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EF6 transaction error in ObjectContext

please can someone help i'm trying to use Transaction in EF6. it's my first try in transaction in .net.
i have read the manual by Microsoft in their site.
http://msdn.microsoft.com/en-us/data/dn456843.aspx and i would to use a transaction for user registration but nothing is working. Im using EF objectContext.
here is a little piece of my code :
using (var context= new MyModelContainer())
{
using(var dbContextTransaction = context.Database.BeginTransaction())
{
try
{
// code here to create user
context.savechanges();
// code here to add role
context.savechanges();
dbContextTransaction.Commit();
}
catch
{
dbContextTransaction.Rollback();
}
}
}
My problem is that Visual Studio does not even recognize Database.BeginTransaction(). may be because we are using objectContext? i never use transaction. i change to use another database where our model is DbContext it's seems to work.
How can we use objectContext with transaction also (mean not distributed systems) ?
any tutorial please ?
I tried transaction scope but it's seem to work but i read that it's for distributed system ((( it's means that performance going down. any suggestion ?
thanks for your time !!!

Replace the line
using(var dbContextTransaction = context.Database.BeginTransaction())
with this:
using(var dbContextTransaction = new TransactionScope())
and remove the call to Rollback. TransactionScore will do what you need.
TransactionScope is compatible with distributed systems, but if you do not make a call to other db's and use it as described, then it is more than good enough for your needs. If you try to make a call to save to another db (for example) then it will require special privileges and an exception will be thrown.

Snapshot isolation in SQL / code blocking reads

I suspect I don't understand fully what's going on or something weird is happening. (The first case is more likely I guess.)
The big picture:
I'm trying to have a web-service perform certain operations asynchronously as they can be time consuming and I don't want the client to wait for the operations to finish (just query for the results every now and again to see the operation is done).
The async code is wrapped in a transaction - in case something goes wrong, I want to be able to rollback any changes.
Unfortunately the last step of the async code is to call a DIFFERENT service which queries the same database.
Despite wrapping the whole thing in a Snapshot transaction, the last step fails as the service cannot read from the database.
For that matter, while the async operation is underway I cannot perform a simple SELECT statements from the database either.
Here's a sample of the code which I'm currently using to test out the transactions (using Entity Framework 5 model first):
using (var transaction = new System.Transactions.TransactionScope(System.Transactions.TransactionScopeOption.RequiresNew, new System.Transactions.TransactionOptions() { IsolationLevel = System.Transactions.IsolationLevel.Snapshot }))
{
var db = new DataModelContainer();
Log test = new Log();
test.Message = "TEST";
test.Date = DateTime.UtcNow;
test.Details = "asd";
test.Type = "test";
test.StackTrace = "asd";
db.LogSet.Add(test);
db.SaveChanges();
using (var suppressed = new System.Transactions.TransactionScope(System.Transactions.TransactionScopeOption.Suppress))
{
var newDb = new DataModelContainer();
var log = newDb.LogSet.ToArray(); //deadlock here... WHY?
}
test = db.LogSet.Where(l => l.Message == "TEST").Single();
db.LogSet.Remove(test);
db.SaveChanges();
transaction.Complete();
}
The code creates a simple Log entry in the database (yeah, I'm playing around at the moment so the values are rubbish). I've set the SQL database to allow snapshot isolation, and to my knowledge reads should still be permitted (these are being tested in this code by using a new, suppressed transaction and a new DataModelContainer). However, I cannot query the LogSet in the suppressed transaction or in SQL Management Studio - the whole table is locked!
So... why? Why is it locked if the transaction scope is defined as such? I've also tried other isolation levels (like ReadUncommited) and I still cannot query the table.
Could someone please provide an explanation for this behavior?

