postgresql HikariCP - 连接不可用

HikariCP - connection is not available

提问by dfche

We have Spring-boot/Hibernate/PostgreSQL application in our project and use Hikari as the connection pool. We keep running into the following problem: after few hours active connections number grows to the limit and we get the errors like this (full stack trace is at the end of the question):

我们的项目中有 Spring-boot/Hibernate/PostgreSQL 应用程序，并使用 Hikari 作为连接池。我们不断遇到以下问题：几个小时后，活动连接数增长到限制，我们得到这样的错误（完整的堆栈跟踪在问题的末尾）：

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:213) ~[HikariCP-2.4.1.jar:na]
    at com.zaxxer.hikari.pool.HikariPool.getConnection(HikariPool.java:163) ~[HikariCP-2.4.1.jar:na]
    at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:85) ~[HikariCP-2.4.1.jar:na]
    at org.hibernate.engine.jdbc.connections.internal.DatasourceConnectionProviderImpl.getConnection(DatasourceConnectionProviderImpl.java:139) ~[hibernate-core-4.3.6.Final.jar:4.3.6.Final]
    at org.hibernate.internal.AbstractSessionImpl$NonContextualJdbcConnectionAccess.obtainConnection(AbstractSessionImpl.java:380) ~[hibernate-core-4.3.6.Final.jar:4.3.6.Final]
    at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.obtainConnection(LogicalConnectionImpl.java:228) ~[hibernate-core-4.3.6.Final.jar:4.3.6.Final]
    ... 126 common frames omitted

Here is the version info:

这是版本信息：

Spring-boot version:   1.2.3.RELEASE
HikariCP version:      2.4.1
Hibernate version:     4.3.6.Final
Postgresql jdbc:       9.3-1102-jdbc41
Server version:        Apache Tomcat/8.0.23
JVM Version:           1.8.0_45-b14

JPA/Hibernate config:

JPA/休眠配置：

jpa:
    database-platform: org.hibernate.dialect.PostgreSQL82Dialect
    database: POSTGRESQL
    openInView: false
    show_sql: false
    generate-ddl: false
    hibernate:
        ddl-auto: none
        naming-strategy: org.hibernate.cfg.EJB3NamingStrategy
    properties:
        hibernate.cache.use_second_level_cache: true
        hibernate.cache.use_query_cache: false
        hibernate.generate_statistics: false
        hibernate.cache.region.factory_class: org.hibernate.cache.ehcache.SingletonEhCacheRegionFactory
        hibernate.enable_lazy_load_no_trans: true
        hibernate.event.merge.entity_copy_observer: allow

HikariCP config:

