常用数据库连接池 (DBCP、c3p0、Druid) 配置说明 (6)

NOTE - Make sure your connection has some resources left for the other statements. Pooling PreparedStatements may keep their cursors open in the database, causing a connection to run out of cursors, especially if maxOpenPreparedStatements is left at the default (unlimited) and an application opens a large number of different PreparedStatements per connection. To avoid this problem, maxOpenPreparedStatements should be set to a value less than the maximum number of cursors that can be open on a Connection.

accessToUnderlyingConnectionAllowed

false

控制PoolGuard是否容许获取底层连接(Controls if the PoolGuard allows access to the underlying connection.) 默认false不开启, 这是一个有潜在危险的功能, 不适当的编码会造成伤害.(关闭底层连接或者在守护连接已经关闭的情况下继续使用它).请谨慎使用,并且仅当需要直接访问驱动的特定功能时使用.注意: 不要关闭底层连接, 只能关闭前面的那个. Default is false, it is a potential dangerous operation and misbehaving programs can do harmful things. (closing the underlying or continue using it when the guarded connection is already closed) Be careful and only use when you need direct access to driver specific extensions. NOTE: Do not close the underlying connection, only the original one.

removeAbandoned

false

标记是否删除泄露的连接,如果他们超过了removeAbandonedTimout的限制.如果设置为true, 连接被认为是被泄露并且可以被删除,如果空闲时间超过removeAbandonedTimeout. 设置为true可以为写法糟糕的没有关闭连接的程序修复数据库连接. (Flags to remove abandoned connections if they exceed the removeAbandonedTimout. A connection is considered abandoned and eligible for removal if it has not been used for longer than removeAbandonedTimeout. Setting one or both of these to true can recover db connections from poorly written applications which fail to close connections.)

removeAbandonedTimeout

300

泄露的连接可以被删除的超时值, 单位秒 (Timeout in seconds before an abandoned connection can be removed.)

logAbandoned

false

标记当Statement或连接被泄露时是否打印程序的stack traces日志。被泄露的Statements和连接的日志添加在每个连接打开或者生成新的Statement,因为需要生成stack trace。(Flag to log stack traces for application code which abandoned a Statement or Connection. Logging of abandoned Statements and Connections adds overhead for every Connection open or new Statement because a stack trace has to be generated.)

abandonedUsageTracking

false

如果为true, 那么连接池会记录每个方法调用时候的堆栈信息以及废弃连接的调试信息(If true, the connection pool records a stack trace every time a method is called on a pooled connection and retains the most recent stack trace to aid debugging of abandoned connections. There is significant overhead added by setting this to true.)