场景：
一个quartz定时任务，定时调用一个方法，方法里面通过多数据源从三个数据源ds1, ds2, ds3，获取数据，然后将这批数据插入另一个数据源 ds4的表中，再将这批数据从 ds4中查出来进行业务分析， 用的c3p0 连接池，
报错：【下面有贴出来】
同时 数据源 ds1 数据库出现异常，
报错后，数据源 ds1, ds2, ds3 的数据不能同步到 ds4 了，ds4的业务也不在执行，定时任务被挂起..
这种场景 有可能是什么原因 引起定时任务被挂起的啊？
WARN [com.mchange.v2.async.ThreadPoolAsynchronousRunner] - com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@3ee2b918 -- APPARENT DEADLOCK!!! Creating emergency threads for unassigned pending tasks!
[com.mchange.v2.async.ThreadPoolAsynchronousRunner] - com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@3ee2b918 -- APPARENT DEADLOCK!!! Complete Status:
Managed Threads: 3
Active Threads: 3
Active Tasks:
com.mchange.v2.resourcepool.BasicResourcePool$1DestroyResourceTask@16e5f6e9 (com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#0)
com.mchange.v2.resourcepool.BasicResourcePool$1DestroyResourceTask@53b546bd (com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#2)
com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@22374d3a (com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#1)
Pending Tasks:
com.mchange.v2.resourcepool.BasicResourcePool$1DestroyResourceTask@5caf2c62
com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@708b0577
com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@3714015a
Pool thread stack traces:
Thread[com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#0,5,main]
java.net.SocketInputStream.socketRead0(Native Method)
java.net.SocketInputStream.read(SocketInputStream.java:129)
oracle.net.ns.Packet.receive(Unknown Source)
oracle.net.ns.DataPacket.receive(Unknown Source)
oracle.net.ns.NetInputStream.getNextPacket(Unknown Source)
oracle.net.ns.NetInputStream.read(Unknown Source)
oracle.net.ns.NetInputStream.read(Unknown Source)
oracle.net.ns.NetInputStream.read(Unknown Source)
oracle.jdbc.driver.T4CMAREngine.unmarshalUB1(T4CMAREngine.java:1099)
oracle.jdbc.driver.T4CMAREngine.unmarshalSB1(T4CMAREngine.java:1070)
oracle.jdbc.driver.T4C7Ocommoncall.receive(T4C7Ocommoncall.java:106)
oracle.jdbc.driver.T4CConnection.logoff(T4CConnection.java:489)
oracle.jdbc.driver.PhysicalConnection.close(PhysicalConnection.java:1446)
com.mchange.v2.c3p0.impl.NewPooledConnection.close(NewPooledConnection.java:549)
com.mchange.v2.c3p0.impl.NewPooledConnection.close(NewPooledConnection.java:234)
com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.destroyResource(C3P0PooledConnectionPool.java:470)
com.mchange.v2.resourcepool.BasicResourcePool$1DestroyResourceTask.run(BasicResourcePool.java:964)
com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547)
Thread[com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#2,5,main]
java.net.SocketInputStream.socketRead0(Native Method)
java.net.SocketInputStream.read(SocketInputStream.java:129)
oracle.net.ns.Packet.receive(Unknown Source)
oracle.net.ns.DataPacket.receive(Unknown Source)
oracle.net.ns.NetInputStream.getNextPacket(Unknown Source)
oracle.net.ns.NetInputStream.read(Unknown Source)
oracle.net.ns.NetInputStream.read(Unknown Source)
oracle.net.ns.NetInputStream.read(Unknown Source)
oracle.jdbc.driver.T4CMAREngine.unmarshalUB1(T4CMAREngine.java:1099)
oracle.jdbc.driver.T4CMAREngine.unmarshalSB1(T4CMAREngine.java:1070)
oracle.jdbc.driver.T4C7Ocommoncall.receive(T4C7Ocommoncall.java:106)
oracle.jdbc.driver.T4CConnection.logoff(T4CConnection.java:489)
oracle.jdbc.driver.PhysicalConnection.close(PhysicalConnection.java:1446)
com.mchange.v2.c3p0.impl.NewPooledConnection.close(NewPooledConnection.java:549)
com.mchange.v2.c3p0.impl.NewPooledConnection.close(NewPooledConnection.java:234)
com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.destroyResource(C3P0PooledConnectionPool.java:470)
com.mchange.v2.resourcepool.BasicResourcePool$1DestroyResourceTask.run(BasicResourcePool.java:964)
com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547)
Thread[com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#1,5,main]
java.net.SocketInputStream.socketRead0(Native Method)
java.net.SocketInputStream.read(SocketInputStream.java:129)
oracle.net.ns.Packet.receive(Unknown Source)
oracle.net.ns.NSProtocol.connect(Unknown Source)
oracle.jdbc.driver.T4CConnection.connect(T4CConnection.java:1023)
oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:282)
oracle.jdbc.driver.PhysicalConnection.(PhysicalConnection.java:447)
oracle.jdbc.driver.T4CConnection.(T4CConnection.java:165)
oracle.jdbc.driver.T4CDriverExtension.getConnection(T4CDriverExtension.java:35)
oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:839)
com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:134)
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(ThreadPoolAsynchronousRunn
