Server error when requesting pages concurrently

Cause

org.springframework.orm.hibernate.HibernateSystemException: SQL
insert, update or delete failed (row not found); nested exception is
net.sf.hibernate.HibernateException: SQL insert, update or delete
failed (row not found)
   at org.springframework.orm.hibernate.SessionFactoryUtils.convertHibernateAccessException(SessionFactoryUtils.java:597)

caused by: net.sf.hibernate.HibernateException: SQL insert, update or
delete failed (row not found)
   at net.sf.hibernate.impl.NonBatchingBatcher.addToBatch(NonBatchingBatcher.java:25)
Stack Trace:[hide]

org.springframework.orm.hibernate.HibernateSystemException: SQL
insert, update or delete failed (row not found); nested exception is
net.sf.hibernate.HibernateException: SQL insert, update or delete
failed (row not found)
Caused by: net.sf.hibernate.HibernateException: SQL insert, update or
delete failed (row not found)
       at net.sf.hibernate.impl.NonBatchingBatcher.addToBatch(NonBatchingBatcher.java:25)
       at net.sf.hibernate.persister.EntityPersister.delete(EntityPersister.java:581)
       at net.sf.hibernate.impl.ScheduledDeletion.execute(ScheduledDeletion.java:29)
       at net.sf.hibernate.impl.SessionImpl.execute(SessionImpl.java:2447)
       at net.sf.hibernate.impl.SessionImpl.executeAll(SessionImpl.java:2433)
       at net.sf.hibernate.impl.SessionImpl.execute(SessionImpl.java:2395)
       at net.sf.hibernate.impl.SessionImpl.flush(SessionImpl.java:2259)
       at net.sf.hibernate.impl.SessionImpl.forceFlush(SessionImpl.java:767)
       at net.sf.hibernate.impl.SessionImpl.doSave(SessionImpl.java:847)
       at net.sf.hibernate.impl.SessionImpl.saveWithGeneratedIdentifier(SessionImpl.java:788)
       at net.sf.hibernate.impl.SessionImpl.save(SessionImpl.java:747)
       at org.springframework.orm.hibernate.HibernateTemplate$9.doInHibernate(HibernateTemplate.java:568)
       at org.springframework.orm.hibernate.HibernateTemplate.execute(HibernateTemplate.java:370)
       at org.springframework.orm.hibernate.HibernateTemplate.save(HibernateTemplate.java:565)
       at bucket.user.persistence.dao.hibernate.BucketPropertySetDAO.setImpl(BucketPropertySetDAO.java:39)
       at sun.reflect.GeneratedMethodAccessor598.invoke(Unknown Source)
       at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
       at java.lang.reflect.Method.invoke(Method.java:597)
       at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:304)
       at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:182)
       at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:149)
       at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:106)
       at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
       at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
       at $Proxy61.setImpl(Unknown Source)
       at bucket.user.propertyset.BucketPropertySet.setImpl(BucketPropertySet.java:163)
       at com.opensymphony.module.propertyset.AbstractPropertySet.set(AbstractPropertySet.java:570)
       at com.opensymphony.module.propertyset.AbstractPropertySet.setDate(AbstractPropertySet.java:253)
       at com.atlassian.user.impl.cache.properties.CachedPropertySet.setDate(CachedPropertySet.java:210)
       at com.atlassian.user.impl.cache.properties.CachingPropertySetFactory$RecacheOnWritePropertySet.setDate(CachingPropertySetFactory.java:126)
       at com.atlassian.confluence.security.login.DefaultLoginManager.onSuccessfulLoginAttempt(DefaultLoginManager.java:209)
       at sun.reflect.GeneratedMethodAccessor802.invoke(Unknown Source)
       at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
       at java.lang.reflect.Method.invoke(Method.java:597)
       at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:304)
       at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:182)
       at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:149)
       at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:106)
       at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
       at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
       at $Proxy80.onSuccessfulLoginAttempt(Unknown Source)
       at com.atlassian.confluence.security.seraph.ConfluenceElevatedSecurityGuard.onSuccessfulLoginAttempt(ConfluenceElevatedSecurityGuard.java:97)
       at com.atlassian.seraph.auth.DefaultAuthenticator.getUserFromCookie(DefaultAuthenticator.java:454)
       at com.atlassian.seraph.auth.DefaultAuthenticator.getUser(DefaultAuthenticator.java:334)
       at com.atlassian.confluence.user.ConfluenceAuthenticator.getUser(ConfluenceAuthenticator.java:79)
       at com.atlassian.seraph.filter.SecurityFilter.doFilter(SecurityFilter.java:129)
       at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
       at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
       at com.atlassian.security.auth.trustedapps.filter.TrustedApplicationsFilter.doFilter(TrustedApplicationsFilter.java:98)
       at com.atlassian.confluence.util.AbstractBootstrapHotSwappingFilter.doFilter(AbstractBootstrapHotSwappingFilter.java:30)
       at com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)
       at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
       at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
       at com.atlassian.seraph.filter.BaseLoginFilter.doFilter(BaseLoginFilter.java:140)
       at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
       at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
       at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:46)
       at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter$1.doFilter(DelegatingPluginFilter.java:66)
       at com.atlassian.oauth.serviceprovider.internal.servlet.OAuthFilter.doFilter(OAuthFilter.java:69)
