Mysql 5 + hibernate3 采用c3p0连接池
WARN [ThreadPoolAsynchronousRunner] - com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@a37c6a -- APPARENT DEADLOCK!!! Creating emergency threads for unassigned pending tasks!
WARN [ThreadPoolAsynchronousRunner] - com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@a37c6a -- APPARENT DEADLOCK!!! Complete Status:
    Managed Threads: 3
    Active Threads: 3
    Active Tasks:
        com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@7881db (com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#1)
        com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@1956391 (com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#0)
        com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@bbf7aa (com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#2)
    Pending Tasks:
        com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@80ed90
        com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@6cc2a4
Pool thread stack traces:
    Thread[com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#1,5,main]
        java.lang.Thread.sleep(Native Method)
        com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1805)
        com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547)
    Thread[com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#0,5,main]
        java.lang.Thread.sleep(Native Method)
        com.mysql.jdbc.ConnectionImpl.connectWithRetries(ConnectionImpl.java:2229)
        com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2159)
        com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:792)
        com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
        sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
        sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
        sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
        java.lang.reflect.Constructor.newInstance(Constructor.java:513)
        com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
        com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:381)
        com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:305)
        com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:135)
        com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:182)
        com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:171)
        com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:137)
        com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1014)
        com.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.java:32)
        com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1810)
        com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547)
    Thread[com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#2,5,main]
        java.lang.Thread.sleep(Native Method)
        com.mysql.jdbc.ConnectionImpl.connectWithRetries(ConnectionImpl.java:2229)
        com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2159)
        com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:792)
        com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
        sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
        sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
        sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
        java.lang.reflect.Constructor.newInstance(Constructor.java:513)
        com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
        com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:381)
        com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:305)
        com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:135)
        com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:182)
        com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:171)
        com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:137)
        com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1014)
        com.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.java:32)
        com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1810)
        com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547)

 http://topic.csdn.net/u/20090927/13/e73eb214-1082-4f10-894f-cc4b83a0960d.html
http://www.iteye.com/topic/22160
http://www.mchange.com/projects/c3p0/index.html#maxStatementsPerConnection