This relates to SQL Server 2008.
I am writing a procedure that moves data from a production database to a periodic cache database for BI purposes.
Both databases are on the same SQL instance, hence I plan to avoid using SSIS at this stage.
I need to:
Remove all existing data from the cache.
Select all business branches into a table.
Select all sales divisions into a table
Select and transform the actual data.
If any of 2 - 4 fail, then I need to rollback and return a text error. So that the data in the cache remains as it was before the procedure was called.
I have looked at:
Stored Procedure Transaction
I thought the try, catch might be overkill.
What would be the best practice for this?
Is it as simple as using
BEGIN TRANSACTION
-- Do stuff
IF ##ERROR <> 0
ROLLBACK TRANSACTION
COMMIT TRANSACTION
Edit - This post is very useful as well:
How does SQL Server treat statements inside stored procedures with respect to transactions?
I would use the following approach:
First, I'd use the TRY CATCH syntax within a stored procedure.
Instead of removing all existing data I would rename the tables (cache, business branches, and sales divisions) and create new ones with the same name and format.
I'm not sure how complicated step 4 is. But if it's rather straight forward I'd place it in a separate transaction within the TRY CATCH block to allow the rollback.
If any of the code block fails, it'll jump to the CATCH section. Within that section I'd rollback step 4 (if needed), drop the newly created tables and rename the old ones.
Edit: and if there wasn't any error, drop the renamed tables.
As for the transactional part I'd go for a try catch solution to deal with the transaction scopes
http://msdn.microsoft.com/en-us/library/ms175976.aspx
BEGIN TRANSACTION;
BEGIN TRY
-- Generate a constraint violation error.
DELETE FROM Production.Product
WHERE ProductID = 980;
END TRY
BEGIN CATCH
SELECT
ERROR_NUMBER() AS ErrorNumber
,ERROR_SEVERITY() AS ErrorSeverity
,ERROR_STATE() AS ErrorState
,ERROR_PROCEDURE() AS ErrorProcedure
,ERROR_LINE() AS ErrorLine
,ERROR_MESSAGE() AS ErrorMessage;
IF ##TRANCOUNT > 0
ROLLBACK TRANSACTION;
END CATCH;
IF ##TRANCOUNT > 0
COMMIT TRANSACTION;
GO
I have an Insert stored procedure which will feed data to Table1 and get the Column1 value from Table1 and call the second stored procedure which will feed the Table2.
But when I call The second stored procedure as:
Exec USPStoredProcName
I get the following error:
Transaction count after EXECUTE indicates a mismatching number of BEGIN and COMMIT statements. Previous count = 1, current count = 0.
I have read the answers in other such questions and am unable to find where exactly the commit count is getting messed up.
If you have a TRY/CATCH block then the likely cause is that you are catching a transaction abort exception and continue. In the CATCH block you must always check the XACT_STATE() and handle appropriate aborted and uncommitable (doomed) transactions. If your caller starts a transaction and the calee hits, say, a deadlock (which aborted the transaction), how is the callee going to communicate to the caller that the transaction was aborted and it should not continue with 'business as usual'? The only feasible way is to re-raise an exception, forcing the caller to handle the situation. If you silently swallow an aborted transaction and the caller continues assuming is still in the original transaction, only mayhem can ensure (and the error you get is the way the engine tries to protect itself).
I recommend you go over Exception handling and nested transactions which shows a pattern that can be used with nested transactions and exceptions:
create procedure [usp_my_procedure_name]
as
begin
set nocount on;
declare #trancount int;
set #trancount = ##trancount;
begin try
if #trancount = 0
begin transaction
else
save transaction usp_my_procedure_name;
-- Do the actual work here
lbexit:
if #trancount = 0
commit;
end try
begin catch
declare #error int, #message varchar(4000), #xstate int;
select #error = ERROR_NUMBER(), #message = ERROR_MESSAGE(), #xstate = XACT_STATE();
if #xstate = -1
rollback;
if #xstate = 1 and #trancount = 0
rollback
if #xstate = 1 and #trancount > 0
rollback transaction usp_my_procedure_name;
raiserror ('usp_my_procedure_name: %d: %s', 16, 1, #error, #message) ;
end catch
end
go
I had this problem too. For me, the reason was that I was doing
return
commit
instead of
commit
return
in one stored procedure.
This normally happens when the transaction is started and either it is not committed or it is not rollback.
In case the error comes in your stored procedure, this can lock the database tables because transaction is not completed due to some runtime errors in the absence of exception handling
You can use Exception handling like below. SET XACT_ABORT
SET XACT_ABORT ON
SET NoCount ON
Begin Try
BEGIN TRANSACTION
//Insert ,update queries
COMMIT
End Try
Begin Catch
ROLLBACK
End Catch
Source
Be aware of that if you use nested transactions, a ROLLBACK operation rolls back all the nested transactions including the outer-most one.
This might, with usage in combination with TRY/CATCH, result in the error you described. See more here.
This can also occur if your stored procedure encounters a compile failure after opening a transaction (e.g. table not found, invalid column name).
I found i had to use 2 stored procedures a "worker" one and a wrapper one with try/catch both with logic similar to that outlined by Remus Rusanu. The worker catch is used to handle the "normal" failures and the wrapper catch to handle compile failure errors.
https://msdn.microsoft.com/en-us/library/ms175976.aspx
Errors Unaffected by a TRY…CATCH Construct
The following types of errors are not handled by a CATCH block when they occur at the same level of execution as the TRY…CATCH construct:
Compile errors, such as syntax errors, that prevent a batch from running.
