1 /* 2 Copyright (c) 2010, 2011, Oracle and/or its affiliates. All rights reserved. 3 4 This program is free software; you can redistribute it and/or modify 5 it under the terms of the GNU General Public License, version 2.0, 6 as published by the Free Software Foundation. 7 8 This program is also distributed with certain software (including 9 but not limited to OpenSSL) that is licensed under separate terms, 10 as designated in a particular file or component or in included license 11 documentation. The authors of MySQL hereby grant you an additional 12 permission to link the program and your derivative works with the 13 separately licensed software that they have included with MySQL. 14 15 This program is distributed in the hope that it will be useful, 16 but WITHOUT ANY WARRANTY; without even the implied warranty of 17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 18 GNU General Public License, version 2.0, for more details. 19 20 You should have received a copy of the GNU General Public License 21 along with this program; if not, write to the Free Software 22 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 23 */ 24 25 #ifndef NODEPING_HPP 26 #define NODEPING_HPP 27 28 #include "SignalData.hpp" 29 30 31 /* 32 * NodePingReq/Conf is sent between QMGR nodes to help determine the 33 * available connectivity in a cluster experiencing heartbeat problems 34 * 35 * When a node detects that it has not received a heartbeat from a 36 * connected node for the heartbeat period, it initiates a global 37 * connectivity check protocol by sending a NODE_PING_REQ signal to all 38 * nodes considered to be running. 39 * 40 * On receiving this signal, a node will respond with NODE_PING_CONF to 41 * the sender, and begin its own connectivity check, if it is not 42 * already involved in one. 43 * 44 * In this way, all nodes reachable within some latency n will begin 45 * a connectivity check. If they do not receive a NODE_PING_CONF from a 46 * peer node within some further latency m, then they consider it to 47 * be suspect, and after a further latency p they consider it failed. 48 * 49 * In environments where latency between nodes fluctuates, but 50 * connectivity is maintained (for example where TCP connections observe 51 * latency due to underlying IP re-routing/failover), the connectivity 52 * check allows nodes to arm themselves in preparation for the potential 53 * race of FAIL_REP signals that can arise in these situations, by marking 54 * connections experiencing latency as SUSPECT. Once a node is marked as 55 * SUSPECT, FAIL_REP signals originating from it may not be trusted or 56 * acted upon. 57 */ 58 59 class NodePingReq { 60 /** 61 * Sender(s) / Receiver(s) 62 */ 63 friend class Qmgr; 64 public: 65 STATIC_CONST( SignalLength = 2 ); 66 67 Uint32 senderData; 68 Uint32 senderRef; 69 }; 70 71 class NodePingConf { 72 /** 73 * Sender(s) / Receiver(s) 74 */ 75 friend class Qmgr; 76 public: 77 STATIC_CONST( SignalLength = 2 ); 78 79 Uint32 senderData; 80 Uint32 senderRef; 81 }; 82 83 #endif 84