C3p0 APPARENT DEADLOCK异常

Question

我在Tomcat日志中不断收到此异常:

com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector run
WARNING: com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@76b28200 -- APPARENT DEADLOCK!!! Creating emergency threads for unassigned pending tasks!
com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector run
WARNING: com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@76b28200 -- APPARENT DEADLOCK!!! Complete Status: 
    Managed Threads: 3
    Active Threads: 3
    Active Tasks: 
        com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@1201fd18 (com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#1)
        com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@408f3be4 (com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#0)
        com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@7ba516d8 (com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#2)
    Pending Tasks: 
        com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@137efe53
        com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@766b0524
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.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$PoolThread-#2,5,main]
        java.lang.Thread.sleep(Native Method)
        com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1805)
        com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547)

我正在使用Hibernate 3.6.2和C3P0 0.9.1.2与MySQL.经过几个小时的Google搜索,这个APPARENT DEADLOCK异常似乎通常与准备好的语句缓存相关联.这是我的hibernate.cfg.xml中的C3P0配置:

<propertyname="connection.provider_class">org.hibernate.connection.C3P0ConnectionProvider</property>
<property name="hibernate.c3p0.acquire_increment">5</property>
<property name="hibernate.c3p0.min_size">5</property>
<property name="hibernate.c3p0.max_size">60</property>
<property name="hibernate.c3p0.idle_test_period">120</property>
<property name="hibernate.c3p0.timeout">180</property>              
<property name="hibernate.c3p0.max_statements">0</property>

我没有做任何声明缓存.任何有关错误的提示将不胜感激.

Answer 1

交易的任务是连接获取任务.也就是说,c3p0正试图从您的数据库中获取新的连接,并且这些连接获取尝试需要很长时间.

我要做的第一件事就是升级到0.9.2.1,它在采集尝试有时会失败的情况下,有更好的方法来执行一轮连接采集.

如果这不能解决您的问题,那么您需要弄清楚为什么c3p0尝试获取连接的时间长达很长时间:既没有成功也没有失败.