I have an intermittent Devart.Data.Linq.ChangeConflictException: Row not found or changed raising it's ugly head. The funny thing is, the change is still written to the database!
The stack trace says:
Devart.Data.Linq.ChangeConflictException: Row not found or changed.
at Devart.Data.Linq.Engine.b4.a(IObjectEntry[] A_0, ConflictMode A_1, a A_2)
at Devart.Data.Linq.Engine.b4.a(ConflictMode A_0)
at Devart.Data.Linq.DataContext.SubmitChanges(ConflictMode failureMode)
at Devart.Data.Linq.DataContext.SubmitChanges()
at Billing.Eway.EwayInternal.SuccessCustomerRenewal(String username, Bill bill, EwayTransaction transaction) in c:\Users\Ian\Source\Repos\billing-class-library\Billing\Billing\Eway\EwayInternal.cs:line 552
at Billing.Eway.Eway.BillAllUsers() in c:\Users\Ian\Source\Repos\billing-class-library\Billing\Billing\Eway\Eway.cs:line 138
And my code for Billing.Eway.EwayInternal.SuccessCustomerRenewal:
internal static void SuccessCustomerRenewal(string username, Bill bill, EwayTransaction transaction)
{
// Give them their points!
ApplyBillToCustomerAccount(username, bill, true);
BillingEmail.SendRenewalSuccessEmail(username, bill, transaction);
using (MsSqlDataClassesDataContext msSqlDb = new MsSqlDataClassesDataContext())
{
// TODO: Remove this logging
msSqlDb.Log = new StreamWriter(#"logs\db\" + Common.GetCurrentTimeStamp() + "-MsSQL.txt", true) { AutoFlush = true };
EwayCustomer ewayCustomer = msSqlDb.EwayCustomers.First(c => c.Username == username);
ewayCustomer.NextBillingDate = Common.GetPlanExpiry(bill.BillPlan);
using (MySqlDataContext mySqlDb = new MySqlDataContext())
{
// TODO: Remove this logging
mySqlDb.Log = new StreamWriter(#"logs\db\" + Common.GetCurrentTimeStamp() + "-MySQL.txt", true) { AutoFlush = true };
BillingMySqlContext.Customer grasCustomer = mySqlDb.Customers.First(c => c.Username == username);
// Extend their membership date out so that the plan doesn't expire because of a failed credit card charge.
grasCustomer.MembershipDate =
ewayCustomer.NextBillingDate.AddDays(1);
mySqlDb.SubmitChanges(); // <-- This is line 552
}
msSqlDb.SubmitChanges();
}
}
I know that the issue occurs on the mySqlDb.SubmitChanges() line, since that DB context is the one using Devart (Linq solution for MySQL databases): the other context uses pure MS Linq.
Not only is the change written to the MySql DB (inner using block), but it is also written to the MsSql DB (outer using block). But that's where the magical success ends.
If I could I would write a Minimal, Complete and Verifiable example, but strangely I'm unable to generate a Devart ChangeConflictException.
So, why does the change get saved to the database after a Devart.Data.Linq.ChangeConflictException? When I previously encountered System.Data.Linq.ChangeConflictException changes weren't saved.
Edit 1:
I've also now included the .PDB file and gotten line number confirmation of the exact source of the exception.
Edit 2:
I now understand why I can't generate a ChangeConflictException, so how is it happening here?
These are the attributes for MembershipDate:_
[Column(Name = #"Membership_Date", Storage = "_MembershipDate", CanBeNull = false, DbType = "DATETIME NOT NULL", UpdateCheck = UpdateCheck.Never)]
I know I can explicitly force my changes through to override any potential conflict, but that seems undesirable (I don't know what I would be overriding!). Similarly I could wrap the submit in a try block, and retry (re-reading each time) until success, but that seems clunky. How should I deal with this intermittent issue?
Edit 3:
It's not caused by multiple calls. This function is called in one place, by a single-instance app. It creates log entries every time it is run, and they are only getting created once. I have since moved the email call to the top of the method: the email only gets sent once, the exception occurs, and database changes are still made.
I believe it has something to do with the using blocks. Whilst stepping through the debugger on an unrelated issue, I entered the using block, but stopped execution before the SubmitChanges() call. And the changes were still written to the database. My understanding was that using blocks were to ensure resources were cleaned up (connections closed, etc), but it seems that the entire block is being executed. A new avenue to research...
But it still doesn't answer how a ChangeConflictException is even possible given Devart explicitly ignores them.
Edit 4:
So I wasn't going crazy, the database change did get submitted even after I ended execution in the middle of the using block, but it only works for websites.
Edit 5:
As per #Evk's suggestion I've included some DB logging (and updated the stacktrace and code snippet above). The incidence rate of this exception seems to have dropped, as it has only just happened since I implemented the logging. Here are the additional details:
Outer (MS SQL) logfile:
SELECT TOP (1) [t0].[id], [t0].[Username], [t0].[TokenId], [t0].[PlanId], [t0].[SignupDate], [t0].[NextBillingDate], [t0].[PaymentType], [t0].[RetryCount], [t0].[AccountStatus], [t0].[CancelDate]
FROM [dbo].[EwayCustomer] AS [t0]
WHERE [t0].[Username] = #p0
-- #p0: Input NVarChar (Size = 4000; Prec = 0; Scale = 0) [dyonis]
-- Context: SqlProvider(Sql2008) Model: AttributedMetaModel Build: 4.0.30319.18408a
(It just shows the SELECT call (.First()), none of the updates show).
Inner (MySQL) logfile:
SELECT t1.Customer_ID, t1.Username, t1.Account_Group, t1.Account_Password, t1.First_Name, t1.Last_Name, t1.Account_Type, t1.Points, t1.PromoPoints, t1.Phone, t1.Cell, t1.Email, t1.Address1, t1.Address2, t1.City, t1.State, t1.Country, t1.Postcode, t1.Membership_Group, t1.Suspend_On_Zero_Points, t1.Yahoo_ID, t1.MSN_ID, t1.Skype_ID, t1.Repurchase_Thresh, t1.Active, t1.Delete_Account, t1.Last_Activity, t1.Membership_Expires_After_x_Days, t1.Membership_Date, t1.auth_name, t1.created_by, t1.created_on, t1.AccountGroup_Points_Used, t1.AccountGroup_Points_Threashold, t1.LegacyPoints, t1.Can_Make_Reservation, t1.Gallery_Access, t1.Blog_Access, t1.Private_FTP, t1.Photometrica, t1.Promo_Code, t1.Promo_Expire_DTime, t1.Gift_FirstName, t1.Gift_LastName, t1.Gift_Email, t1.Gift_Phone, t1.Gift_Active, t1.NoMarketingEmail, t1.Can_Schedule, t1.Refered_By, t1.Q1_Hear_About_Us, t1.Q2_Exp_Level, t1.Q3_Intrests, t1.GIS_DTime_UTC, t1.Membership_Expire_Notice_Sent, t1.Promo_Expire_Notice_Sent, t1.isEncrypted, t1.PlanId
FROM grasbill.customers t1
WHERE t1.Username = :p0 LIMIT 1
-- p0: Input VarChar (Size = 6; DbType = AnsiString) [dyonis]
-- Context: Devart.Data.MySql.Linq.Provider.MySqlDataProvider Mapping: AttributeMappingSource Build: 4.4.519.0
UPDATE grasbill.customers SET Membership_Date = :p1 WHERE Customer_ID = :key1
-- p1: Input DateTime (Size = 0; DbType = DateTime) [8/3/2016 4:42:53 AM]
-- key1: Input Int (Size = 0; DbType = Int32) [7731]
-- Context: Devart.Data.MySql.Linq.Provider.MySqlDataProvider Mapping: AttributeMappingSource Build: 4.4.519.0
(Shows the SELECT and UPDATE calls)
So the log files don't really give any clue as to what's happening, but again the MS SQL database has been updated! The NextBillingDate field has been set correctly, as per this line:
ewayCustomer.NextBillingDate = Common.GetPlanExpiry(bill.BillPlan);
If it hadn't been updated, the user would have been billed again on the next timer tick (5 mins later), and I can see from logging that didn't happen.
One other interesting thing to note is the log file timestamps. As you can see from the code above I grab the current (UTC) time for the log filename. Here is the information shown by Windows File Explorer:
The MS SQL logfile was created at 04:42 (UTC) and last modified at 14:42 (UTC+10, Windows local-time), but the MySQL logfile was last modified at 15:23 (UTC+10), 41 minutes after it was created. Now I assume the logfile StreamWriter is closed as soon as it leaves scope. Is this delay an expected side effect of the exception? Did it take 41 minutes for the garbage collector to realise I no longer needed a reference to the StreamWriter? Or is something else going on?
Well 6 months later I finally got to the bottom of this problem. Not sure if it will ever help anyone else, but I'll detail it anyway.
There were 2 problems in play here, and 1 of them was idiocy (as they usually are), but one was legitimately something I did not know or expect.
Problem 1
The reason the changes were magically made to the database even though there was an exception was because the very first line of code in that function ApplyBillToCustomerAccount(username, bill, true); updates the database! <facepalm>
Problem 2
The (Devart) ChangeConflictException isn't only thrown if the data has changed, but also if you're not making any changes. MS SQL stores DateTimes with great precision, but MySQL (or the one I'm running at least) only stores down to seconds. And here's where the intermittency came in. If my database calls were quick enough, or just near the second boundary, they both got rounded to the same time. Devart saw no changes to be written, and threw a ChangeConflictException.
I recently made some optimisations to the database which resulted in far greater responsiveness, and massively increased incidence of this exception. That was one of the clues.
Also I tried changing the Found Rows parameter to true as instructed in the linked Devart post but found it did not help in my case. Or perhaps I did it wrong. Either way now that I've found the source of the issue I can eliminate the duplicate database updates.
I'm trying to read an ESE database (.edb) using the ManagedEsent libraries. However, I'm getting an error at the time of setting up the database. The error appears to be coming up at the time of attaching the database (calling JetAttachDatabase()).
The error message I'm getting is "Soft recovery is intended on a backup database. Restore should be used instead".
Below is my code:
JET_INSTANCE instance;
JET_SESID sesid;
Microsoft.Isam.Esent.Interop.SystemParameters.DatabasePageSize = 8 * 1024;
Api.JetCreateInstance(out instance, Guid.NewGuid().ToString());
Api.JetInit(ref instance);
JET_DBID dbid;
JET_COLUMNID columnid;
JET_TABLEID tableid;
JET_COLUMNDEF columndef = new JET_COLUMNDEF();
Api.JetBeginSession(instance, out sesid, null, null);
Api.JetAttachDatabase(sesid, #"Blah.edb", AttachDatabaseGrbit.None);
Api.OpenDatabase(sesid, #"Blah.edb", out dbid, OpenDatabaseGrbit.None);
The exception I'm getting is:
Microsoft.Isam.Esent.Interop.EsentSoftRecoveryOnBackupDatabase
Soft recovery is intended on a backup database. Restore should be used instead
at Microsoft.Isam.Esent.Interop.Api.Check(Int32 err) in e:\src\codeplex_svn\codeplex\EsentInterop\Api.cs:line 2894
at Microsoft.Isam.Esent.Interop.Api.JetAttachDatabase(JET_SESID sesid, String database, AttachDatabaseGrbit grbit) in e:\src\codeplex_svn\codeplex\EsentInterop\Api.cs:line 372
Any ideas what could be causing this? Is the .edb file I'm attaching possible invalid?
I was able to access the database after running the EsentUtl utility to repair the database file:
esentutl /p Blah.edb
After running this, I can attach/open the database and read from the tables in the database.
I'm not sure what the repair has actually done to the file though (e.g. if it is possibly now missing some data or something).
Where did you get the database?
What you did should work for a Cleanly-shut-down database. You don't need the transaction log files for these databases.
But there are also Dirty databases (when JetTerm didn't complete gracefully). You'll need the transaction log files for those.
And also Backed-up databases, which are slightly different again. For these databases, you need to call JetRestore.
-martin
So essentially, I installed a NuGet Package in C# ASP.Net (Day Pilot Scheduler), purely for testing purposes.
Now though, after removing it completely from my Website, I am continually getting the same errors, with assembly references etc.. (There is literally nothing wrong with them as I haven't changed ANYTHING regarding them.
