Hi, our DNN 08.00.04 (226) instance on an AWS server has been running very slowly, at times using up all the CPU. 

I have been investigating the events logs and fixing a few things like deleted/unused modules still enabled in the scheduler and speed has improved.  However, still get some scheduler exceptions (shown below) and wondered if any of you have any inkling as to what it may be.

DefaultDataProvider:DotNetNuke.Data.SqlDataProvider, DotNetNuke

ExceptionGUID:2c226a29-51a2-49d1-80dc-6f61de3d9f00

AssemblyVersion:

PortalId:-1

UserId:-1

TabId:-1

RawUrl:

Referrer:

UserAgent:

ExceptionHash:4MIHdTOFqbZ5ODAqHGCagQ==

Message:Execution Timeout Expired. The timeout period elapsed prior to completion of the operation or the server is not responding.

StackTrace:

   at System.Data.SqlClient.SqlConnection. (SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction)
   at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose)
   at System.Data.SqlClient.TdsParser.TryRun(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj, Boolean& dataReady)
   at System.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString, Boolean isInternal, Boolean forDescribeParameterEncryption, Boolean shouldCacheForAlwaysEncrypted)
   at System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async, Int32 timeout, Task& task, Boolean asyncWrite, Boolean inRetry, SqlDataReader ds, Boolean describeParameterEncryptionRequest)
   at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, TaskCompletionSource`1 completion, Int32 timeout, Task& task, Boolean& usedCache, Boolean asyncWrite, Boolean inRetry)
   at System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(TaskCompletionSource`1 completion, String methodName, Boolean sendToPipe, Int32 timeout, Boolean& usedCache, Boolean asyncWrite, Boolean inRetry)
   at System.Data.SqlClient.SqlCommand.ExecuteNonQuery()
   at PetaPoco.Database.Execute(String sql, Object[] args)
   at DotNetNuke.Data.SqlDataProvider.ExecuteNonQuery(String procedureName, Object[] commandParameters)
   at DotNetNuke.Data.DataProvider.UpdateScheduleHistory(Int32 ScheduleHistoryID, DateTime EndDate, Boolean Succeeded, String LogNotes, DateTime NextStart)
   at DotNetNuke.Services.Scheduling.SchedulingController.UpdateScheduleHistory(ScheduleHistoryItem objScheduleHistoryItem)
   at DotNetNuke.Services.Scheduling.Scheduler.CoreScheduler.UpdateScheduleHistory(ScheduleHistoryItem scheduleHistoryItem)

InnerMessage:The wait operation timed out

InnerStackTrace:

Source:.Net SqlClient Data Provider