After using sonatype nexus 3 for a few hours, I see error, "Unable to acquire connection from main pool, trying overflow"

Hi,

After using sonatype nexus 3 for a few hours, I see the following error:

2019-11-01 00:16:00,088-0500 DEBUG [qtp2130725876-2531] admin org.sonatype.nexus.orient.DatabasePoolWithOverflowImpl - Unable to acquire connection from main pool, trying overflow
java.lang.IllegalStateException: You have reached maximum pool size for given partition
at com.orientechnologies.orient.core.db.OPartitionedDatabasePool.acquire(OPartitionedDatabasePool.java:244)
at org.sonatype.nexus.orient.DatabasePoolWithOverflowImpl.acquire(DatabasePoolWithOverflowImpl.java:64)
at org.sonatype.nexus.orient.DatabaseInstanceImpl.acquire(DatabaseInstanceImpl.java:70)
at org.sonatype.nexus.repository.storage.StorageFacetImpl.lambda$0(StorageFacetImpl.java:156)
at org.sonatype.nexus.repository.browse.internal.BrowseServiceImpl.browseComponentAssets(BrowseServiceImpl.java:164)
at org.sonatype.nexus.repository.rest.internal.resources.SearchResource.toComponent(SearchResource.java:146)
at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193)
at java.util.Spliterators$ArraySpliterator.forEachRemaining(Spliterators.java:948)
at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:481)
at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471)
at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:708)
at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:499)
at org.sonatype.nexus.repository.rest.internal.resources.SearchResource.search(SearchResource.java:133)
at sun.reflect.GeneratedMethodAccessor143.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.jboss.resteasy.core.MethodInjectorImpl.invoke(MethodInjectorImpl.java:140)
at org.jboss.resteasy.core.ResourceMethodInvoker.invokeOnTarget(ResourceMethodInvoker.java:294)
at org.jboss.resteasy.core.ResourceMethodInvoker.invoke(ResourceMethodInvoker.java:248)
at org.jboss.resteasy.core.ResourceMethodInvoker.invoke(ResourceMethodInvoker.java:235)
at org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:402)
at org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:209)
at org.jboss.resteasy.plugins.server.servlet.ServletContainerDispatcher.service(ServletContainerDispatcher.java:227)
at org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:56)
at org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:51)
at org.sonatype.nexus.siesta.internal.resteasy.ComponentContainerImpl.service(ComponentContainerImpl.java:106)
at org.sonatype.nexus.siesta.SiestaServlet.service(SiestaServlet.java:137)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
at com.google.inject.servlet.ServletDefinition.doServiceImpl(ServletDefinition.java:286)
at com.google.inject.servlet.ServletDefinition.doService(ServletDefinition.java:276)
at com.google.inject.servlet.ServletDefinition.service(ServletDefinition.java:181)
at com.google.inject.servlet.DynamicServletPipeline.service(DynamicServletPipeline.java:71)
at com.google.inject.servlet.FilterChainInvocation.doFilter(FilterChainInvocation.java:85)
at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:112)
at com.google.inject.servlet.FilterChainInvocation.doFilter(FilterChainInvocation.java:82)
at org.apache.shiro.web.servlet.ProxiedFilterChain.doFilter(ProxiedFilterChain.java:61)
at org.apache.shiro.web.servlet.AdviceFilter.executeChain(AdviceFilter.java:108)
at org.apache.shiro.web.servlet.AdviceFilter.doFilterInternal(AdviceFilter.java:137)
at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125)
at org.apache.shiro.web.servlet.ProxiedFilterChain.doFilter(ProxiedFilterChain.java:66)
at org.apache.shiro.web.servlet.AdviceFilter.executeChain(AdviceFilter.java:108)
at org.apache.shiro.web.servlet.AdviceFilter.doFilterInternal(AdviceFilter.java:137)
at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125)
at org.apache.shiro.web.servlet.ProxiedFilterChain.doFilter(ProxiedFilterChain.java:66)
at org.apache.shiro.web.servlet.AdviceFilter.executeChain(AdviceFilter.java:108)
at org.apache.shiro.web.servlet.AdviceFilter.doFilterInternal(AdviceFilter.java:137)
at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125)
at org.apache.shiro.web.servlet.ProxiedFilterChain.doFilter(ProxiedFilterChain.java:66)
at org.apache.shiro.web.servlet.AbstractShiroFilter.executeChain(AbstractShiroFilter.java:449)
at org.sonatype.nexus.security.SecurityFilter.executeChain(SecurityFilter.java:85)
at org.apache.shiro.web.servlet.AbstractShiroFilter$1.call(AbstractShiroFilter.java:365)
at org.apache.shiro.subject.support.SubjectCallable.doCall(SubjectCallable.java:90)
at org.apache.shiro.subject.support.SubjectCallable.call(SubjectCallable.java:83)
at org.apache.shiro.subject.support.DelegatingSubject.execute(DelegatingSubject.java:383)
at org.apache.shiro.web.servlet.AbstractShiroFilter.doFilterInternal(AbstractShiroFilter.java:362)
at org.sonatype.nexus.security.SecurityFilter.doFilterInternal(SecurityFilter.java:101)
at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125)
at com.google.inject.servlet.FilterChainInvocation.doFilter(FilterChainInvocation.java:82)
at com.sonatype.nexus.licensing.internal.LicensingRedirectFilter.doFilter(LicensingRedirectFilter.java:108)
at com.google.inject.servlet.FilterChainInvocation.doFilter(FilterChainInvocation.java:82)
at com.codahale.metrics.servlet.AbstractInstrumentedFilter.doFilter(AbstractInstrumentedFilter.java:97)
at com.google.inject.servlet.FilterChainInvocation.doFilter(FilterChainInvocation.java:82)
at org.sonatype.nexus.internal.web.ErrorPageFilter.doFilter(ErrorPageFilter.java:68)
at com.google.inject.servlet.FilterChainInvocation.doFilter(FilterChainInvocation.java:82)
at org.sonatype.nexus.internal.web.EnvironmentFilter.doFilter(EnvironmentFilter.java:101)
at com.google.inject.servlet.FilterChainInvocation.doFilter(FilterChainInvocation.java:82)
at org.sonatype.nexus.internal.web.HeaderPatternFilter.doFilter(HeaderPatternFilter.java:98)
at com.google.inject.servlet.FilterChainInvocation.doFilter(FilterChainInvocation.java:82)
at com.google.inject.servlet.DynamicFilterPipeline.dispatch(DynamicFilterPipeline.java:104)
at com.google.inject.servlet.GuiceFilter.doFilter(GuiceFilter.java:135)
at org.sonatype.nexus.bootstrap.osgi.DelegatingFilter.doFilter(DelegatingFilter.java:73)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1634)
at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:533)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:146)
at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:548)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:257)
at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1595)
at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:255)
at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1317)
at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:203)
at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:473)
at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1564)
at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:201)
at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1219)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:144)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
at com.codahale.metrics.jetty9.InstrumentedHandler.handle(InstrumentedHandler.java:175)
at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:126)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
at org.eclipse.jetty.server.Server.handle(Server.java:531)
at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:352)
at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:260)
at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:281)
at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:102)
at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:118)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:333)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:310)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:168)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:126)
at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:366)
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:762)
at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:680)
at java.lang.Thread.run(Thread.java:745)

How can we fix this error ?

Thanks,
Karthick

Do you have any custom groovy scripts? If so, make sure you are closing transactions: