"This SqlTransaction has completed; it is no longer usable."... configuration error?

Question

I've been working on this for about a day and a half now, and searched numberous blogs and help articles on the Web. I found several questions on SO related to this error, but I didn't think they quite applied to my situation (or in some cases, unfortunately, I couldn't understand them well enough to implement :P). I'm not sure I can describe this well enough for help... but here goes:

We have a .NET app to track our resources. There's an export function to copy a resource to the time tracking system and the billing system; this accesses a stored procedure that links to the time and billing databases.

I recently moved the billing system database to a new server (original server: Server 2003 SP2, SQL 2005; new server: Server 2008 R2, SQL 2008 R2). I have a Linked Server set up that points to the 2008 databases. I updated the stored procedure to point to the 2008 server, and then I got an error about MSDTC and RPC (http://www.safnet.com/writing/tech/archives/2007/06/server_myserver.html). I enabled 'rpc/rpc out' on the Linked Server and set MSDTC to allow Network Access (something like this: http://www.sqlwebpedia.com/content/msdtc-troubleshooting).

Now I'm getting the above, when I try to run the export function: "This SqlTransaction has completed; it is no longer usable." What seems odd to me is that when I just run the stored procedure (from SSMS), it says it completes successfully.

Has anyone seen this before? Have I missed something in the configuration? I keep going over the same pages, and the only thing I found was that I didn't reboot after making the MSDTC changes (mentioned in here: http://social.msdn.microsoft.com/forums/en-US/adodotnetdataproviders/thread/7172223f-acbe-4472-8cdf-feec80fd2e64/).

I can post part or all of the stored procedure, if it would help... please let me know.

Lollygag

https://mcmap.net/q/275271/-sqltransaction-has-completed – Optimist

Answer 1

I believe this error message is due to a "zombie transaction".

Look for possible areas where the transacton is being committed twice (or rolled back twice, or rolled back and committed, etc.). Does the .Net code commit the transaction after the SP has already committed it? Does the .Net code roll it back on encountering an error, then attempt to roll it back again in a catch (or finally) clause?

It's possible an error condition was never being hit on the old server, and thus the faulty "double rollback" code was never hit. Maybe now you have a situation where there is some configuration error on the new server, and now the faulty code is getting hit via exception handling.

Can you debug into the error code? Do you have a stack trace?

Frigg

looks like that's on the right track... I found another tool (dtctester) and my original error was due to a misconfiguration (I thought I'd checked the firewall on the new server... guess that's what I get for assuming). Looks like my new error matches what you're saying, "Transaction count after EXECUTE indicates that a COMMIT or ROLLBACK TRANSACTION statement is missing. Previous count = 1, current count = 2." I'll have to do a little more digging and get back to you. – Lollygag

I'm assuming there was a duplicate in the code... I commented out the Rollback Transaction in the stored procedure, and it looks like everything's working now. I'm waiting for the user to test, but it's getting past the point where it was erroring before. :) Thanks for the input! – Lollygag

I've run my code like 300 times during debugging today and this is the first time I've seen this error... – Kleptomania

Answer 2

I had this recently after refactoring in a new connection manager. A new routine accepted a transaction so it could be run as part of a batch, problem was with a using block:

public IEnumerable<T> Query<T>(IDbTransaction transaction, string command, dynamic param = null)
{
  using (transaction.Connection)
  {
    using (transaction)
    {
      return transaction.Connection.Query<T>(command, new DynamicParameters(param), transaction, commandType: CommandType.StoredProcedure);
    }
  }
}

It looks as though the outer using was closing the underlying connection thus any attempts to commit or rollback the transaction threw up the message "This SqlTransaction has completed; it is no longer usable."

I removed the usings added a covering test and the problem went away.

public IEnumerable<T> Query<T>(IDbTransaction transaction, string command, dynamic param = null)
{
  return transaction.Connection.Query<T>(command, new DynamicParameters(param), transaction, commandType: CommandType.StoredProcedure);
}

Check for anything that might be closing the connection while inside the context of a transaction.

Garwood

Answer 3

Had the exact same problem and just could not find the right solution. Hope this helps somebody.

I have an .NET Core 3.1 WebApi with EF Core. Upon receiving multiple calls at the same time, the applications was trying to add and save changes to the database at the same time.

In my case the problem was that the table that the data would be saved in, did not have a primary key set.

Somehow EF Core missed when the migration was ran from the application that the ID in the model was supposed to be a primary key.

I found the problem by opening the SQL Profiler and seeing that all transactions was successfully submitted to the database (from the application) but only one new row was created. The profiler also showed that some type of deadlock was happening but I couldn't see much more in the trace logs of the profiler. On further inspection I noticed that the primary key identifier was missing on the column "Id".

