While debugging the issues described in my previous post, I looked at how the ESB.Exceptions.Service’s GetFaults() method was implemented. In our case, we had stack traces inside the Description text, so the size of the data returned for each fault was quite large. Multiplied by thousands of faults, this is why we overflowed the default setting for maxItemsInObjectGraph.
However, this raised an important question: why was the value for Description (and many other fields) being returned from the service when the web pages never show it?
The answer? The service’s GetFaults() method returns every column from the Fault table, including potentially large values like ExceptionStackTrace, ExceptionMessage and Description. These fields are never used by the ESB Portal, so this behavior only serves to slow down the queries and cause issues like that described in my last post!
I modified the GetFaults() method’s Linq query to select only the columns used in the portal:
select new
{
f.Application,
f.DateTime,
f.ErrorType,
f.FailureCategory,
f.FaultCode,
f.FaultGenerator,
f.FaultID,
f.FaultSeverity,
f.InsertMessagesFlag,
f.MachineName,
f.Scope,
f.ServiceName
};
And then created the actual Fault objects just before returning from the method:
List<Fault> faults = new List<Fault>(); foreach (var fault in result) { Fault f = new Fault() { Application = fault.Application, DateTime = fault.DateTime, ErrorType = fault.ErrorType, FailureCategory = fault.FailureCategory, FaultCode = fault.FaultCode, FaultGenerator = fault.FaultGenerator, FaultID = fault.FaultID, FaultSeverity = fault.FaultSeverity, InsertMessagesFlag = fault.InsertMessagesFlag, MachineName = fault.MachineName, Scope = fault.Scope, ServiceName = fault.ServiceName }; faults.Add(f); } return faults;
This avoids the expense of SQL Server selecting many large data values that are never used, and can greatly reduce the amount of data that must be serialized and de-serialized across the service boundary.
This change provided a very noticeable boost in performance on the Faults page when searching, filtering and moving between pages.
