c3p0 no bug but the windows xp have

5月30日，用了一天的时间在找一个c3p0的bug,但没有找到。31日突然想起来可能是某个原因，于是配置环境->运行，OK 问题解决。

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经过：最近做了一个SSH2项目，想在项目中使用c3p0连接池，于是就在本地机搭起了项目，配好了spring管理的连接池c3p0,将项目中用到的mysql数据库放在vmware虚拟机中运行。

可是运行项目的时候，报错，但数据库表却能够生成。
此时，我的主机操作系统是windows xp ,数据库服务器的操作系统也是windows xp.数据库mysql 5.0.22 ,所用用户test1的远程权限已经开通。

报错信息如下：

2010-05-30 12:07:19,046 INFO [org.hibernate.tool.hbm2ddl.SchemaUpdate] - Running hbm2ddl schema update
2010-05-30 12:07:19,046 INFO [org.hibernate.tool.hbm2ddl.SchemaUpdate] - fetching database metadata
2010-05-30 12:07:32,875 WARN [com.mchange.v2.async.ThreadPoolAsynchronousRunner] - com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@18105e8 -- [color=red]APPARENT DEADLOCK!!! Creating emergency threads for unassigned pending tasks![/color]
2010-05-30 12:07:32,875 WARN [com.mchange.v2.async.ThreadPoolAsynchronousRunner] - com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@18105e8 -- APPARENT DEADLOCK!!! Complete Status: 
	Managed Threads: 3
	Active Threads: 3
	Active Tasks: 
		com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask@16d8196 (C3P0PooledConnectionPoolManager-Helper Thread-#2)
		com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask@56b93a (C3P0PooledConnectionPoolManager-Helper Thread-#0)
		com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask@19abd2b (C3P0PooledConnectionPoolManager-Helper Thread-#1)
	Pending Tasks: 
		com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask@1f98d58
		com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask@aea710
		com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask@5a2eaa
		com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask@adae91
		com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask@9fe84e
		com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask@4c71d2
		com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@c4bc34
Pool thread stack traces:
	Thread[C3P0PooledConnectionPoolManager-Helper Thread-#2,5,main]
		java.net.SocketInputStream.socketRead0(Native Method)
		java.net.SocketInputStream.read(SocketInputStream.java:129)
		com.mysql.jdbc.util.ReadAheadInputStream.fill(ReadAheadInputStream.java:114)
		com.mysql.jdbc.util.ReadAheadInputStream.readFromUnderlyingStreamIfNecessary(ReadAheadInputStream.java:161)
		com.mysql.jdbc.util.ReadAheadInputStream.read(ReadAheadInputStream.java:189)
		com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:2500)
		com.mysql.jdbc.MysqlIO.readPacket(MysqlIO.java:600)
		com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1079)
		com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2186)
		com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:787)
		com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:49)
		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:409)
		com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:357)
		com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:285)
		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:152)
		com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1074)
		com.mchange.v2.resourcepool.BasicResourcePool.doAcquireAndDecrementPendingAcquiresWithinLockOnSuccess(BasicResourcePool.java:1061)
		com.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.java:32)
		com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask.run(BasicResourcePool.java:1796)
		com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:620)
	Thread[C3P0PooledConnectionPoolManager-Helper Thread-#1,5,main]
		java.net.SocketInputStream.socketRead0(Native Method)
		java.net.SocketInputStream.read(SocketInputStream.java:129)
		com.mysql.jdbc.util.ReadAheadInputStream.fill(ReadAheadInputStream.java:114)
		com.mysql.jdbc.util.ReadAheadInputStream.readFromUnderlyingStreamIfNecessary(ReadAheadInputStream.java:161)
		com.mysql.jdbc.util.ReadAheadInputStream.read(ReadAheadInputStream.java:189)
		com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:2500)
		com.mysql.jdbc.MysqlIO.readPacket(MysqlIO.java:600)
		com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1079)
		com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2186)
		com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:787)
		com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:49)
		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:409)
		com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:357)
		com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:285)
		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:152)
		com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1074)
		com.mchange.v2.resourcepool.BasicResourcePool.doAcquireAndDecrementPendingAcquiresWithinLockOnSuccess(BasicResourcePool.java:1061)
		com.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.java:32)
		com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask.run(BasicResourcePool.java:1796)
		com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:620)
	Thread[C3P0PooledConnectionPoolManager-Helper Thread-#0,5,main]
		java.net.SocketInputStream.socketRead0(Native Method)
		java.net.SocketInputStream.read(SocketInputStream.java:129)
		com.mysql.jdbc.util.ReadAheadInputStream.fill(ReadAheadInputStream.java:114)
		com.mysql.jdbc.util.ReadAheadInputStream.readFromUnderlyingStreamIfNecessary(ReadAheadInputStream.java:161)
		com.mysql.jdbc.util.ReadAheadInputStream.read(ReadAheadInputStream.java:189)
		com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:2500)
		com.mysql.jdbc.MysqlIO.readPacket(MysqlIO.java:600)
		com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1079)
		com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2186)
		com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:787)
		com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:49)
		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:409)
		com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:357)
		com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:285)
		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:152)
		com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1074)
		com.mchange.v2.resourcepool.BasicResourcePool.doAcquireAndDecrementPendingAcquiresWithinLockOnSuccess(BasicResourcePool.java:1061)
		com.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.java:32)
		com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask.run(BasicResourcePool.java:1796)
		com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:620)