HikariCP 配置：

2015-10-06 12:26:44,252 DEBUG [localhost-startStop-1] HikariConfig: HikariPool-0 - configuration:
2015-10-06 12:26:44,274 DEBUG [localhost-startStop-1] HikariConfig: allowPoolSuspension.............false
2015-10-06 12:26:44,274 DEBUG [localhost-startStop-1] HikariConfig: autoCommit......................true
2015-10-06 12:26:44,274 DEBUG [localhost-startStop-1] HikariConfig: catalog.........................
2015-10-06 12:26:44,274 DEBUG [localhost-startStop-1] HikariConfig: connectionInitSql...............
2015-10-06 12:26:44,274 DEBUG [localhost-startStop-1] HikariConfig: connectionTestQuery.............
2015-10-06 12:26:44,274 DEBUG [localhost-startStop-1] HikariConfig: connectionTimeout...............30000
2015-10-06 12:26:44,274 DEBUG [localhost-startStop-1] HikariConfig: dataSource......................
2015-10-06 12:26:44,274 DEBUG [localhost-startStop-1] HikariConfig: dataSourceClassName.............org.postgresql.ds.PGSimpleDataSource
2015-10-06 12:26:44,274 DEBUG [localhost-startStop-1] HikariConfig: dataSourceJNDI..................
2015-10-06 12:26:44,274 DEBUG [localhost-startStop-1] HikariConfig: dataSourceProperties............{user=postgres, password=<masked>, databaseName=lms, serverName=*.*.*.*:5432}
2015-10-06 12:26:44,274 DEBUG [localhost-startStop-1] HikariConfig: driverClassName.................
2015-10-06 12:26:44,274 DEBUG [localhost-startStop-1] HikariConfig: healthCheckProperties...........{}
2015-10-06 12:26:44,274 DEBUG [localhost-startStop-1] HikariConfig: healthCheckRegistry.............
2015-10-06 12:26:44,274 DEBUG [localhost-startStop-1] HikariConfig: idleTimeout.....................30000
2015-10-06 12:26:44,275 DEBUG [localhost-startStop-1] HikariConfig: initializationFailFast..........true
2015-10-06 12:26:44,275 DEBUG [localhost-startStop-1] HikariConfig: isolateInternalQueries..........false
2015-10-06 12:26:44,275 DEBUG [localhost-startStop-1] HikariConfig: jdbc4ConnectionTest.............false
2015-10-06 12:26:44,275 DEBUG [localhost-startStop-1] HikariConfig: jdbcUrl.........................
2015-10-06 12:26:44,275 DEBUG [localhost-startStop-1] HikariConfig: leakDetectionThreshold..........0
2015-10-06 12:26:44,275 DEBUG [localhost-startStop-1] HikariConfig: maxLifetime.....................1800000
2015-10-06 12:26:44,275 DEBUG [localhost-startStop-1] HikariConfig: maximumPoolSize.................20
2015-10-06 12:26:44,275 DEBUG [localhost-startStop-1] HikariConfig: metricRegistry..................com.codahale.metrics.MetricRegistry@63d2fc48
2015-10-06 12:26:44,275 DEBUG [localhost-startStop-1] HikariConfig: metricsTrackerFactory...........
2015-10-06 12:26:44,275 DEBUG [localhost-startStop-1] HikariConfig: minimumIdle.....................10
2015-10-06 12:26:44,275 DEBUG [localhost-startStop-1] HikariConfig: password........................<masked>
2015-10-06 12:26:44,275 DEBUG [localhost-startStop-1] HikariConfig: poolName........................HikariPool-0
2015-10-06 12:26:44,275 DEBUG [localhost-startStop-1] HikariConfig: readOnly........................false
2015-10-06 12:26:44,275 DEBUG [localhost-startStop-1] HikariConfig: registerMbeans..................false
2015-10-06 12:26:44,275 DEBUG [localhost-startStop-1] HikariConfig: scheduledExecutorService........
2015-10-06 12:26:44,275 DEBUG [localhost-startStop-1] HikariConfig: threadFactory...................
2015-10-06 12:26:44,275 DEBUG [localhost-startStop-1] HikariConfig: transactionIsolation............
2015-10-06 12:26:44,275 DEBUG [localhost-startStop-1] HikariConfig: username........................
2015-10-06 12:26:44,275 DEBUG [localhost-startStop-1] HikariConfig: validationTimeout...............5000
2015-10-06 12:26:44,276 INFO  [localhost-startStop-1] HikariDataSource: HikariPool-0 - is starting.
2015-10-06 12:26:44,432 DEBUG [localhost-startStop-1] PoolElf: HikariPool-0 - Connection.setNetworkTimeout() is not supported (Method org.postgresql.jdbc4.Jdbc4Connection.getNetworkTimeout() is not yet implemented.)

Full stack trace:

