstream_node_attached(PGconn *conn, char *node_name)
 	initPQExpBuffer(&query);
 
 	appendPQExpBuffer(&query,
-					  " SELECT pg_catalog.count(*) FROM pg_catalog.pg_stat_replication "
+					  " SELECT pg_catalog.count(*) "
+					  "   FROM pg_catalog.pg_stat_replication "
 					  "  WHERE application_name = '%s'",
 					  node_name);
 
@@ -5312,7 +5313,7 @@ is_downstream_node_attached(PGconn *conn, char *node_name)
 		termPQExpBuffer(&query);
 		PQclear(res);
 
-		return false;
+		return NODE_ATTACHED_UNKNOWN;
 	}
 
 	if (PQntuples(res) != 1)
@@ -5322,7 +5323,7 @@ is_downstream_node_attached(PGconn *conn, char *node_name)
 		termPQExpBuffer(&query);
 		PQclear(res);
 
-		return false;
+		return NODE_ATTACHED_UNKNOWN;
 	}
 
 	c = atoi(PQgetvalue(res, 0, 0));
@@ -5334,14 +5335,14 @@ is_downstream_node_attached(PGconn *conn, char *node_name)
 	{
 		log_verbose(LOG_WARNING, _("node \"%s\" not found in \"pg_stat_replication\""), node_name);
 
-		return false;
+		return NODE_DETACHED;
 	}
 
 	if (c > 1)
 		log_verbose(LOG_WARNING, _("multiple entries with \"application_name\" set to  \"%s\" found in \"pg_stat_replication\""),
 					node_name);
 
-	return true;
+	return NODE_ATTACHED;
 }
 
 

dbutils.h

@@ -118,6 +118,7 @@ typedef enum
 } BackupState;
 
 
+
 /*
  * Struct to store extension version information
  */
@@ -574,7 +575,7 @@ void		init_replication_info(ReplInfo *replication_info);
 bool		get_replication_info(PGconn *conn, t_server_type node_type, ReplInfo *replication_info);
 int			get_replication_lag_seconds(PGconn *conn);
 void		get_node_replication_stats(PGconn *conn, t_node_info *node_info);
-bool		is_downstream_node_attached(PGconn *conn, char *node_name);
+NodeAttached is_downstream_node_attached(PGconn *conn, char *node_name);
 void		set_upstream_last_seen(PGconn *conn, int upstream_node_id);
 int			get_upstream_last_seen(PGconn *conn, t_server_type node_type);
 

repmgr-action-node.c

@@ -294,7 +294,7 @@ do_node_status(void)
 				continue;
 			}
 
-			if (is_downstream_node_attached(conn, node_cell->node_info->node_name) == false)
+			if (is_downstream_node_attached(conn, node_cell->node_info->node_name) != NODE_ATTACHED)
 			{
 				missing_nodes_count++;
 				item_list_append_format(&missing_nodes,
@@ -1166,7 +1166,7 @@ do_node_check_downstream(PGconn *conn, OutputMode mode, CheckStatusList *list_ou
 			continue;
 		}
 
-		if (is_downstream_node_attached(conn, cell->node_info->node_name) == false)
+		if (is_downstream_node_attached(conn, cell->node_info->node_name) != NODE_ATTACHED)
 		{
 			missing_nodes_count++;
 			item_list_append_format(&missing_nodes,
@@ -2562,9 +2562,10 @@ do_node_rejoin(void)
 
 		for (;  i < config_file_options.node_rejoin_timeout; i++)
 		{
-			success = is_downstream_node_attached(primary_conn, config_file_options.node_name);
+			NodeStatus node_attached = is_downstream_node_attached(primary_conn,
+																   config_file_options.node_name);
 
-			if (success == true)
+			if (node_attached == NODE_ATTACHED)
 			{
 				log_verbose(LOG_INFO, _("node %i has attached to its upstream node"),
 							config_file_options.node_id);
@@ -2612,7 +2613,9 @@ do_node_rejoin(void)
 	else
 	{
 		/* -W/--no-wait provided - check once */
-		success = is_downstream_node_attached(primary_conn, config_file_options.node_name);
+		NodeStatus node_attached = is_downstream_node_attached(primary_conn, config_file_options.node_name);
+		if (node_attached == NODE_ATTACHED)
+			success = true;
 	}
 
 	/*

repmgr-action-standby.c

@@ -1620,7 +1620,7 @@ do_standby_register(void)
 			else
 			{
 				/* check our standby is connected */
-				if (is_downstream_node_attached(upstream_conn, config_file_options.node_name) == true)
+				if (is_downstream_node_attached(upstream_conn, config_file_options.node_name) == NODE_ATTACHED)
 				{
 					log_verbose(LOG_INFO, _("local node is attached to specified upstream node %i"), runtime_options.upstream_node_id);
 				}
@@ -1679,7 +1679,7 @@ do_standby_register(void)
 						primary_node_id);
 
 			/* check our standby is connected */
-			if (is_downstream_node_attached(primary_conn, config_file_options.node_name) == true)
+			if (is_downstream_node_attached(primary_conn, config_file_options.node_name) == NODE_ATTACHED)
 			{
 				log_verbose(LOG_INFO, _("local node is attached to primary"));
 			}
@@ -2858,9 +2858,13 @@ do_standby_follow(void)
 
 	for (timer = 0; timer < config_file_options.standby_follow_timeout; timer++)
 	{
-		success = is_downstream_node_attached(follow_target_conn, config_file_options.node_name);
+		NodeAttached node_attached = is_downstream_node_attached(follow_target_conn, config_file_options.node_name);
-		if (success == true)
+
+		if (node_attached == NODE_ATTACHED)
+		{
+			success = true;
 			break;
+		}
 
 		log_verbose(LOG_DEBUG, "sleeping %i of max %i seconds waiting for standby to attach to primary",
 					timer + 1,
@@ -3411,7 +3415,7 @@ do_standby_switchover(void)
 		exit(ERR_BAD_CONFIG);
 	}
 
-	if (is_downstream_node_attached(remote_conn, local_node_record.node_name) == false)
+	if (is_downstream_node_attached(remote_conn, local_node_record.node_name) != NODE_ATTACHED)
 	{
 		log_error(_("local node \"%s\" (ID: %i) is not attached to demotion candidate \"%s\" (ID: %i)"),
 				  local_node_record.node_name,