C3P0 老是报错，求大神！！！

Question

[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?): connectSTACKTRACE: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,]c3p0

Answer 1

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&amp;characterEncoding=UTF-8&amp; </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>

  

Answer 2

<property name="maxIdleTime">
            <value>300</value>
        </property>
好像是这个，保持连接时间应该设置大点

Answer 3

是mysql的最大连接数吗？ mysql的最大连接数为800

Answer 4

请问下如果maxIdleTime设置成300秒会影响到那些方面？

Answer 5

<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。

Answer 6

 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

Answer 7

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？