完整的堆栈跟踪：

2015-10-06 12:09:36,885 DEBUG [http-nio-8080-exec-25] PoolElf: HikariPool-0 - Reset (nothing) on connection org.postgresql.jdbc4.Jdbc4Connection@3cc4d919
2015-10-06 12:09:42,651 DEBUG [Hikari housekeeper (pool HikariPool-0)] HikariPool: Before cleanup   pool HikariPool-0 stats (total=20, active=20, idle=0, waiting=1)
2015-10-06 12:09:42,652 DEBUG [Hikari housekeeper (pool HikariPool-0)] HikariPool: After cleanup    pool HikariPool-0 stats (total=20, active=20, idle=0, waiting=1)
2015-10-06 12:10:06,885 DEBUG [http-nio-8080-exec-25] HikariPool: Timeout failure   pool HikariPool-0 stats (total=20, active=20, idle=0, waiting=0)
2015-10-06 12:10:06,885 WARN  [http-nio-8080-exec-25] SqlExceptionHelper: SQL Error: 0, SQLState: null
2015-10-06 12:10:06,885 ERROR [http-nio-8080-exec-25] SqlExceptionHelper: HikariPool-0 - Connection is not available, request timed out after 30000ms.
2015-10-06 12:10:06,885 DEBUG [http-nio-8080-exec-25] PoolElf: HikariPool-0 - Reset (nothing) on connection org.postgresql.jdbc4.Jdbc4Connection@3cc4d919
2015-10-06 12:10:06,886 ERROR [http-nio-8080-exec-25] ErrorPageFilter: Forwarding to error page from request [/api/courses/121387/quizzes/i6fa2562510bf8578712380a87a433e97/student/30175] due to exception [org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.hibernate.exception.JDBCConnectionException: Could not open connection]
java.lang.RuntimeException: org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.hibernate.exception.JDBCConnectionException: Could not open connection
    at lms.security.xauth.XAuthTokenFilter.doFilter(XAuthTokenFilter.java:86) ~[XAuthTokenFilter.class:na]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330) ~[spring-security-web-4.0.0.RELEASE.jar:na]
    at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:120) ~[spring-security-web-4.0.0.RELEASE.jar:na]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330) ~[spring-security-web-4.0.0.RELEASE.jar:na]
    at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:64) ~[spring-security-web-4.0.0.RELEASE.jar:na]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330) ~[spring-security-web-4.0.0.RELEASE.jar:na]
    at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:91) ~[spring-security-web-4.0.0.RELEASE.jar:na]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330) ~[spring-security-web-4.0.0.RELEASE.jar:na]
    at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:53) ~[spring-security-web-4.0.0.RELEASE.jar:na]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330) ~[spring-security-web-4.0.0.RELEASE.jar:na]
    at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:213) ~[spring-security-web-4.0.0.RELEASE.jar:na]
    at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:176) ~[spring-security-web-4.0.0.RELEASE.jar:na]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239) [catalina.jar:8.0.23]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) [catalina.jar:8.0.23]
    at org.springframework.boot.actuate.trace.WebRequestTraceFilter.doFilterInternal(WebRequestTraceFilter.java:102) ~[spring-boot-actuator-1.2.3.RELEASE.jar:1.2.3.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239) [catalina.jar:8.0.23]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) [catalina.jar:8.0.23]
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:85) ~[spring-web-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239) [catalina.jar:8.0.23]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) [catalina.jar:8.0.23]
    at org.springframework.boot.context.web.ErrorPageFilter.doFilter(ErrorPageFilter.java:113) [spring-boot-1.2.3.RELEASE.jar:1.2.3.RELEASE]
    at org.springframework.boot.context.web.ErrorPageFilter.access##代码##0(ErrorPageFilter.java:59) [spring-boot-1.2.3.RELEASE.jar:1.2.3.RELEASE]
    at org.springframework.boot.context.web.ErrorPageFilter.doFilterInternal(ErrorPageFilter.java:88) [spring-boot-1.2.3.RELEASE.jar:1.2.3.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.boot.context.web.ErrorPageFilter.doFilter(ErrorPageFilter.java:106) [spring-boot-1.2.3.RELEASE.jar:1.2.3.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239) [catalina.jar:8.0.23]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) [catalina.jar:8.0.23]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219) [catalina.jar:8.0.23]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106) [catalina.jar:8.0.23]
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502) [catalina.jar:8.0.23]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142) [catalina.jar:8.0.23]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79) [catalina.jar:8.0.23]
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:617) [catalina.jar:8.0.23]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88) [catalina.jar:8.0.23]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518) [catalina.jar:8.0.23]
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091) [tomcat-coyote.jar:8.0.23]
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:668) [tomcat-coyote.jar:8.0.23]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1521) [tomcat-coyote.jar:8.0.23]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1478) [tomcat-coyote.jar:8.0.23]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_45]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_45]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-util.jar:8.0.23]
    at java.lang.Thread.run(Thread.java:745) [na:1.8.0_45]
Caused by: org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.hibernate.exception.JDBCConnectionException: Could not open connection
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:978) ~[spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:868) ~[spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:648) ~[servlet-api.jar:na]
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842) ~[spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) ~[servlet-api.jar:na]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291) [catalina.jar:8.0.23]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) [catalina.jar:8.0.23]
    at com.codahale.metrics.servlet.AbstractInstrumentedFilter.doFilter(AbstractInstrumentedFilter.java:104) ~[metrics-servlet-3.1.1.jar:3.1.1]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239) [catalina.jar:8.0.23]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) [catalina.jar:8.0.23]
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) ~[tomcat-websocket.jar:8.0.23]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239) [catalina.jar:8.0.23]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) [catalina.jar:8.0.23]
    at org.springframework.boot.actuate.autoconfigure.EndpointWebMvcAutoConfiguration$ApplicationContextHeaderFilter.doFilterInternal(EndpointWebMvcAutoConfiguration.java:291) ~[spring-boot-actuator-1.2.3.RELEASE.jar:1.2.3.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239) [catalina.jar:8.0.23]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) [catalina.jar:8.0.23]
    at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:77) ~[spring-web-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239) [catalina.jar:8.0.23]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) [catalina.jar:8.0.23]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:316) ~[spring-security-web-4.0.0.RELEASE.jar:na]
    at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:126) ~[spring-security-web-4.0.0.RELEASE.jar:na]
