Add "witness register" functionality

dbutils.c

@@ -50,6 +50,7 @@ static void _populate_node_records(PGresult *res, NodeInfoList *node_list);
 static bool _create_update_node_record(PGconn *conn, char *action, t_node_info *node_info);
 static bool _create_event(PGconn *conn, t_configuration_options *options, int node_id, char *event, bool successful, char *details, t_event_info *event_info, bool send_notification);
 
+static bool _is_bdr_db(PGconn *conn, PQExpBufferData *output, bool quiet);
 static void _populate_bdr_node_record(PGresult *res, t_bdr_node_info *node_info, int row);
 static void _populate_bdr_node_records(PGresult *res, BdrNodeInfoList *node_list);
 
@@ -1816,6 +1817,10 @@ parse_node_type(const char *type)
 	{
 		return STANDBY;
 	}
+	else if (strcmp(type, "witness") == 0)
+	{
+		return WITNESS;
+	}
 	else if (strcmp(type, "bdr") == 0)
 	{
 		return BDR;
@@ -1834,6 +1839,8 @@ get_node_type_string(t_server_type type)
 			return "primary";
 		case STANDBY:
 			return "standby";
+		case WITNESS:
+			return "witness";
 		case BDR:
 			return "bdr";
 			/* this should never happen */
@@ -2484,6 +2491,57 @@ update_node_record_conn_priority(PGconn *conn, t_configuration_options *options)
 }
 
 
+/*
+ * Copy node records from primary to witness servers.
+ *
+ * This is used when initially registering a witness server, and
+ * by repmgrd to update the node records when required.
+ */
+
+bool
+witness_copy_node_records(PGconn *primary_conn, PGconn *witness_conn)
+{
+	PGresult   *res = NULL;
+	NodeInfoList nodes = T_NODE_INFO_LIST_INITIALIZER;
+	NodeInfoListCell *cell = NULL;
+
+	begin_transaction(witness_conn);
+
+	/* Defer constraints */
+
+	res = PQexec(witness_conn, "SET CONSTRAINTS ALL DEFERRED");
+	if (!res || PQresultStatus(res) != PGRES_COMMAND_OK)
+	{
+		log_error(_("unable to defer constraints:\n  %s"),
+				  PQerrorMessage(witness_conn));
+		rollback_transaction(witness_conn);
+
+		return false;
+	}
+
+	/* truncate existing records */
+
+	if (truncate_node_records(witness_conn) == false)
+	{
+		rollback_transaction(witness_conn);
+
+		return false;
+	}
+
+	get_all_node_records(primary_conn, &nodes);
+
+	for (cell = nodes.head; cell; cell = cell->next)
+	{
+		create_node_record(witness_conn, NULL, cell->node_info);
+	}
+
+	/* and done */
+	commit_transaction(witness_conn);
+
+	return true;
+}
+
+
 bool
 delete_node_record(PGconn *conn, int node)
 {
@@ -2515,6 +2573,24 @@ delete_node_record(PGconn *conn, int node)
 	return true;
 }
 
+bool
+truncate_node_records(PGconn *conn)
+{
+	PGresult   *res = NULL;
+
+	res = PQexec(conn, "TRUNCATE TABLE repmgr.nodes");
+
+	if (PQresultStatus(res) != PGRES_COMMAND_OK)
+	{
+		log_error(_("unable to truncate node record table:\n  %s"),
+				  PQerrorMessage(conn));
+		PQclear(res);
+		return false;
+	}
+
+	PQclear(res);
+	return true;
+}
 
 void
 get_node_replication_stats(PGconn *conn, t_node_info *node_info)
@@ -3906,8 +3982,8 @@ get_last_wal_receive_location(PGconn *conn)
 /* BDR functions */
 /* ============= */
 
-bool
-is_bdr_db(PGconn *conn, PQExpBufferData *output)
+static bool
+_is_bdr_db(PGconn *conn, PQExpBufferData *output, bool quiet)
 {
 	PQExpBufferData query;
 	PGresult   *res = NULL;
@@ -3938,7 +4014,7 @@ is_bdr_db(PGconn *conn, PQExpBufferData *output)
 
 		if (output != NULL)
 			appendPQExpBuffer(output, "%s", warning);
-		else
+		else if (quiet == false)
 			log_warning("%s", warning);
 
 		return is_bdr_db;
@@ -3959,7 +4035,7 @@ is_bdr_db(PGconn *conn, PQExpBufferData *output)
 
 		if (output != NULL)
 			appendPQExpBuffer(output, "%s", warning);
-		else
+		else if (quiet == false)
 			log_warning("%s", warning);
 	}
 
@@ -3968,6 +4044,19 @@ is_bdr_db(PGconn *conn, PQExpBufferData *output)
 	return is_bdr_db;
 }
 
+bool
+is_bdr_db(PGconn *conn, PQExpBufferData *output)
+{
+	return _is_bdr_db(conn, output, false);
+}
+
+bool
+is_bdr_db_quiet(PGconn *conn)
+{
+	return _is_bdr_db(conn, NULL, true);
+}
+
+
 
 bool
 is_active_bdr_node(PGconn *conn, const char *node_name)