In SSMS, set your current isolation level to SNAPSHOT and see if that corrects your problem - it's probably set to READ COMMITTED and would therefore still block due to pending updates.
Update:
You can allow READ COMMITTED to access versioned rows DB-wide by altering the following option (and avoiding having to constantly set the current isolation level to SNAPSHOT):
ALTER DATABASE MyDatabase
SET READ_COMMITTED_SNAPSHOT ON

How to prevent EntityFramework deadlock when concurrently running these two statements

Calls into my web service use the following code to ensure that the caller has a valid session. If a valid session found then it updates the session details and saves the changes. All simple enough and works fine.
// Create the Entity Framework context
using(MyContext ctx = CreateMyContext())
{
// Get the user session for the client session
UserSession session = (from us in context.UserSessions.Include("UserEntity")
where us.SessionId = callerSessionId
select us).FirstOrDefault<UserSession>();
if (session == null)
return false;
else
{
// Update session details
session.Calls++;
session.LastAccessed = DateTime.Now.Ticks;
Console.WriteLine("Call by User:{0}", session.UserEntity.Name);
// Save session changes back to the server
ctx.SaveChanges();
return true;
}
}
All works fine until the same caller, and hence the same session, makes multiple concurrent calls (which is perfectly valid to happen). In this case I sometimes get a deadlock. Using SQL Server Profiler I can see the following is happening.
Caller A performs the select and acquires a shared lock on the user session. Caller B performs the select and acquires a shared lock on the same user session. Caller A cannot perform its update because of Caller B's shared lock. Caller B cannot perform its update because of caller A's shared lock. Deadlock.
This seems like a simple and classic deadlock scenario and there must be a simple method to resolve it. Surely almost all real world applications have this same problem.But none of the Entity Frameworks books I have mention anything about deadlocks.

I found an article that talks about this HERE. It basically sounds like you can start and stop a transaction that surrounds your EF call... The block gives the following code example so credit goes to Diego B Vega... The blog post also links to another blog with additional information.
using (var scope = new TransactionScope(TransactionScopeOption.Required, new
TransactionOptions { IsolationLevel= IsolationLevel.Snapshot }))
{
// do something with EF here
scope.Complete();
}

Will the following work for you?
using(MyContext ctx = CreateMyContext())
{
ctx.Database.ExecuteSqlCommand("SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;");
// Get the user session for the client session
...
}

You probably have each session using a transaction maybe? in which case they will deadlock as the transactions both try to upgrade from shared lock to exclusive lock when they attempt to save. This seems to be not well documented since EF favours optimistic concurrency.
One way out of this is to provide an updatelock hint using something like this:
return context.TestEntities
.SqlQuery("SELECT TOP 1 Id, Value FROM TestEntities WITH (UPDLOCK)")
.Single();
}
see: entity framework 6 and pessimistic concurrency

How can i enable Transaction my codes with linqto SQL?

if writing below codes: Error returns.i do like advise : http://stackoverflow.com/questions/794364/how-do-i-use-transactionscope-in-c
But only error change:The partner transaction manager has disabled its support for remote/network transactions Exception from HRESULT: 0x8004D025
i am using windows server 2003.
using (var stockMovementCtx = new StockMovementCtxDataContext())
{
using (var scope = new TransactionScope())
{
// do something....
}
scope.Complete();
}
but if i changed my codes ; every thing is ok:
using (var stockMovementCtx = new StockMovementCtxDataContext())
{
// do something....
}
How can i solve below error. This is really important.Please help me:((((

TransactionScope will elevate to DTC if necessary. It sounds like DTC is not correctly configured, usually due to firewall restrictions. Try a dtcping between the servers (important: in both directions).

DataContext by default wraps all operations within a Transaction, so you don't need to explicitly do Transaction while working with DataContext. Read this.
http://weblogs.asp.net/scottgu/archive/2007/07/11/linq-to-sql-part-4-updating-our-database.aspx
using (var stockMovementCtx = new StockMovementCtxDataContext())
{
// do something....
//everything until this point is within the transaction.
stockMovementCtx.SubmitChange();
}
Why we need TransactionScope ?
TransactionScope enables you to perform transactions beyond dataabse. Say you have series of operations as below and all are atomic and they need be performed within a transaction.
1.) Add record in Table 1
2.) Add record in Table 2
3.) Write a NEW file on the Disk
4.) Rename file X on the disk
5.) Update file record in Table 3
If you use SqlTransaction then only the operaration 1,3 and 5 can participate in the transaction but 3 and 4 cannot because they do not relate database at all. In such cases TrasanctionScope can help you. TransactionScope leverages the MSDTC (Distributed Trasanction co-coordinator) that can help you do transactions beyond database context. You can wrap all five operations within a TransactionScope transaction execute them atomically. It is also worth noting that TransactionScope supports nested transactions, that means one block of transaction can contain multiple set of transactions.