    at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:90) ~[spring-security-web-4.0.0.RELEASE.jar:na]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330) ~[spring-security-web-4.0.0.RELEASE.jar:na]
    at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:114) ~[spring-security-web-4.0.0.RELEASE.jar:na]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330) ~[spring-security-web-4.0.0.RELEASE.jar:na]
    at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:122) ~[spring-security-web-4.0.0.RELEASE.jar:na]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330) ~[spring-security-web-4.0.0.RELEASE.jar:na]
    at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:111) ~[spring-security-web-4.0.0.RELEASE.jar:na]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330) ~[spring-security-web-4.0.0.RELEASE.jar:na]
    at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:168) ~[spring-security-web-4.0.0.RELEASE.jar:na]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330) ~[spring-security-web-4.0.0.RELEASE.jar:na]
    at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:48) ~[spring-security-web-4.0.0.RELEASE.jar:na]
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330) ~[spring-security-web-4.0.0.RELEASE.jar:na]
    at lms.security.xauth.XAuthTokenFilter.doFilter(XAuthTokenFilter.java:84) ~[XAuthTokenFilter.class:na]
    ... 46 common frames omitted
Caused by: org.hibernate.exception.JDBCConnectionException: Could not open connection
    at org.hibernate.exception.internal.SQLExceptionTypeDelegate.convert(SQLExceptionTypeDelegate.java:65) ~[hibernate-core-4.3.6.Final.jar:4.3.6.Final]
    at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:49) ~[hibernate-core-4.3.6.Final.jar:4.3.6.Final]
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:126) ~[hibernate-core-4.3.6.Final.jar:4.3.6.Final]
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:112) ~[hibernate-core-4.3.6.Final.jar:4.3.6.Final]
    at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.obtainConnection(LogicalConnectionImpl.java:235) ~[hibernate-core-4.3.6.Final.jar:4.3.6.Final]
    at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.getConnection(LogicalConnectionImpl.java:171) ~[hibernate-core-4.3.6.Final.jar:4.3.6.Final]
    at org.hibernate.engine.transaction.internal.jdbc.JdbcTransaction.doBegin(JdbcTransaction.java:67) ~[hibernate-core-4.3.6.Final.jar:4.3.6.Final]
    at org.hibernate.engine.transaction.spi.AbstractTransactionImpl.begin(AbstractTransactionImpl.java:162) ~[hibernate-core-4.3.6.Final.jar:4.3.6.Final]
    at org.hibernate.internal.SessionImpl.beginTransaction(SessionImpl.java:1435) ~[hibernate-core-4.3.6.Final.jar:4.3.6.Final]
    at org.hibernate.collection.internal.AbstractPersistentCollection.withTemporarySessionIfNeeded(AbstractPersistentCollection.java:250) ~[hibernate-core-4.3.6.Final.jar:4.3.6.Final]
    at org.hibernate.collection.internal.AbstractPersistentCollection.readElementByIndex(AbstractPersistentCollection.java:376) ~[hibernate-core-4.3.6.Final.jar:4.3.6.Final]
    at org.hibernate.collection.internal.PersistentMap.get(PersistentMap.java:164) ~[hibernate-core-4.3.6.Final.jar:4.3.6.Final]
    at java_util_Map$get.call(Unknown Source) ~[na:na]
    at lms.service.QuizService.processAnswers(QuizService.groovy:66) ~[QuizService.class:na]
    at lms.service.QuizService$$FastClassBySpringCGLIB$dcc8beb.invoke(<generated>) ~[spring-core-4.1.6.RELEASE.jar:na]
    at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204) ~[spring-core-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:717) ~[spring-aop-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157) ~[spring-aop-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.transaction.interceptor.TransactionInterceptor.proceedWithInvocation(TransactionInterceptor.java:99) ~[spring-tx-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:281) ~[spring-tx-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96) ~[spring-tx-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:653) ~[spring-aop-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at lms.service.QuizService$$EnhancerBySpringCGLIB$a60c0a.processAnswers(<generated>) ~[spring-core-4.1.6.RELEASE.jar:na]
    at lms.web.rest.CourseResource.saveQuizResults(CourseResource.java:537) ~[CourseResource.class:na]
    at lms.web.rest.CourseResource$$FastClassBySpringCGLIB$$e3d2ba4d.invoke(<generated>) ~[spring-core-4.1.6.RELEASE.jar:na]
    at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204) ~[spring-core-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:717) ~[spring-aop-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157) ~[spring-aop-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.security.access.intercept.aopalliance.MethodSecurityInterceptor.invoke(MethodSecurityInterceptor.java:68) ~[spring-security-core-4.0.0.RELEASE.jar:na]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at com.ryantenney.metrics.spring.TimedMethodInterceptor.invoke(TimedMethodInterceptor.java:48) ~[metrics-spring-3.0.4.jar:na]
    at com.ryantenney.metrics.spring.TimedMethodInterceptor.invoke(TimedMethodInterceptor.java:34) ~[metrics-spring-3.0.4.jar:na]
    at com.ryantenney.metrics.spring.AbstractMetricMethodInterceptor.invoke(AbstractMetricMethodInterceptor.java:59) ~[metrics-spring-3.0.4.jar:na]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:653) ~[spring-aop-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at lms.web.rest.CourseResource$$EnhancerBySpringCGLIB$$ff854301.saveQuizResults(<generated>) ~[spring-core-4.1.6.RELEASE.jar:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_45]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_45]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_45]
    at java.lang.reflect.Method.invoke(Method.java:497) ~[na:1.8.0_45]
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:221) ~[spring-web-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:137) ~[spring-web-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110) ~[spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:776) ~[spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:705) ~[spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) ~[spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959) ~[spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893) ~[spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966) ~[spring-webmvc-4.1.6.RELEASE.jar:4.1.6.RELEASE]
    ... 81 common frames omitted
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:213) ~[HikariCP-2.4.1.jar:na]
    at com.zaxxer.hikari.pool.HikariPool.getConnection(HikariPool.java:163) ~[HikariCP-2.4.1.jar:na]
    at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:85) ~[HikariCP-2.4.1.jar:na]
    at org.hibernate.engine.jdbc.connections.internal.DatasourceConnectionProviderImpl.getConnection(DatasourceConnectionProviderImpl.java:139) ~[hibernate-core-4.3.6.Final.jar:4.3.6.Final]
    at org.hibernate.internal.AbstractSessionImpl$NonContextualJdbcConnectionAccess.obtainConnection(AbstractSessionImpl.java:380) ~[hibernate-core-4.3.6.Final.jar:4.3.6.Final]
    at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.obtainConnection(LogicalConnectionImpl.java:228) ~[hibernate-core-4.3.6.Final.jar:4.3.6.Final]
    ... 126 common frames omitted
2015-10-06 12:10:12,651 DEBUG [Hikari housekeeper (pool HikariPool-0)] HikariPool: Before cleanup   pool HikariPool-0 stats (total=20, active=19, idle=1, waiting=0)
2015-10-06 12:10:12,652 DEBUG [Hikari housekeeper (pool HikariPool-0)] HikariPool: After cleanup    pool HikariPool-0 stats (total=20, active=19, idle=1, waiting=0)

