title: Apparent connection leak detected with Hikari CP
body: <p>When using native sql operator <strong>IN</strong> i get exception. Although it throws an exception, it still works as it was intended, but the exception in the logs is a bit annoying. I think it has something to do with the <strong>IN</strong> operator.</p>
  
  <pre><code>@Query("select c from Contact c where c.id in :ids")
  List&lt;Contact&gt; findByContactsIds(@Param("ids") List&lt;Integer&gt; contactsIds);
  </code></pre>
  
  <p>config:</p>
  
  <pre><code>spring.datasource.hikari.max-lifetime=900000
  spring.datasource.hikari.leakDetectionThreshold=2000
  spring.datasource.hikari.idle-timeout=900000
  </code></pre>
  
  <p>exception:</p>
  
  <pre><code>2019-02-26 11:25:16.252  WARN 924 --- [l-1 housekeeper] com.zaxxer.hikari.pool.ProxyLeakTask     : Connection leak detection triggered for com.mysql.jdbc.JDBC4Connection@ffd3737 on thread http-nio-80-exec-8, stack trace follows
  
  java.lang.Exception: Apparent connection leak detected
      at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:128) ~[HikariCP-2.7.9.jar:na]
      at org.hibernate.engine.jdbc.connections.internal.DatasourceConnectionProviderImpl.getConnection(DatasourceConnectionProviderImpl.java:122) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
      at org.hibernate.internal.NonContextualJdbcConnectionAccess.obtainConnection(NonContextualJdbcConnectionAccess.java:35) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
      at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.acquireConnectionIfNeeded(LogicalConnectionManagedImpl.java:106) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
      at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.getPhysicalConnection(LogicalConnectionManagedImpl.java:136) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
      at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.getConnectionForTransactionManagement(LogicalConnectionManagedImpl.java:254) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
      at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.begin(LogicalConnectionManagedImpl.java:262) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
      at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl$TransactionDriverControlImpl.begin(JdbcResourceLocalTransactionCoordinatorImpl.java:214) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
      at org.hibernate.engine.transaction.internal.TransactionImpl.begin(TransactionImpl.java:56) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
      at org.springframework.orm.jpa.vendor.HibernateJpaDialect.beginTransaction(HibernateJpaDialect.java:162) ~[spring-orm-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at org.springframework.orm.jpa.JpaTransactionManager.doBegin(JpaTransactionManager.java:400) ~[spring-orm-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at org.springframework.transaction.support.AbstractPlatformTransactionManager.getTransaction(AbstractPlatformTransactionManager.java:378) ~[spring-tx-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at org.springframework.transaction.interceptor.TransactionAspectSupport.createTransactionIfNecessary(TransactionAspectSupport.java:474) ~[spring-tx-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:289) ~[spring-tx-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:98) ~[spring-tx-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:139) ~[spring-tx-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:135) ~[spring-data-jpa-2.0.10.RELEASE.jar:2.0.10.RELEASE]
      at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92) ~[spring-aop-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at org.springframework.data.repository.core.support.SurroundingTransactionDetectorMethodInterceptor.invoke(SurroundingTransactionDetectorMethodInterceptor.java:61) ~[spring-data-commons-2.0.10.RELEASE.jar:2.0.10.RELEASE]
      at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212) ~[spring-aop-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at com.sun.proxy.$Proxy134.findByContactsIds(Unknown Source) ~[na:na]
      at enera.handbook.controller.PassesController.generatePassesPdf(PassesController.java:71) ~[classes/:na]
      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_144]
      at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_144]
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_144]
      at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_144]
      at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:209) ~[spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136) ~[spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:891) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:797) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:974) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:877) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at javax.servlet.http.HttpServlet.service(HttpServlet.java:661) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
      at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:851) ~[spring-webmvc-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
      at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) ~[tomcat-embed-websocket-8.5.34.jar:8.5.34]
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:320) ~[spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
      at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:127) ~[spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
      at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:91) ~[spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
      at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:119) ~[spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
      at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:137) ~[spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
      at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:111) ~[spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
      at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:170) ~[spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
      at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:63) ~[spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
      at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:200) ~[spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
      at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:116) ~[spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
      at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:66) ~[spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
      at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
      at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:105) ~[spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
      at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:56) ~[spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
      at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) ~[spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
      at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:215) ~[spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
      at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:178) ~[spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
      at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:357) ~[spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:270) ~[spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
      at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
      at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:109) ~[spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
      at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93) ~[spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
      at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200) ~[spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
      at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
      at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
      at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:493) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
      at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
      at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
      at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
      at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
      at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:800) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
      at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
      at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:806) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
      at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1498) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
      at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
      at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) ~[na:1.8.0_144]
      at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) ~[na:1.8.0_144]
      at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-8.5.34.jar:8.5.34]
      at java.lang.Thread.run(Thread.java:748) [na:1.8.0_144]
  
  2019-02-26 11:25:34.741 DEBUG 924 --- [l-1 housekeeper] com.zaxxer.hikari.pool.HikariPool        : HikariPool-1 - Pool stats (total=10, active=1, idle=9, waiting=0)
  2019-02-26 11:25:35.024  INFO 924 --- [p-nio-80-exec-8] com.zaxxer.hikari.pool.ProxyLeakTask     : Previously reported leaked connection com.mysql.jdbc.JDBC4Connection@ffd3737 on thread http-nio-80-exec-8 was returned to the pool (unleaked)
  </code></pre>
  
  <p>Why do I have to think all the time what to write so that the validator misses me</p>