我在下面发布了日志的一小部分，如果有人可以解码以下内容，我将不胜感激：
我具有以下C3PO配置：
c3p0.minPoolSize=10
c3p0.maxPoolSize=40
c3p0.acquireIncrement=5
c3p0.maxIdleTime=1800
c3p0.maxStatements=50
c3p0.idleConnectionTestPeriod=180
这是日志：
09-02@12:28:43 WARN ThreadPoolAsynchronousRunner [Timer-0] - com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@700ec336 -- APPARENT DEADLOCK!!! Creating emergency threads for unassigned pending tasks!
09-02@12:28:43 WARN ThreadPoolAsynchronousRunner [Timer-0] - com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@700ec336 -- APPARENT DEADLOCK!!! Complete Status:
Managed Threads: 3
Active Threads: 3
Active Tasks:
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StatementCloseTask@34ac7f2c (com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#1)
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StatementCloseTask@28d13cb8 (com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#0)
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StatementCloseTask@40e968f7 (com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#2)
Pending Tasks:
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StatementCloseTask@1bea516c
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StmtAcquireTask@348797c5
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StatementCloseTask@31fd2174
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StmtAcquireTask@619f604f
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StmtAcquireTask@266c149b
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StmtAcquireTask@1bcdfd2
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StatementCloseTask@170a54e2
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StmtAcquireTask@274acd3f
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StatementCloseTask@1fe8f740
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StmtAcquireTask@77c09b1d
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StatementCloseTask@607ca57
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StmtAcquireTask@697518d8
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StatementCloseTask@6b242ff
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StatementCloseTask@214c76c8
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StmtAcquireTask@230a558c
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StmtAcquireTask@7b766c4c
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StatementCloseTask@1bc030e7
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StatementCloseTask@66ca9bec
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StatementCloseTask@7fc2d7ac
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StatementCloseTask@50dd9ebb
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StmtAcquireTask@5e03077
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StmtAcquireTask@418dd7a4
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StatementCloseTask@4748719b
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StatementCloseTask@651a9bac
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StmtAcquireTask@35e26d0f
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StmtAcquireTask@24660f6c
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StatementCloseTask@287e8e1f
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StmtAcquireTask@ca4a9fe
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StmtAcquireTask@e94692e
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StmtAcquireTask@3185527c
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StmtAcquireTask@27ea644a
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@d5e4abf
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StmtAcquireTask@297d4874
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@601fccf3
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StmtAcquireTask@47c896d2
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StmtAcquireTask@4225d9cf
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@42fec6f6
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StmtAcquireTask@64b862d6
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@5610343
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@241d2677
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StmtAcquireTask@75c86126
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StmtAcquireTask@36624233
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StmtAcquireTask@6ce83e29
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@3492d9b
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@39511ccc
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@7c39b279
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StmtAcquireTask@2ff465a6
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@563d8de2
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@632e1ca9
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@685bce1d
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@63390771
com.mchange.v2.resourcepool.BasicResourcePool$1RefurbishCheckinResourceTask@3517be9b
Pool thread stack traces:
Thread[com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#0,5,main]
com.mysql.jdbc.StatementImpl.close(StatementImpl.java:575)
com.mchange.v1.db.sql.StatementUtils.attemptClose(StatementUtils.java:41)
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StatementCloseTask.run(GooGooStatementCache.java:404)
com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547)
Thread[com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#2,5,main]
com.mysql.jdbc.StatementImpl.close(StatementImpl.java:575)
com.mchange.v1.db.sql.StatementUtils.attemptClose(StatementUtils.java:41)
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StatementCloseTask.run(GooGooStatementCache.java:404)
com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547)
Thread[com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#1,5,main]
com.mysql.jdbc.StatementImpl.close(StatementImpl.java:575)
com.mchange.v1.db.sql.StatementUtils.attemptClose(StatementUtils.java:41)
com.mchange.v2.c3p0.stmt.GooGooStatementCache$1StatementCloseTask.run(GooGooStatementCache.java:404)
com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547)
一些有关明显死锁的信息将不胜感激。
答案 0 :(得分：1)
线程池包含3个线程。 （“托管线程”）。他们三个都处于“活动状态”，试图完成一项任务。 （“活动线程”），没有准备就绪的休眠线程。列出了任务。它们都是缓存语句关闭任务。
线程池中的所有任务长时间保持不变后，将触发APPARENT DEADLOCK。 c3p0（实际上是其下的线程池库）最终假设，如果没有任务在池中完成，则该池是死锁的。库interrupt（）s然后丢弃这些线程，并用新线程替换它们，以便其他任务（您的任务积压很长，“待处理任务”）可以尝试运行。
对于您来说，这个问题是众所周知的。如果某些JDBC驱动程序的Statement.close()操作正在使用其父级Connection，则可能会死锁。对于这些（通常不合规格的）驱动程序，c3p0实现了谨慎的Statement关闭策略，其中Statement的破坏是tasked asynchronously and only performed when the parent Connection is known not to be in use。
TL; DR：将statementCacheNumDeferredCloseThreads设置为1。
c3p0.statementCacheNumDeferredCloseThreads=1