druid 数据源 removeAbandoned 源码分析

最新推荐文章于 2023-12-01 21:37:42 发布

原创最新推荐文章于 2023-12-01 21:37:42 发布 · 261 阅读

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本文介绍了一个连接池中废弃连接的检测与回收机制实现。通过定时任务定期检查活动连接，若连接空闲时间超过设定阈值，则将其标记为废弃并进行回收。此外，还记录了连接废弃时的相关信息，包括连接创建时间、线程状态等。

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  protected void createAndStartDestroyThread() {
        destroyTask = new DestroyTask();

        if (destroyScheduler != null) {
            // <!-- 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒 -->

       //   <property name="timeBetweenEvictionRunsMillis" value="60000" />


            long period = timeBetweenEvictionRunsMillis;
            if (period <= 0) {
                period = 1000;
            }
            destroySchedulerFuture = destroyScheduler.scheduleAtFixedRate(destroyTask, period, period,
                                                                          TimeUnit.MILLISECONDS);
            initedLatch.countDown();
            return;
        }

        String threadName = "Druid-ConnectionPool-Destroy-" + System.identityHashCode(this);
        destroyConnectionThread = new DestroyConnectionThread(threadName);
        destroyConnectionThread.start();
    }

public class DestroyTask implements Runnable {

        @Override
        public void run() {
            shrink(true);

            if (isRemoveAbandoned()) {
                removeAbandoned();
            }
        }

    }

 public int removeAbandoned() {
        int removeCount = 0;
        
        System.out.println("我来了.........................................."+DateUtils.getCurrentFullDateStr());

        long currrentNanos = System.nanoTime();

        List<DruidPooledConnection> abandonedList = new ArrayList<DruidPooledConnection>();

        synchronized (activeConnections) {
            Iterator<DruidPooledConnection> iter = activeConnections.keySet().iterator();

            for (; iter.hasNext();) {
                DruidPooledConnection pooledConnection = iter.next();

                if (pooledConnection.isRunning()) {
                    continue;
                }

                long timeMillis = (currrentNanos - pooledConnection.getConnectedTimeNano()) / (1000 * 1000);

                if (timeMillis >= removeAbandonedTimeoutMillis) {
                    iter.remove();
                    pooledConnection.setTraceEnable(false);
                    abandonedList.add(pooledConnection);
                }
            }
        }

        if (abandonedList.size() > 0) {
            for (DruidPooledConnection pooledConnection : abandonedList) {
                synchronized (pooledConnection) {
                    if (pooledConnection.isDisable()) {
                        continue;
                    }
                }
                
                System.out.println("abandonedList>>>>>>>>>>>>>>>>>>>>>>"+DateUtils.getCurrentFullDateStr());
                
                JdbcUtils.close(pooledConnection);
                pooledConnection.abandond();
                removeAbandonedCount++;
                removeCount++;

                if (isLogAbandoned()) {
                    StringBuilder buf = new StringBuilder();
                    buf.append("abandon connection, owner thread: ");
                    buf.append(pooledConnection.getOwnerThread().getName());
                    buf.append(", connected at : ");
                    buf.append(pooledConnection.getConnectedTimeMillis());
                    buf.append(", open stackTrace\n");

                    StackTraceElement[] trace = pooledConnection.getConnectStackTrace();
                    for (int i = 0; i < trace.length; i++) {
                        buf.append("\tat ");
                        buf.append(trace[i].toString());
                        buf.append("\n");
                    }

                    buf.append("ownerThread current state is "+pooledConnection.getOwnerThread().getState() + ", current stackTrace\n");
                    trace = pooledConnection.getOwnerThread().getStackTrace();
                    for (int i = 0; i < trace.length; i++) {
                        buf.append("\tat ");
                        buf.append(trace[i].toString());
                        buf.append("\n");
                    }

                    LOG.error(buf.toString());
                }
            }
        }

        return removeCount;
    }