RedGate Monitor Blocking Processes Overview

FTP2It

Hi,
In the Blocking Processes section in the Overview, I'm getting this error message for the "Blocking processes (top 10 by time)" and "SQL user processes (top 10 by CPU)" sections...I checked the event log on the Windows server where the Base Monitor is installed and found this repeated error message...I'm currently using version 14.0.43.6273. Thanks.

2025-01-27 21:27:05,905 [   30] ERROR RedGate.Monitor.UI.Website.Middlewares.CustomErrorHandlingMiddleware - Responding to unhandled exception with JSend error

System.NullReferenceException: Object reference not set to an instance of an object.

   at RedGate.Monitor.Common.Collections.BinaryExtensions.ToHexString(Binary binary, String prefix)

   at RedGate.Monitor.UI.Website.Dtos.Web.SharedOverview.BlockingProcessModel..ctor(ISqlInstance_SqlProcess process, DateTime collectionTime, String fullCommand, ChannelInstanceRef sqlServerCir, IJobRepository jobRepository)

   at RedGate.Monitor.UI.Website.Models.Overview.SqlInstanceOverview.BlockingTreesConstructor.ConstructBlockingModelTreeFromNode(BlockingTreeNode node, DateTime collectionTime, IDictionary`2 handlesToTextStream, ChannelInstanceRef sqlServerCir)

   at RedGate.Monitor.UI.Website.Models.Overview.SqlInstanceOverview.BlockingTreesConstructor.<>c__DisplayClass9_0.<ConstructBlockingModelTrees>b__0(BlockingTreeHeadNode headNode)

   at System.Linq.Enumerable.SelectListIterator`2.Fill(ReadOnlySpan`1 source, Span`1 destination, Func`2 func)

   at System.Linq.Enumerable.SelectListIterator`2.ToList()

   at RedGate.Monitor.UI.Website.ViewModelBuilders.SqlProcessesViewModelBuilder.CreateSqlProcessesViewModel(IReadOnlyCollection`1 sqlProcesses, Func`2 getTextStream, ChannelInstanceRef sqlServerCir, DateTime minDate, DateTime maxDate)

   at RedGate.Monitor.UI.Website.ViewModelBuilders.SqlProcessesViewModelBuilder.CreateViewModel(ChannelInstanceRef`1 dbmsCir, DateTime minDate, DateTime maxDate)

   at RedGate.Monitor.UI.Website.Controllers.SqlProcessesController.Index(ChannelInstanceRef`1 dbmsCir, Int64 startTime, Int64 endTime)

   at lambda_method1948(Closure, Object, Object[])

   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeActionMethodAsync>g__Logged|12_1(ControllerActionInvoker invoker)

   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeNextActionFilterAsync>g__Awaited|10_0(ControllerActionInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)

   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Rethrow(ActionExecutedContextSealed context)

   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)

   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeInnerFilterAsync()

--- End of stack trace from previous location ---

   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeNextExceptionFilterAsync>g__Awaited|26_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)

   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ExceptionContextSealed context)

   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)

   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.InvokeNextResourceFilter()

--- End of stack trace from previous location ---

   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ResourceExecutedContextSealed context)

   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)

   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.InvokeFilterPipelineAsync()

--- End of stack trace from previous location ---

   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Logged|17_1(ResourceInvoker invoker)

   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Logged|17_1(ResourceInvoker invoker)

   at Microsoft.AspNetCore.Session.SessionMiddleware.Invoke(HttpContext context)

   at Microsoft.AspNetCore.Session.SessionMiddleware.Invoke(HttpContext context)

   at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)

   at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)

   at RedGate.Monitor.UI.Website.Authentication.AuthenticationSchemeInitializationMiddleware.Invoke(HttpContext context)

   at RedGate.Monitor.UI.Website.Middlewares.BaseMonitorSetUpMiddleware.Invoke(HttpContext context)

   at RedGate.Monitor.UI.Website.Middlewares.RequestPerformanceLoggingMiddleware.Invoke(HttpContext context)

   at RedGate.Monitor.UI.Website.Middlewares.ApplicationInsightsRequestLoggingMiddleware.Invoke(HttpContext context)

   at StackExchange.Profiling.MiniProfilerMiddleware.Invoke(HttpContext context) in C:\projects\dotnet\src\MiniProfiler.AspNetCore\MiniProfilerMiddleware.cs:line 112

   at RedGate.Monitor.UI.Website.Middlewares.MiniProfilerAddNonceToScriptsMiddleware.Invoke(HttpContext context)

   at RedGate.Monitor.UI.Website.Middlewares.CustomErrorHandlingMiddleware.Invoke(HttpContext context)

FTP2It

This issue I reported has resolved itself somehow.

cperez

Good Morning @FTP2It,

Thanks for reaching out to Redgate Support. Glad that the issue is now resolved on your end. That "System.NullReferenceException: Object reference not set to an instance of an object." historically has a number of different causes, so we would ideally need a copy of your Monitor Logs to see if any other errors are present.

If you see the issue pick back up in the future, I would recommend collecting said logs and then attaching them here and we can see if we can determine if there is a root cause here of if this was just an intirmittant behavior.

DonFerguson

I'm getting that too on 14.0.44.  I made another post before noticing this one.

I was able to reproduce the error on Red-Gate online demo as well.  I observed that sometimes it occurs when setting a larger timeline range.  Like 5 hours or so.

Redgate, please pull the logs from your own online demo.  You should be able to reproduce it by clicking the link below:

https://monitor.red-gate.com/overviews/SQLMON-EC2-BM2/dbms/r1,4:base,s36:260ca7e9-c6fa-4cc5-8de2-e05e68114e71,7:Cluster,1,4:Name,s21:ssc-db-clus.ssc.local,9:SqlServer,1,4:Name,s10:ssc-db-n3\,?zoom=1738282603991,1738308365189&amp;timeRange=12&amp;maxTime=1738308365189

FTP2It

 This issue is still occurring and it is very random when it happens. I've upgraded to 14.0.44.6696 and the issue still exists.

DonFerguson

The issue happens if it needs to display blocking information in the time window selected.  It's a bug that Redgate needs to fix.

DonFerguson

Actually, I may be wrong that Blocking is the trigger, but here is another link to Redgate's Live Demo that duplicates the issue:

ssc-db-n3\(local) - Server Overview

DonFerguson

@FTP2It, they just released 14.0.45 and this fixed it for me.

FTP2It

@DonFerguson, Great Thanks!