C3P0 老是报错，求大神！！！

Louistao 2013-02-17 02:53:55 


[2013-02-14 20:37:46] WARN  [com.mchange.v2.resourcepool.BasicResourcePool] - Failed to destroy resource: com.mchange.v2.c3p0.impl.NewPooledConnection@14c7262

java.util.ConcurrentModificationException

	at java.util.HashMap$HashIterator.nextEntry(HashMap.java:793)

	at java.util.HashMap$KeyIterator.next(HashMap.java:828)

	at com.mysql.jdbc.Connection.closeAllOpenStatements(Connection.java:2191)

	at com.mysql.jdbc.Connection.realClose(Connection.java:4777)

	at com.mysql.jdbc.Connection.close(Connection.java:2172)

	at com.mchange.v2.c3p0.impl.NewPooledConnection.close(NewPooledConnection.java:474)

	at com.mchange.v2.c3p0.impl.NewPooledConnection.close(NewPooledConnection.java:191)

	at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.destroyResource(C3P0PooledConnectionPool.java:470)

	at com.mchange.v2.resourcepool.BasicResourcePool$1DestroyResourceTask.run(BasicResourcePool.java:964)

	at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547)


[2013-02-15 11:48:15] WARN  [com.mchange.v2.resourcepool.BasicResourcePool] - com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@11079b5 -- Acquisition Attempt Failed!!! Clearing pending acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of allowed acquisition attempts (30). Last acquisition attempt exception: 

com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception: 



** BEGIN NESTED EXCEPTION ** 



java.net.SocketException

MESSAGE: java.net.SocketException: No buffer space available (maximum connections reached?): connect



STACKTRACE:



java.net.SocketException: java.net.SocketException: No buffer space available (maximum connections reached?): connect

	at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:156)

	at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:276)

	at com.mysql.jdbc.Connection.createNewIO(Connection.java:2666)

	at com.mysql.jdbc.Connection.<init>(Connection.java:1531)

	at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:266)

	at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:135)

	at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:182)

	at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:171)

	at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:137)

	at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1014)

	at com.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.java:32)

	at com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1810)

	at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547)





** END NESTED EXCEPTION **







Last packet sent to the server was 0 ms ago.

	at com.mysql.jdbc.Connection.createNewIO(Connection.java:2741)

	at com.mysql.jdbc.Connection.<init>(Connection.java:1531)

	at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:266)

	at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:135)

	at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:182)

	at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:171)

	at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:137)

	at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1014)

	at com.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.java:32)

	at com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1810)

	at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547)

[2013-02-15 11:49:43] WARN  [com.mchange.v2.async.ThreadPoolAsynchronousRunner] - com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@9184d1 -- APPARENT DEADLOCK!!! Creating emergency threads for unassigned pending tasks!

[2013-02-15 11:49:44] WARN  [com.mchange.v2.async.ThreadPoolAsynchronousRunner] - com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@9184d1 -- APPARENT DEADLOCK!!! Complete Status: 

	Managed Threads: 3

	Active Threads: 0

	Active Tasks: 

	Pending Tasks: 

		com.mchange.v2.resourcepool.BasicResourcePool$AsyncTestIdleResourceTask@1217953

		com.mchange.v2.resourcepool.BasicResourcePool$AsyncTestIdleResourceTask@a45b9a

		com.mchange.v2.resourcepool.BasicResourcePool$AsyncTestIdleResourceTask@79e819

		com.mchange.v2.resourcepool.BasicResourcePool$AsyncTestIdleResourceTask@174e98f

		com.mchange.v2.resourcepool.BasicResourcePool$AsyncTestIdleResourceTask@91be7f

		com.mchange.v2.resourcepool.BasicResourcePool$AsyncTestIdleResourceTask@719386

		com.mchange.v2.resourcepool.BasicResourcePool$AsyncTestIdleResourceTask@8c7d1c

Pool thread stack traces:

	Thread[com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#1,5,]

	Thread[com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#0,5,]

	Thread[com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#2,5,]
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Louistao 2013-02-17
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引用 10 楼 fangmingshijie 的回复:
如果同时访问，数据访问量比较大的话，会比较慢。
大侠，有空的话加下我Q：812579512，求指点
花谢尊前不敢香 2013-02-17
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如果同时访问，数据访问量比较大的话，会比较慢。
Louistao 2013-02-17
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引用 8 楼 fangmingshijie 的回复:
不用，有自动关闭机制。
好的，还有个问题，请问假如我有三个程序里面都用到了c3p0，三个程序都放在了一个服务器的Tomcat下，这样做的话，有什么地方需求注意的吗？
花谢尊前不敢香 2013-02-17
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不用，有自动关闭机制。
Louistao 2013-02-17
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引用 6 楼 fangmingshijie 的回复:
Java code?12345678<property name="minPoolSize" value="1" /><property name="maxPoolSize" value="300" /><property name="maxIdleTime" value="60" /><property name="acquireIncrement" value="5"……
WARN之类的警告都不会报吗？还有一个问题想请教一下，请问大侠用过mybatis吗？ 我用spring+ mybatis 需要手动的去关闭连接吗
花谢尊前不敢香 2013-02-17
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<property name="minPoolSize" value="1" />
<property name="maxPoolSize" value="300" />
<property name="maxIdleTime" value="60" />
<property name="acquireIncrement" value="5" />
<property name="initialPoolSize" value="1" />
<property name="idleConnectionTestPeriod" value="60" />

我设置成这样就跑的很好。
Louistao 2013-02-17
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引用 3 楼 crlystaldong 的回复:
<property name="maxIdleTime"> <value>300</value> </property> 好像是这个，保持连接时间应该设置大点
请问下如果maxIdleTime设置成300秒会影响到那些方面？
Louistao 2013-02-17
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引用 2 楼 fangmingshijie 的回复:
看下你的配置文件，最大连接池多少
是mysql的最大连接数吗？ mysql的最大连接数为800
小V小V志 2013-02-17
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<property name="maxIdleTime"> <value>300</value> </property> 好像是这个，保持连接时间应该设置大点
花谢尊前不敢香 2013-02-17
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看下你的配置文件，最大连接池多少
Louistao 2013-02-17
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我的配置是这样的： 
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"
		destroy-method="close">
		<property name="driverClass">
			<value>com.mysql.jdbc.Driver</value>
		</property>
		<property name="jdbcUrl">
			<value>jdbc:mysql://127.0.0.1:3306/smsdb?useUnicode=true&characterEncoding=UTF-8& </value>
		</property>
		<property name="user">
			<value>root</value>
		</property>
		<property name="password">
			<value>123456</value>
		</property>
		<!--连接池中保留的最小连接数。 -->
		<property name="minPoolSize">
			<value>10</value>
		</property>

		<!--连接池中保留的最大连接数。Default: 15 -->
		<property name="maxPoolSize">
			<value>35</value>
		</property>

		<!--初始化时获取的连接数，取值应在minPoolSize与maxPoolSize之间。Default: 3 -->
		<property name="initialPoolSize">
			<value>15</value>
		</property>

		<!--最大空闲时间,60秒内未使用则连接被丢弃。若为0则永不丢弃。Default: 0 -->
		<property name="maxIdleTime">
			<value>300</value>
		</property>

		<!--当连接池中的连接耗尽的时候c3p0一次同时获取的连接数。Default: 3 -->
		<property name="acquireIncrement">
			<value>0</value>
		</property>

		<!--JDBC的标准参数，用以控制数据源内加载的PreparedStatements数量。但由于预缓存的statements 属于单个connection而不是整个连接池。所以设置这个参数需要考虑到多方面的因素。 
			如果maxStatements与maxStatementsPerConnection均为0，则缓存被关闭。Default: 0 -->
		<property name="maxStatements">
			<value>0</value>
		</property>

		<!--每60秒检查所有连接池中的空闲连接。Default: 0 -->
		<property name="idleConnectionTestPeriod">
			<value>100</value>
		</property>

	</bean>
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分享一下我老师大神的人工智能教程！零基础，通俗易懂！http://blog.csdn.net/jiangjunshow也欢迎大家转载本篇文章。分享知识，造福人民，实现我们中华民族伟大复兴！&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; paip.提升稳定性-
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