java - 重新连接互联网后，HikariCP 未清理/使用第一个 Oracle 数据库 session

Question

使用桌面 JavaFX 应用程序时，我在 HikariCP 连接到 Oracle 数据库时遇到问题。

堆栈:

Java 8 / JavaFX 8
HikariCP 3.4.2
Oracle Database 11g Release 2
DB driver: ojdbc8 19.3.0.0

当尝试进行数据库查询时 WiFi 互联网连接丢失时，Hikari 指出:

11:09:50.551 DEBUG [HikariPool-1 connection closer] com.zaxxer.hikari.pool.PoolBase: HikariPool-1 - 
    Closing connection oracle.jdbc.driver.T4CConnection@175d7635: (connection is dead)
    11:10:15.513 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.pool.HikariPool: HikariPool-1 - Timeout failure stats (total=0, active=0, idle=0, waiting=0)
    java.sql.SQLTransientConnectionException: HikariPool-1 - Connection is not available, request timed out after 30002ms.
11:10:19.606 DEBUG [HikariPool-1 housekeeper] com.zaxxer.hikari.pool.HikariPool: HikariPool-1 - Pool stats (total=0, active=0, idle=0, waiting=0)
11:10:32.569 DEBUG [HikariPool-1 connection adder] com.zaxxer.hikari.pool.HikariPool: HikariPool-1 - Cannot acquire connection from data source

WiFi 重新连接后，它不再使用相同的连接，Oracle 数据库上的 session 处于 Activity 状态(不是因丢失互联网而关闭)，而是创建新连接:

11:10:48.320 DEBUG [HikariPool-1 connection adder] com.zaxxer.hikari.pool.HikariPool: HikariPool-1 - Added connection oracle.jdbc.driver.T4CConnection@20c1491b
11:10:49.608 DEBUG [HikariPool-1 housekeeper] com.zaxxer.hikari.pool.HikariPool: HikariPool-1 - Pool stats (total=1, active=0, idle=1, waiting=0)

因此 Hikari 创建了新连接，并且在 Oracle 中我看到同一应用程序的 2 个 session 。关闭 JavaFX 应用程序后，第一个 session 不会清除。第二个在退出时被清理。我可以做什么来清洁第一次 session ？这是 Hikari 问题还是 db 问题？

这是 Hikari 配置，主要是默认的:

11:09:17.754 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.HikariConfig: HikariPool-1 - configuration:
11:09:17.759 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.HikariConfig: allowPoolSuspension.............false
11:09:17.759 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.HikariConfig: autoCommit......................true
11:09:17.760 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.HikariConfig: catalog.........................none
11:09:17.760 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.HikariConfig: connectionInitSql...............none
11:09:17.760 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.HikariConfig: connectionTestQuery.............none
11:09:17.760 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.HikariConfig: connectionTimeout...............30000
11:09:17.760 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.HikariConfig: dataSource......................none
11:09:17.761 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.HikariConfig: dataSourceClassName.............none
11:09:17.761 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.HikariConfig: dataSourceJNDI..................none
11:09:17.761 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.HikariConfig: dataSourceProperties............{password=<masked>, prepStmtCacheSqlLimit=2048, cachePrepStmts=true, prepStmtCacheSize=250}
11:09:17.762 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.HikariConfig: driverClassName.................none
11:09:17.762 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.HikariConfig: healthCheckProperties...........{}
11:09:17.762 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.HikariConfig: healthCheckRegistry.............none
11:09:17.762 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.HikariConfig: idleTimeout.....................600000
11:09:17.762 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.HikariConfig: initializationFailTimeout.......1
11:09:17.763 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.HikariConfig: isolateInternalQueries..........false
11:09:17.763 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.HikariConfig: jdbcUrl.........................jdbc:oracle:thin:@xxx
11:09:17.763 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.HikariConfig: leakDetectionThreshold..........20000
11:09:17.763 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.HikariConfig: maxLifetime.....................1800000
11:09:17.763 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.HikariConfig: maximumPoolSize.................1
11:09:17.763 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.HikariConfig: metricRegistry..................none
11:09:17.764 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.HikariConfig: metricsTrackerFactory...........none
11:09:17.764 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.HikariConfig: minimumIdle.....................1
11:09:17.764 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.HikariConfig: password........................<masked>
11:09:17.764 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.HikariConfig: poolName........................"HikariPool-1"
11:09:17.764 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.HikariConfig: readOnly........................false
11:09:17.764 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.HikariConfig: registerMbeans..................false
11:09:17.764 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.HikariConfig: scheduledExecutor...............none
11:09:17.765 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.HikariConfig: schema..........................none
11:09:17.765 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.HikariConfig: threadFactory...................internal
11:09:17.765 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.HikariConfig: transactionIsolation............default
11:09:17.765 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.HikariConfig: username........................"xxx"
11:09:17.765 DEBUG [JavaFX Application Thread] com.zaxxer.hikari.HikariConfig: validationTimeout...............5000

Hikari 中的每个连接都是使用 try-with-resources block 创建的，例如:

 String getValueFromDatabase(String sql) {
        String str = "";
        try (final Connection con = DataSource.getConnection();
             final PreparedStatement stm = createStatement(con, sql);
             final ResultSet rs = stm.executeQuery()) {
            final ResultSetMetaData md = rs.getMetaData();
            while (rs.next()) {
                str = Optional.ofNullable(rs.getString(1)).orElse("");
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return str;
    }

我这样做也是为了检查互联网是否仍然可用(WiFi 可能会丢失)并在连接失败时显示弹出消息(例如 DataSource.getConnection().isClosed()？)。

Answer 1

原始 session 已被孤立。它将在数据库中保持可见，但不会消耗资源，直到它被其配置文件显式终止或超时。本质上它是在等待原来的客户端向它发送另一个网络数据包，这样它就可以通知客户端 session 已终止，然后退出。第二个 session 干净地退出，因为您的应用程序发出了显式注销命令。 DBA 需要配置用户的配置文件以限制空闲时间并清理 session 。请参阅此处:

https://oracle-base.com/articles/misc/clearing-down-old-database-sessions