C3p0的问题：testConnectionOnCheckin -＞ false, testConnectionOnCheckout -＞ false

环境： 使用云服务器搭建CDH的时候报错

问题： 如下

2020-06-07 19:21:32,847 INFO main:com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource: Initializingc3p0 pool... com.mchange.v2.c3p0.PoolBackedDataSource@8f7cc46f [ connectionPoolDataSource -> com.mchange.v2.c3p0.WrapperConnectionPoolDataSource@d4cd6cc2 [ acquireIncrement -> 3, acquireRetryAttempts -> 5, acquireRetryDelay -> 1000, autoCommitOnClose -> false, automaticTestTable -> null, breakAfterAcquireFailure -> false, checkoutTimeout -> 20000, connectionCustomizerClassName -> null, connectionTesterClassName -> com.mchange.v2.c3p0.impl.DefaultConnectionTester, debugUnreturnedConnectionStackTraces -> false, factoryClassLocation -> null, forceIgnoreUnresolvedTransactions -> false, identityToken -> 12s31qqaa13jja6k18x413m|64f16277, idleConnectionTestPeriod -> 300, initialPoolSize -> 5, maxAdministrativeTaskTime -> 0, maxConnectionAge -> 0, maxIdleTime -> 0, maxIdleTimeExcessConnections -> 0, maxPoolSize -> 50, maxStatements -> 2500, maxStatementsPerConnection -> 0, minPoolSize -> 5, nestedDataSource -> com.mchange.v2.c3p0.DriverManagerDataSource@cb1381b [ description -> null, driverClass -> null, factoryClassLocation -> null, identityToken -> 12s31qqaa13jja6k18x413m|7c2b58c0, jdbcUrl -> jdbc:mysql://bdp_CDH63_01:3306/cmf?useUnicode=true&characterEncoding=UTF-8, properties -> {user=******, password=******} ], preferredTestQuery -> null, propertyCycle -> 0, statementCacheNumDeferredCloseThreads -> 0, testConnectionOnCheckin -> false, testConnectionOnCheckout -> false, unreturnedConnectionTimeout -> 0, usesTraditionalReflectiveProxies -> false; userOverrides: {} ], dataSourceName -> null, factoryClassLocation -> null, identityToken -> 12s31qqaa13jja6k18x413m|706eab5d, numHelperThreads -> 3 ]
2020-06-07 19:21:52,846 WARN C3P0PooledConnectionPoolManager[identityToken->12s31qqaa13jja6k18x413m|706eab5d]-AdminTaskTimer:com.mchange.v2.async.ThreadPoolAsynchronousRunner: com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@6c01fac -- APPARENT DEADLOCK!!! Creating emergency threads forunassigned pending tasks!
2020-06-07 19:21:52,848 WARN C3P0PooledConnectionPoolManager[identityToken->12s31qqaa13jja6k18x413m|706eab5d]-AdminTaskTimer:com.mchange.v2.async.ThreadPoolAsynchronousRunner: com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@6c01fac -- APPARENT DEADLOCK!!!

问题分析：

jdbcUrl -> jdbc:mysql://bdp_CDH63_01:3306/cmf?useUnicode=true&characterEncoding=UTF-8, properties -> {user=******, password=******} ], preferredTestQuery -> null, propertyCycle -> 0, statementCacheNumDeferredCloseThreads -> 0, testConnectionOnCheckin -> false

根据上边的内容，尝试了一下删除重建，就好了

解决方案：删库重建