Account account = new Account();
Job job = new Job();
int jb = (from j in context.Job
where j.jobType == "Customer"
select j.jobId).Single();
account.username = registerUsernameTxtbox.Text.ToString();
account.password = registerPasswordTxtbox.Text.ToString();
account.Job = jb;
context.Account.Add(account);
context.SaveChanges();
The code that is getting the errors on it is appearing on, is anything that references the class 'Account'. (so it appears on 'Account', 'username', 'password' and 'Job'
context also appears with an error, which also baffles me because I created an instance and the instance is fine.
Here is an image of the issues showing the errors too.
http://i.imgur.com/tE9YuH7.png
With error '7'. I have attempted to delete the folder it states, and it appears again after reopening the website.
I have also removed everything regarding DayPilotScheduler too but still failed on removing these errors.
Does anyone have any idea for this? I have googled it but failed to find any information regarding this.
this was due to having a "table" called 'Account' in one Class, and a webform called Account it seems. It removed the initial errors, and left me with a few more (ones that I think I should be able to fix.).
Using Windows Serives Bus (not the cloud version), I'm trying to rename a topic programatically, so far I have
internal void UpdateTopic(Topic Topic)
{
Topic dbTopic = TopicManager.GetTopicById(Topic.Id);
TopicDescription topicDescription = _namespaceManager.GetTopic(dbTopic.Name);
topicDescription.Path = Topic.Name;
topicDescription.Status = Topic.Active ? EntityStatus.Active : EntityStatus.Disabled;
_namespaceManager.UpdateTopic(topicDescription);
...
The line _namespaceManager.UpdateTopic(topicDescription); throws Exception The remote server returned an error: (404) Not Found. Not Found.TrackingId:[some tracking id including a GUID],TimeStamp:20/12/2013 13:29:47
Questions:
- Can I actually rename a topic programmatically?
If yes:
- Any idea of what causes the exception?
Rename of a Topic is not supported. You can do Create, Update and Delete operations but since the name is the identifier of the particular resource it cannot be modified. There are several other properties on a TopicDescriptiontoo that cannot be modified, but only set at the time of creation (such as Size).
I have inherited an application that runs small reports locally using Microsoft Web ReportViewer. Our application allows you to "Preview/Print" a report by clicking on a specific button that routes the user to a URL that allows them to download the report as a PDF. We have recently received the requirement to save these PDFs to the document table in our database. I have been able to get this to work successfully on localhost; however, when I publish the application to our IIS server, I get the following error:
System.Data.SqlClient.SqlException: Login failed for user 'Domain\Servername$'.
I've reviewed all of the sites that I could find involving this error (including this one) - most point to adding the server account to the SQL database; however, this shouldn't be an issue, since the button to preview/print the document is still functional and works as expected when the application is published and all of the data is held in a local object, which was previously pulled from the database (the model parameter below). The button and the auto-generation feature use the same two methods to create the PDF document(see below).
Here's some code:
public static byte[] CreatePDFDocument(DocumentTemplateType template, Request model)
{
Warning[] warnings;
string[] streamIds;
string mimeType = string.Empty;
string encoding = string.Empty;
string extension = string.Empty;
ReportViewer viewer = new ReportViewer();
viewer.ProcessingMode = ProcessingMode.Local;
viewer.LocalReport.ReportEmbeddedResource = "Xxx.Xxx.Bll.ReportViewerRDLCs." + template.RdlcFilename;
switch ((DocumentType)template.DocumentTypeId)
{
case eDocumentType.Report1:
viewer.LocalReport.SetParameters(GetForm1Parameters(model));
break;
/**
* Several other reports are in this switch. All reports have the
* same issue - all but one are removed for brevity.
*/
}
byte[] bytes = viewer.LocalReport.Render("PDF", null, out mimeType, out encoding, out extension, out streamIds, out warnings);
return bytes;
//return new byte[5] {5,6,7,8,9}; - used for troubleshooting.
