测试

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</div><pre name="code" class="java">Java code ? 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 void heartbeatCheck() { boolean allAlive = false; while (!allAlive) { boolean foundDead = false; DatanodeID nodeID = null; // locate the first dead node. synchronized(heartbeats) { for (Iterator<DatanodeDescriptor> it = heartbeats.iterator();it.hasNext();) { DatanodeDescriptor nodeInfo = it.next(); if (isDatanodeDead(nodeInfo)) { foundDead = true; nodeID = nodeInfo; break; } } } // acquire the fsnamesystem lock, and then remove the dead node. if (foundDead) { synchronized (this) { synchronized(heartbeats) { synchronized (datanodeMap) { DatanodeDescriptor nodeInfo = null; try { nodeInfo = getDatanode(nodeID); } catch (IOException e) { nodeInfo = null; } if (nodeInfo != null && isDatanodeDead(nodeInfo)) { NameNode.stateChangeLog.info("BLOCK* NameSystem.heartbeatCheck: " + "lost heartbeat from " + nodeInfo.getName()); removeDatanode(nodeInfo);//清除与该数据节点相关的数据信息 } } } } } allAlive = !foundDead; } private boolean isDatanodeDead(DatanodeDescriptor node) { return (node.getLastUpdate() < (now() - heartbeatExpireInterval)); }
class HeartbeatMonitor implements Runnable { public void run() { while (fsRunning) { try { heartbeatCheck(); } catch (Exception e) { FSNamesystem.LOG.error(StringUtils.stringifyException(e)); } try { Thread.sleep(heartbeatRecheckInterval); } catch (InterruptedException ie) { } } } }