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Hikari 连接池关闭连接

作者:互联网

项目中使用hakari 连接池管理conn,在使用过程中遇到如果没有声明事物,连接不会关闭的情况,故花时间看了hakari的源码

首先,hikari有一堆配置,这个配置的注意事项可以去网上找一下,这里提供一个地址 https://blog.51cto.com/1197822/2298344

另外如果要看具体问题与解决方法最好去github 上找一下。

 

HikariConfig 另外配置类中也做了详细说明,推荐看下这个类,其中作者标名了某些配置的默认值、执行过程中可改变与不可改变的值

   private static final char[] ID_CHARACTERS = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ".toCharArray();
   private static final long CONNECTION_TIMEOUT = SECONDS.toMillis(30);
   private static final long VALIDATION_TIMEOUT = SECONDS.toMillis(5);
   private static final long IDLE_TIMEOUT = MINUTES.toMillis(10);
   private static final long MAX_LIFETIME = MINUTES.toMillis(30);
   private static final int DEFAULT_POOL_SIZE = 10;

   private static boolean unitTest = false;

   // Properties changeable at runtime through the HikariConfigMXBean
   //
   private volatile long connectionTimeout;
   private volatile long validationTimeout;
   private volatile long idleTimeout;
   private volatile long leakDetectionThreshold;
   private volatile long maxLifetime;
   private volatile int maxPoolSize;
   private volatile int minIdle;
   private volatile String username;
   private volatile String password;

   // Properties NOT changeable at runtime
   //
   private long initializationFailTimeout;
   private String catalog;
   private String connectionInitSql;
   private String connectionTestQuery;
   private String dataSourceClassName;
   private String dataSourceJndiName;
   private String driverClassName;
   private String jdbcUrl;
   private String poolName;
   private String schema;
   private String transactionIsolationName;
   private boolean isAutoCommit;
   private boolean isReadOnly;
   private boolean isIsolateInternalQueries;
   private boolean isRegisterMbeans;
   private boolean isAllowPoolSuspension;
   private DataSource dataSource;
   private Properties dataSourceProperties;
   private ThreadFactory threadFactory;
   private ScheduledExecutorService scheduledExecutor;
   private MetricsTrackerFactory metricsTrackerFactory;
   private Object metricRegistry;
   private Object healthCheckRegistry;
   private Properties healthCheckProperties;

 

关于hikari 如何处理空闲连接的:

hikaripool类中有一个内部类,huosekeeper,它干的活就是维持空闲连接与消除过于的连接。下面是源码

它的工作机制就是,在程序启动后,datasource 交给 hikari 池代理,初始化空闲连接后(根据你的最小空闲连接配置决定),启动一个schedule,周期默认是30S

在调度任务执行的过程中会检查连接池包(currentBag)中连接的状态,如果是 NOT_IN_USER 的连接,那么将会进行释放。

如果当前空闲连接小于预定义的连接数,hikari会create 空闲连接,直接满足最小空闲连接要求(默认最小是10)

   private final class HouseKeeper implements Runnable
   {
      private volatile long previous = plusMillis(currentTime(), -HOUSEKEEPING_PERIOD_MS);

      @Override
      public void run()
      {
         try {
            // refresh timeouts in case they changed via MBean
            connectionTimeout = config.getConnectionTimeout();
            validationTimeout = config.getValidationTimeout();
            leakTaskFactory.updateLeakDetectionThreshold(config.getLeakDetectionThreshold());

            final long idleTimeout = config.getIdleTimeout();
            final long now = currentTime();

            // Detect retrograde time, allowing +128ms as per NTP spec.
            if (plusMillis(now, 128) < plusMillis(previous, HOUSEKEEPING_PERIOD_MS)) {
               LOGGER.warn("{} - Retrograde clock change detected (housekeeper delta={}), soft-evicting connections from pool.",
                           poolName, elapsedDisplayString(previous, now));
               previous = now;
               softEvictConnections();
               return;
            }
            else if (now > plusMillis(previous, (3 * HOUSEKEEPING_PERIOD_MS) / 2)) {
               // No point evicting for forward clock motion, this merely accelerates connection retirement anyway
               LOGGER.warn("{} - Thread starvation or clock leap detected (housekeeper delta={}).", poolName, elapsedDisplayString(previous, now));
            }

            previous = now;

            String afterPrefix = "Pool ";
            if (idleTimeout > 0L && config.getMinimumIdle() < config.getMaximumPoolSize()) {
               logPoolState("Before cleanup ");
               afterPrefix = "After cleanup  ";

               final List<PoolEntry> notInUse = connectionBag.values(STATE_NOT_IN_USE);
               int toRemove = notInUse.size() - config.getMinimumIdle();
               for (PoolEntry entry : notInUse) {
                  if (toRemove > 0 && elapsedMillis(entry.lastAccessed, now) > idleTimeout && connectionBag.reserve(entry)) {
                     closeConnection(entry, "(connection has passed idleTimeout)");
                     toRemove--;
                  }
               }
            }

            logPoolState(afterPrefix);

            fillPool(); // Try to maintain minimum connections
         }
         catch (Exception e) {
            LOGGER.error("Unexpected exception in housekeeping task", e);
         }
      }
   }

那么重点就在于NOT_IN_USE 状态什么时候设置的,只有一个地方会直接把IN_USER 设置为NOT_IN_USER

 

 

 

在currentBag 中,那么什么时候会调用requite 方法,当conn 关闭的时候,通过hikari 代理最终close 会执行到requite 方法,这时候hikari 会把当前连接池中的连接,

也就是下图中的bagEntry 设置为NOT_IN_USE, 设置完毕后,具体清理工作交给housekeeper 处理。

另外当我们使用conn 的时候,hikari 同样会获取连接池中的当前空闲连接交给你使用。

 

 

 

而我遇到的问题是,当调用一个自定义的service 方法,并且其中有操作数据库的操作(个人调用的是一个oracle 存储过程),由于spring jpa 事物管理中对于自定义的数据库操作并没有加上

我定义的方法相关配置,于是在调用存储过程后没有调用close 方法,故hikari 不会设置激活状态下的连接为空闲状态,随着时间的推移,最终导致连接池中的数量达到了maxpoolsize,无法再次获取连接导致connecttimeout异常。

 

最后一点是:遇到hikari 的问题,最好把hikari的log日志打开(设置debug),这样默认情况下每30S ,hikari 的housekeeper 会打印当前池中的连接情况,包括连接总数,激活数,空闲数与等待数量。

<Logger name="com.zaxxer.hikari" level="debug"></Logger>

 

另外这个问题解决方法就是让conn 每次使用完后管理连接,从而通知hikari 代理把当前使用的连接设置为空闲连接进行回收。

在方法上加上声明式事物注解,即可解决。

   @Override
    @Transactional(rollbackFor = Exception.class)
    public void callLogStatistic(String inBeginTime, String inSiteId) {
        repository.logStatistic(inBeginTime, inSiteId);
    }

 

标签:volatile,String,private,Hikari,long,关闭,hikari,连接,连接池
来源: https://www.cnblogs.com/jony-it/p/12859473.html