}
public static List<ReportParameter> GetReport1Parameters(Request model)
{
List<ReportParameter> rptParams = new List<ReportParameter>();
//Start comment
rptParams.Add(new ReportParameter("EmployeeFullName", string.Format("{0:NN}", model.Employee)));
rptParams.Add(new ReportParameter("EmployeePhoneNumber", string.Format("{0:(###) ###-####}", Convert.ToInt64(model.Employee.PhoneNumber))));
rptParams.Add(new ReportParameter("HrchyShortDesc", model.Employee.HrchyShortDesc));
rptParams.Add(new ReportParameter("RequestDate", model.RequestDate.ToShortDateString()));
rptParams.Add(new ReportParameter("RequestRequested", model.RequestRequestType));
rptParams.Add(new ReportParameter("ReasonForRequest", model.RequestRequestReason));
rptParams.Add(new ReportParameter("LogNumber", model.CaseId));
if (!string.IsNullOrWhiteSpace(model.TimeSensitiveReason)) rptParams.Add(new ReportParameter("TimeSensitiveReason", model.TimeSensitiveReason));
var lastAction = model.LastActionOfType(WorkflowStateActionType.EmployeeConfirmation);
if (lastAction != null)
{
rptParams.Add(new ReportParameter("TodaysDate", lastAction.ActionDate.ToShortDateString()));
rptParams.Add(new ReportParameter("EmpConfirmed", "true"));
}
else rptParams.Add(new ReportParameter("TodaysDate", DateTime.Now.ToShortDateString()));
//end comment
return rptParams;
}
Through a lot of commenting in and out and pushes to our server, I've deduced the following:
From what I can tell, the error occurs on calling GetReport1Parameters. In the code above, I included a start and end comment - I've commented out everything in between, leaving only the list initialization and return statement (of an empty list) and still received the error.
I've commented out the call to GetReport1Parameters and returned a nonsensical byte array and didn't receive an Exception.
All functionality works fine on localhost and when I step through the functions, all of the variables seem to appear normal.
Things I've tried to do to remedy the situation:
1. Removed connection strings from the app.config, so that the application has to go to the web.config to get the correct strings (even though they were the same).
2. Commented in and out different sections of code to determine the problem area.
3. Tried calling the GetReport1Parameters method and returning null, leading to a null reference exception.
4. Tried calling the GetReport1Parameters with an empty parameter list, leading to the error mentioned above.
5. Tried running the report with no parameters (not even a blank list), got a ReportProcessingException for missing params.
Some additional information:
We use a service account for the application using impersonate identity in the web.config. That line is commented out on localhost, but is running on IIS.
All of other database interaction works correctly.
All of our database interaction is done using LINQ to SQL - model is an object based off of a database table, with some additional information that is calculated dynamically.
My desired outcome is that both the autogenerated documents and the preview/print documents both work. I have a feeling that this may be something simple that I'm overlooking, but I've already spent several hours today trying to fix this.
I can't think of any other pertinent information, but if you have questions I'll be more than happy to answer them.
Edit: Additional attempts to find solution:
Tried setting LINQ Deferred Loading equal to false. This caused more problems than it solved.
Implemented IReportServerCredentials and assigned the ReportViewer's ServerReport.ReportServerCredentials with the correct database credentials.
Assigned all pertinent report parameters to a Dictionary, and then called .ToString() on every object to ensure that it is pulled from the database. Then assigned those strings from the dictionary to the report parameters, so that ReportViewer should be receiving the data from the string pool, as opposed to pulling it from the database.
Even though you are using an ObjectDataSource to pass data to your report, Report Viewer will still invoke the Select method, which in turn could cause database access to occur. So even though it may seem that the login is unnecessary, you would need to dig into the data access methods you supplied with your ObjectDataSource to know for sure.
The error you are getting is being caused by a bug in Report Viewer 2010 that is describe in the following Microsoft Connect article:
ReportViewer.LocalReport.Render and ReportViewer.LocalReport.SetParameters changes ImpersonationLevel to None
Although the article mentions this problem should be fixed in Service Pack 1, it does not appear to be the case. I have not verified if this problem is fixed in Report Viewer 2012.
I worked around the problem by changing my data access layer to compare the current identity against the one in my HttpContext and restore it if necessary using the following code snippet:
System.Security.Principal.IIdentity id = System.Web.HttpContext.Current.User.Identity
if (id.Name != System.Security.Principal.WindowsIdentity.GetCurrent().Name)
{
context = (id as System.Security.Principal.WindowsIdentity).Impersonate()
}
I do this right before I connect to the database and undo it as soon as the connection is open.
I am not exactly thrilled with this workaround, mainly because now my data access layer is referencing the UI layer (System.Web).