       at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter.doFilter(DelegatingPluginFilter.java:74)
       at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:42)
       at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:77)
       at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:63)
       at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
       at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
       at com.atlassian.confluence.util.ClusterHeaderFilter.doFilter(ClusterHeaderFilter.java:34)
       at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
       at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
       at com.atlassian.johnson.filters.AbstractJohnsonFilter.doFilter(AbstractJohnsonFilter.java:72)
       at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
       at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
       at org.springframework.orm.hibernate.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:170)
       at com.atlassian.spring.filter.FlushingSpringSessionInViewFilter.doFilterInternal(FlushingSpringSessionInViewFilter.java:29)
       at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:75)
       at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
       at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
       at com.atlassian.confluence.util.ConfluenceErrorFilter.doFilter(ConfluenceErrorFilter.java:22)
       at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
       at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
       at com.atlassian.util.profiling.filters.ProfilingFilter.doFilter(ProfilingFilter.java:99)
       at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
       at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
       at com.atlassian.confluence.core.datetime.RequestTimeThreadLocalFilter.doFilter(RequestTimeThreadLocalFilter.java:35)
       at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
       at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
       at com.atlassian.confluence.util.RequestCacheThreadLocalFilter.doFilter(RequestCacheThreadLocalFilter.java:25)
       at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
       at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
       at com.atlassian.gzipfilter.GzipFilter.doFilterInternal(GzipFilter.java:81)
       at com.atlassian.gzipfilter.GzipFilter.doFilter(GzipFilter.java:51)
       at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
       at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
       at com.atlassian.core.filters.cache.AbstractCachingFilter.doFilter(AbstractCachingFilter.java:33)
       at com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)
       at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
       at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
       at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:46)
       at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter$1.doFilter(DelegatingPluginFilter.java:66)
       at com.atlassian.confluence.extra.webdav.servlet.filter.ReverseProxyFilter.doFilter(ReverseProxyFilter.java:427)
       at com.atlassian.confluence.extra.webdav.servlet.filter.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:34)
       at com.atlassian.plugin.servlet.filter.DelegatingPluginFilter.doFilter(DelegatingPluginFilter.java:74)
       at com.atlassian.plugin.servlet.filter.IteratingFilterChain.doFilter(IteratingFilterChain.java:42)
       at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:77)
       at com.atlassian.plugin.servlet.filter.ServletFilterModuleContainerFilter.doFilter(ServletFilterModuleContainerFilter.java:63)
       at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
       at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
       at com.atlassian.confluence.web.filter.validateparam.RequestParamValidationFilter.doFilter(RequestParamValidationFilter.java:58)
       at com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)
       at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
       at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
       at com.atlassian.confluence.plugin.servlet.filter.ActionContextCleanUp.doFilter(ActionContextCleanUp.java:71)
       at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
       at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
       at com.atlassian.core.filters.encoding.AbstractEncodingFilter.doFilter(AbstractEncodingFilter.java:41)
       at com.atlassian.core.filters.AbstractHttpFilter.doFilter(AbstractHttpFilter.java:31)
       at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
       at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
       at com.atlassian.core.filters.HeaderSanitisingFilter.doFilter(HeaderSanitisingFilter.java:44)
       at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
       at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
       at com.atlassian.confluence.servlet.FourOhFourErrorLoggingFilter.doFilter(FourOhFourErrorLoggingFilter.java:65)
       at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
       at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
       at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
       at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
       at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
       at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
       at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
       at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
       at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:852)
       at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
       at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
       at java.lang.Thread.run(Thread.java:619)