The exceptions I got from my application was:

This SqlTransaction has completed; it is no longer usable.

and/or

An exception has been raised that is likely due to a transient failure. Consider enabling transient error resiliency by adding 'EnableRetryOnFailure()' to the 'UseSqlServer' call.

Eimile

I had the same symptoms ("This SqlTransaction has completed; it is no longer usable" error) in .NET 5 with EF Core 5.06. But in my case the error started when I changed a table from a primary key of INT [Id] to a composite key. (Yes, the composite key was explicitly defined via Fluent API declaration.) When rapid operations were performed on the composite key table, about 10-20% of calls would fail with that error. Going back to a single numeric key eliminated the error. Just posting this in case it helps anyone. – Merci

This is absolutely the right answer. I never thought that not having primary key can trigger this issue, even though the column was identity. Added primary key and this problem is gone. Thanks a lot @Danny. – Scrivings

I am glad my answer helped you @PrashantGupta! – Eimile

Answer 4

I have the same problem. This error occurs because conection pooling. When exists two or more users acess the system the connetion pooling reuse a connetion and the transation too. If the first user execute commit ou rollback the transaction is no longe usable.

Affray

This seems to be my problem too as it only occurs when more than one user is in the application. Any ideas how to fix this? – Geraint

Answer 5

I have recently ran across similar situation. To debug in any VS IDE version, open exceptions from Debug (Ctrl + D, E) - check all checkboxes against the column "Thrown", and run the application in debug mode. I have realized that one of the tables was not imported properly in the new database, so internal Sql Exception was killing the connection, thus results into this error.

Gist of the story is, If Previously working code returns this error on a new database, this could be database schema missing issue, realize by above debugging tip,

Hope It Helps, HydTechie

Cognition

Thanks for the tip, going through a REALLY Baroque (Wheels within wheels within wheels .....) legacy application and this helped narrow down the issue – Tombac

In my case this was due to an error occurring in a stored procedure call embedded in another stored procedure. – Flung

Answer 6

Also check for any long running processes executed from your .NET app against the DB. For example you may be calling a stored procedure or query which does not have enough time to finish which can show in your logs as:

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

  • This SqlTransaction has completed; it is no longer usable.

Check the command timeout settings Try to run a trace (profiler) and see what is happening on the DB side...

Chelsiechelsy

This was our case. – Orcinol

Answer 7

Here is a way to detect Zombie transaction

SqlTransaction trans = connection.BeginTransaction();

//some db calls here

if (trans.Connection != null) //Detecting zombie transaction
{
  trans.Commit();
}

Decompiling the SqlTransaction class, you will see the following

public SqlConnection Connection
{
  get
  {
    if (this.IsZombied)
      return (SqlConnection) null;
    return this._connection;
  }
}

I notice if the connection is closed, the transOP will become zombie, thus cannot Commit. For my case, it is because I have the Commit() inside a finally block, while the connection was in the try block. This arrangement is causing the connection to be disposed and garbage collected. The solution was to put Commit inside the try block instead.

Attributive

Answer 8

In my case the problem was that one of the queries included in the transaction was raising an exception, and even though the exception was "gracefully" handled, it still managed to roll back the entire transaction.

My pseudo-code was like:

var transaction = connection.BeginTransaction();
for(all the lines in a file)
{
     try{
         InsertLineInTable(); // INSERT statement might fail and throw an exception
     }
     catch {
         // notify the user about the error on line x and continue
     }
}

// Commit and Rollback will fail if one of the queries 
// in InsertLineInTable threw an exception
if(CheckTableForErrors())
{
    transaction.Commit();
}
else
{
    transaction.Rollback();
}

Consubstantiate

Answer 9

In my case, I've some codes which need to execute after committing the transaction, at the same try-catch block. One of the codes threw an error then try block handed over the error to its catch block which contains the transaction rollback. It will show a similar error. For example, look at the code structure below :

SqlTransaction trans = null;

try{
 trans = Con.BeginTransaction();
// your codes

  trans.Commit();
//your codes having errors

}
catch(Exception ex)
{
     trans.Rollback(); //transaction roll back
    // error message
}

finally
{ 
    // connection close
}

Hope it will help someone :)

Security

Answer 10

For what it's worth, I've run into this on what was previously working code. I had added SELECT statements in a trigger for debug testing and forgot to remove them. Entity Framework / MVC doesnt play nice when other stuff is output to the "grid". Make sure to check for any rogue queries and remove them.

Sphenic