Any clue would be helpful!

任何线索都会有所帮助！

采纳答案by dfche

I managed to fix it finally. The problem is not related to HikariCP. The problem persisted because of some complex methods in REST controllers executing multiple changes in DB through JPA repositories. For some reasons calls to these interfaces resulted in a growing number of "freezed" active connections, exhausting the pool. Either annotating these methods as @Transactionalor enveloping all the logic in a single call to transactional service method seem to solve the problem.

我终于设法修复了它。该问题与 HikariCP 无关。由于 REST 控制器中的一些复杂方法通过 JPA 存储库在 DB 中执行多个更改，因此问题仍然存在。由于某些原因，对这些接口的调用导致了越来越多的“冻结”活动连接，耗尽了池。将这些方法注释为@Transactional或将所有逻辑包含在对事务服务方法的单个调用中似乎可以解决问题。

回答by Nitin

From stack trace:

从堆栈跟踪：

HikariPool: Timeout failure pool HikariPool-0 stats (total=20, active=20, idle=0, waiting=0) Means pool reached maximum connections limit set in configuration.

HikariPool：超时故障池 HikariPool-0 stats (total=20, active=20, idle=0, waiting=0) 表示池达到配置中设置的最大连接限制。

The next line: HikariPool-0 - Connection is not available, request timed out after 30000ms. Means pool waited 30000ms for free connection but your application not returned any connection meanwhile.

下一行：HikariPool-0 - 连接不可用，请求在 30000 毫秒后超时。意味着池等待了 30000 毫秒以获得免费连接，但您的应用程序同时没有返回任何连接。

Mostly it is connection leak (connection is not closed after borrowing from pool), set leakDetectionThreshold to the maximum value that you expect SQL query would take to execute.

主要是连接泄漏（从池中借用后连接未关闭），将leakDetectionThreshold 设置为您期望执行SQL 查询所需的最大值。

otherwise, your maximum connections 'at a time' requirement is higher than 20 !

否则，您“一次”的最大连接数要求高于 20 ！