2010-05-30 12:07:32,921 INFO [org.hibernate.tool.hbm2ddl.SchemaUpdate] - updating schema
2010-05-30 12:07:33,015 INFO [org.hibernate.tool.hbm2ddl.TableMetadata] - table found: testDB.employee
2010-05-30 12:07:33,015 INFO [org.hibernate.tool.hbm2ddl.TableMetadata] - columns: [username, gender, password]
2010-05-30 12:07:33,015 INFO [org.hibernate.tool.hbm2ddl.TableMetadata] - foreign keys: []
2010-05-30 12:07:33,015 INFO [org.hibernate.tool.hbm2ddl.TableMetadata] - indexes: [primary]
2010-05-30 12:07:33,015 INFO [org.hibernate.tool.hbm2ddl.SchemaUpdate] - schema update complete
2010-05-30 12:07:33,125 INFO [org.springframework.orm.hibernate3.HibernateTransactionManager] - Using DataSource [com.mchange.v2.c3p0.ComboPooledDataSource [ acquireIncrement -> 5, acquireRetryAttempts -> 30, acquireRetryDelay -> 1000, autoCommitOnClose -> false, automaticTestTable -> null, breakAfterAcquireFailure -> false, checkoutTimeout -> 0, connectionCustomizerClassName -> null, connectionTesterClassName -> com.mchange.v2.c3p0.impl.DefaultConnectionTester, dataSourceName -> 1hge13i881s7ax0b2yw8gy|17494c8, debugUnreturnedConnectionStackTraces -> false, description -> null, driverClass -> org.gjt.mm.mysql.Driver, factoryClassLocation -> null, forceIgnoreUnresolvedTransactions -> false, identityToken -> 1hge13i881s7ax0b2yw8gy|17494c8, idleConnectionTestPeriod -> 60, initialPoolSize -> 10, jdbcUrl -> jdbc:mysql://192.168.1.165:3306/testDB?useUnicode=true&characterEncoding=UTF-8, maxAdministrativeTaskTime -> 0, maxConnectionAge -> 0, maxIdleTime -> 60, maxIdleTimeExcessConnections -> 0, maxPoolSize -> 30, maxStatements -> 0, maxStatementsPerConnection -> 0, minPoolSize -> 5, numHelperThreads -> 3, numThreadsAwaitingCheckoutDefaultUser -> 0, preferredTestQuery -> null, properties -> {user=******, password=******}, propertyCycle -> 0, statementCacheNumDeferredCloseThreads -> 0, statementDestroyerNumActiveThreads -> -1, statementDestroyerNumConnectionsInUseAllUsers -> -1, statementDestroyerNumConnectionsInUseDefaultUser -> -1, statementDestroyerNumConnectionsWithDeferredDestroyStatementsAllUsers -> -1, statementDestroyerNumConnectionsWithDeferredDestroyStatementsDefaultUser -> -1, statementDestroyerNumDeferredDestroyStatementsAllUsers -> -1, statementDestroyerNumDeferredDestroyStatementsDefaultUser -> -1, statementDestroyerNumIdleThreads -> -1, statementDestroyerNumTasksPending -> -1, statementDestroyerNumThreads -> -1, testConnectionOnCheckin -> false, testConnectionOnCheckout -> false, unreturnedConnectionTimeout -> 0, usesTraditionalReflectiveProxies -> false ]] of Hibernate SessionFactory for HibernateTransactionManager

不管怎样调整c3p0的运行参数，都没办法找到错误的所在，表面看就是无法获得连接。
但我把项目拷贝到数据库服务器上，让程序和数据库处于同一机器上时，再运行，错误没有了，运行速度很快。

从上面的情况来看，有两种可能：一是网络这个环节上出了问题，不能正常处理数据库的请求数据。二是c3p0有问题，在本地机可以很好地运行，在网络协议上的处理上有不正常的的地方。但这两种可能我都觉得不太可能，因为无论是网络还是c3p0都不是一天两天的东西了，存在这种低级问题的可能很小。

可问题依然存在，夜不能寐....。

第二日，猛然想起来，记得当年windows xp sp3发布以后，曾经限制过TCP/IP的连接，会不会是这个东东在作怪呢？赶紧在vmware 的windows 2003 server服务器上安装上mysql 5.0.22,配置好帐号的远程访问权限。项目运行OK

至此，问题终于得到解决。

原因：因为windows xp限制了TCP/IP的并发数量，如果我们用xp做服务器，单机开发是没有问题的，这时，我们登录数据库都是一个用户，一个连接。但用了连接池以后，就是一个用户，多个连接了，这时候xp的限制作用就生效了。
所以，在项目中使用数据库服务器的时候，其操作系统最好选择server版本的，否则，出现问题很不好查。

我在网上查错误的时候，发现好多人都说这是c3p0的bug,在此特更正一下，出现这种错误，多数是环境问题，尤其是windows xp作服务器的情况下。
C3p0 no bug but the windows xp have

顺便说一下，c3p0的0.9.2-pre1版也在5月27日发布了。