"The operation is not valid for the state of the transaction" error and transaction scope

I am getting the following error when I try to call a stored procedure that contains a SELECT Statement:
The operation is not valid for the state of the transaction
Here is the structure of my calls:
public void MyAddUpdateMethod()
{
using (TransactionScope Scope = new TransactionScope(TransactionScopeOption.RequiresNew))
{
using(SQLServer Sql = new SQLServer(this.m_connstring))
{
//do my first add update statement
//do my call to the select statement sp
bool DoesRecordExist = this.SelectStatementCall(id)
}
}
}
public bool SelectStatementCall(System.Guid id)
{
using(SQLServer Sql = new SQLServer(this.m_connstring)) //breaks on this line
{
//create parameters
//
}
}
Is the problem with me creating another connection to the same database within the transaction?

After doing some research, it seems I cannot have two connections opened to the same database with the TransactionScope block. I needed to modify my code to look like this:
public void MyAddUpdateMethod()
{
using (TransactionScope Scope = new TransactionScope(TransactionScopeOption.RequiresNew))
{
using(SQLServer Sql = new SQLServer(this.m_connstring))
{
//do my first add update statement
}
//removed the method call from the first sql server using statement
bool DoesRecordExist = this.SelectStatementCall(id)
}
}
public bool SelectStatementCall(System.Guid id)
{
using(SQLServer Sql = new SQLServer(this.m_connstring))
{
//create parameters
}
}

When I encountered this exception, there was an InnerException "Transaction Timeout". Since this was during a debug session, when I halted my code for some time inside the TransactionScope, I chose to ignore this issue.
When this specific exception with a timeout appears in deployed code, I think that the following section in you .config file will help you out:
<system.transactions>
<machineSettings maxTimeout="00:05:00" />
</system.transactions>

I also come across same problem, I changed transaction timeout to 15 minutes and it works.
I hope this helps.
TransactionOptions options = new TransactionOptions();
options.IsolationLevel = System.Transactions.IsolationLevel.ReadCommitted;
options.Timeout = new TimeSpan(0, 15, 0);
using (TransactionScope scope = new TransactionScope(TransactionScopeOption.Required,options))
{
sp1();
sp2();
...
}

For any wanderer that comes across this in the future. If your application and database are on different machines and you are getting the above error especially when using TransactionScope, enable Network DTC access. Steps to do this are:
Add firewall rules to allow your machines to talk to each other.
Ensure the distributed transaction coordinator service is running
Enable network dtc access. Run dcomcnfg. Go to Component sevices > My Computer > Distributed Transaction Coordinator > Local DTC. Right click properties.
Enable network dtc access as shown.
Important: Do not edit/change the user account and password in the DTC Logon account field, leave it as is, you will end up re-installing windows if you do.

I've encountered this error when my Transaction is nested within another. Is it possible that the stored procedure declares its own transaction or that the calling function declares one?

For me, this error came up when I was trying to rollback a transaction block after encountering an exception, inside another transaction block.
All I had to do to fix it was to remove my inner transaction block.
Things can get quite messy when using nested transactions, best to avoid this and just restructure your code.

In my case, the solution was neither to increase the time of the "transactionscope" nor to increase the time of the "machineSettings" property of "system.transactions" of the machine.config file.
In this case there was something strange because this error only happened when the volume of information was very high.
So the problem was based on the fact that in the code inside the transaction there were many "foreach" that made updates for different tables (I had to solve this problem in a code developed by other personnel). If tests were performed with few records in the tables, the error was not displayed, but if the number of records was increased then the error was displayed.
In the end the solution was to change from a single transaction to several separate ones in the different "foreach" that were within the transaction.

You can't have two transactions open at the same time. What I do is that I specify transaction.Complete() before returning results that will be used by the 2nd transaction ;)

I updated some proprietary 3rd party libraries that handled part of the database process, and got this error on all calls to save. I had to change a value in the web.config transaction key section because (it turned out) the referenced transaction scope method had moved from one library to another.
There was other errors previously connected with that key, but I got rid of them by commenting the key out (I know I should have been suspicious at that point, but I assumed it was now redundant as it wasn't in the shiny new library).