HikariCP 线程未被释放 - 如何排除故障？

Question

我正在尝试将应用程序从 Hibernate 3.6.10.Final（使用 c3p0 连接池）迁移到 4.3.11.Final（对于 CP，HikariCP-2.4.3）。

自迁移以来应用程序逻辑没有改变，但我认为线程现在没有得到重用。

有什么建议从哪里开始解决这个问题？

老persistence.properties:

hibernate.connection.url=jdbc:mysql://localhost:3306/%S?useDynamicCharsetInfo=false
hibernate.connection.driver_class=org.mariadb.jdbc.Driver
hibernate.connection.password=XXXXX
hibernate.connection.username= XXXXX
hibernate.dialect=org.hibernate.dialect.MySQL5InnoDBDialect
  hibernate.connection.provider_class=org.hibernate.connection.C3P0ConnectionProvider
hibernate.c3p0.min_size=5
hibernate.c3p0.max_size=100
hibernate.c3p0.timeout=200
hibernate.c3p0.checkoutTimeout=10000
hibernate.c3p0.maxStatementsPerConnection=40
hibernate.c3p0.idle_test_period=100
hibernate.c3p0.numHelperThreads=3
preferredTestQuery=SELECT 1
unreturnedConnectionTimeout=1080
debugUnreturnedConnectionStackTraces=false

新的 persistence.properties 将 c3p0 替换为：

hibernate.connection.provider_class=com.zaxxer.hikari.hibernate.HikariConnectionProvider
hibernate.hikari.dataSource.url=jdbc:mysql://localhost:3306/%S?useDynamicCharsetInfo=false
hibernate.hikari.dataSource.user= XXXXX
hibernate.hikari.dataSource.password= XXXXX
hibernate.hikari.maximumPoolSize=100

但是该应用程序运行了一段时间，然后所有线程似乎都处于活动状态并且在我重新启动该应用程序之前没有释放，例如

2016-05-12 16:36:02,915 DEBUG [Hikari housekeeper (pool HikariPool-0)] hikari.pool.HikariPool.logPoolState():383 - After cleanup    pool HikariPool-0 stats (total=100, active=100, idle=0, waiting=2)

我看到这些错误：

DEBUG [Hikari housekeeper (pool HikariPool-0)] hikari.pool.HikariPool.logPoolState():383 - After cleanup    pool HikariPool-0 stats (total=100, active=100, idle=0, waiting=5)
Caused by: java.sql.SQLTransientConnectionException: HikariPool-0 - Connection is not available, request timed out after 30000ms.
    at com.zaxxer.hikari.pool.HikariPool.getConnection(HikariPool.java:195) ~[HikariCP-2.4.3.jar:?]
    at com.zaxxer.hikari.pool.HikariPool.getConnection(HikariPool.java:147) ~[HikariCP-2.4.3.jar:?]
    at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:83) ~[HikariCP-2.4.3.jar:?]
    at com.zaxxer.hikari.hibernate.HikariConnectionProvider.getConnection(HikariConnectionProvider.java:106) ~[HikariCP-2.4.3.jar:?]
    at org.hibernate.internal.AbstractSessionImpl$NonContextualJdbcConnectionAccess.obtainConnection(AbstractSessionImpl.java:380) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
    at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.obtainConnection(LogicalConnectionImpl.java:228) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
    at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.getConnection(LogicalConnectionImpl.java:171) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
    at org.hibernate.engine.transaction.internal.jdbc.JdbcTransaction.doBegin(JdbcTransaction.java:67) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
    at org.hibernate.engine.transaction.spi.AbstractTransactionImpl.begin(AbstractTransactionImpl.java:162) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
    at org.hibernate.internal.SessionImpl.beginTransaction(SessionImpl.java:1471) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
    at org.hibernate.jpa.internal.TransactionImpl.begin(TransactionImpl.java:61) ~[hibernate-entitymanager-4.3.11.Final.jar:4.3.11.Final]
    ... 16 more

或者我看到泄漏检测：

2016-05-13 09:48:06,819  WARN [Hikari housekeeper (pool HikariPool-0)] hikari.pool.ProxyLeakTask.run():87 - Connection leak detection triggered for connection org.mariadb.jdbc.MySQLConnection@4f7e08a, stack trace follows
java.lang.Exception: Apparent connection leak detected
        at com.zaxxer.hikari.hibernate.HikariConnectionProvider.getConnection(HikariConnectionProvider.java:106) ~[HikariCP-2.4.3.jar:?]
        at org.hibernate.internal.AbstractSessionImpl$NonContextualJdbcConnectionAccess.obtainConnection(AbstractSessionImpl.java:380) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
        at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.obtainConnection(LogicalConnectionImpl.java:228) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
        at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.getConnection(LogicalConnectionImpl.java:171) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
        at org.hibernate.engine.jdbc.internal.StatementPreparerImpl.connection(StatementPreparerImpl.java:63) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
        at org.hibernate.engine.jdbc.internal.StatementPreparerImpl.doPrepare(StatementPreparerImpl.java:162) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
        at org.hibernate.engine.jdbc.internal.StatementPreparerImpl$StatementPreparationTemplate.prepareStatement(StatementPreparerImpl.java:186) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
        at org.hibernate.engine.jdbc.internal.StatementPreparerImpl.prepareQueryStatement(StatementPreparerImpl.java:160) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
        at org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1885) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
        at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1862) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
        at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1839) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
        at org.hibernate.loader.Loader.doQuery(Loader.java:910) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
        at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:355) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
        at org.hibernate.loader.Loader.doList(Loader.java:2554) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
        at org.hibernate.loader.Loader.doList(Loader.java:2540) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
        at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2370) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
        at org.hibernate.loader.Loader.list(Loader.java:2365) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
        at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:497) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
        at org.hibernate.hql.internal.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:387) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
        at org.hibernate.engine.query.spi.HQLQueryPlan.performList(HQLQueryPlan.java:236) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
        at org.hibernate.internal.SessionImpl.list(SessionImpl.java:1300) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
        at org.hibernate.internal.QueryImpl.list(QueryImpl.java:103) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
        at org.hibernate.jpa.internal.QueryImpl.list(QueryImpl.java:573) ~[hibernate-entitymanager-4.3.11.Final.jar:4.3.11.Final]
        at org.hibernate.jpa.internal.QueryImpl.getResultList(QueryImpl.java:449) ~[hibernate-entitymanager-4.3.11.Final.jar:4.3.11.Final]
// SNIP

代码看起来有点像这样：

import javax.persistence.EntityManager;
import javax.persistence.EntityTransaction;
//SNIP
protected List executeQuery(final String query) {

    final EntityManager entityManager = getEntityManager();
    try {
        return entityManager.createQuery(query).getResultList();
    } finally {
        entityManager.clear();
    }
}

Answer 1

C3P0 正在使用以下方法关闭未返回到池中的连接： unreturnedConnectionTimeout=1080 debugUnreturnedConnectionStackTraces=false

HikariCP 不提供此类属性。您必须确保 'entity manager' 正在关闭从池中借用的连接。

HikariCP 线程未被释放 - 如何排除故障？

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