Errors that occur during statement-level recompilation, such as object name resolution errors that occur after compilation because of deferred name resolution.
Hopefully this helps someone else save a few hours of debugging...
In my case, the error was being caused by a RETURN inside the BEGIN TRANSACTION. So I had something like this:
Begin Transaction
If (#something = 'foo')
Begin
--- do some stuff
Return
End
commit
and it needs to be:
Begin Transaction
If (#something = 'foo')
Begin
--- do some stuff
Rollback Transaction ----- THIS WAS MISSING
Return
End
commit
For me after extensive debugging the fix was a simple missing throw; statement in the catch after the rollback. Without it this ugly error message is what you end up with.
begin catch
if ##trancount > 0 rollback transaction;
throw; --allows capture of useful info when an exception happens within the transaction
end catch
I had the same error message, my mistake was that I had a semicolon at the end of COMMIT TRANSACTION line
Avoid using
RETURN
statement when you are using
BEGIN TRY
...
END TRY
BEGIN CATCH
...
END CATCH
and
BEGIN, COMMIT & ROLLBACK
statements in SQL stored procedures
I encountered this error once after omitting this statement from my transaction.
COMMIT TRANSACTION [MyTransactionName]
In my opinion the accepted answer is in most cases an overkill.
The cause of the error is often mismatch of BEGIN and COMMIT as clearly stated by the error. This means using:
Begin
Begin
-- your query here
End
commit
instead of
Begin Transaction
Begin
-- your query here
End
commit
omitting Transaction after Begin causes this error!
Make sure you don't have multiple transactions in the same procedure/query out of which one or more are left uncommited.
In my case, I accidentally had a BEGIN TRAN statement in the query
This can also depend on the way you are invoking the SP from your C# code. If the SP returns some table type value then invoke the SP with ExecuteStoreQuery, and if the SP doesn't returns any value invoke the SP with ExecuteStoreCommand
For me, the issue was that I forgot to add the output keyword following some output parameters of a SP call within the transaction.
The exact reason for this message is the rule that SQL Server implies: Transaction count should be same at the beginning and the end of execution of a procedure. In other terms, a procedure;
shouldn't commit/rollback a transaction that it didn't start. In this case, previous count displayed in the exception message would be greater zero, and current count is zero. Best way to prevent this is capturing transaction count (##TRANCOUNT) at the very beginning of the execution, and using transaction statements only if it is zero. The sample procedure below is a simplest "safe" structure against this type of mistake. If this procedure is called within an existing transaction, it won't begin a new transaction nor try to commit or rollback the "inherited" one. Instead, it just re-throws the same error to caller context. This is also a good practice to keep the real source procedure of the error.
should decide the fate (commit or rollback) of a transaction it started, before it's execution ends. In this case, current count would be greater than previous count.
I would highly recommend reading Erland Sommarskog's Error and Transaction Handling in SQL Server thoroughly
create or alter proc sp_err266
as
begin
set nocount on
set xact_abort on
declare #trancount int = ##trancount
if #trancount = 0
begin tran
begin try
raiserror('Raise an unexpected error...', 16, 1);
if XACT_STATE() = 1 and #trancount = 0
commit;
end try
begin catch
if XACT_STATE() <> 0 and #trancount = 0
rollback;
else
throw;
end catch
end
If you are having a code structure of something like:
SELECT 151
RETURN -151
Then use:
SELECT 151
ROLLBACK
RETURN -151
For me two begin transactions and multi rollback transaction causing this issue.
------------------------------------------------------------
BEGIN TRANSACTION
-- BEGING TRANSACTION
call of stored procedure -- ROLLBACK TRANASCTION
-- ROLLBACK TRANSACTION
ROLLBACK TRANSACTION
-----------------------------------------------------------
It can rollback only one time, it won't have multi rollback statements, also check the return statements which is causing the issue.
In nested procedures ROLLBACK should be used with care, detailed explanation here https://stackoverflow.com/a/74479802/6204480
i have a loop while in sql which do something as it
begin tran one
do some inserts in others tables
--start loop
begin tran two
--do something
begin try
--if something fail then a trigger does rollback and this return a error (and this goes to catch), then don't i need do the rollbak in catch? this could not be dissable because this is working on production
--something finished ok
commit tran two
end try
begin catch
rollback tran two
end catch
--finished loop
commit
----------
i got this error
Uncommittable transaction is detected at the end of the batch. The
transaction is rolled back.
begin tran one
begin tran two
rollback tran two
doing this code i get this:
Cannot roll back two. No transaction or savepoint of that name was found.
I only want the subquery to rollback the second loop and continue with others records.
Operator rollback rolls back all transaction, for roll back only second loop you you must use savepoints:
begin tran one
-- do some inserts in others tables
--start loop
save tran two -- begin tran two
--do something
begin try
update product set id = 1 --if something fail then a trigger does rollback and this return a error (and this goes to catch), then don't i need do the rollbak in catch? this could not be dissable because this is working on production
--something finished ok
commit tran two
end try
begin catch
rollback tran two
end catch
--finished loop
commit
trigger example:
create table product (id int)
GO
create trigger product_trigger on product for update
as
set xact_abort off
if (select count(*) from inserted i join product p on i.id=p.id)=0 begin
if (##trancount>0) begin
/* rollback */
raiserror('product does not exist', 16, 1)
end
end
In my case, was my code was calling, thru an EF DbContext method, a SQL Server stored procedure, which contained a non-nested transaction.
Since, as #NotMe has already pointed-out, that "there is no such as a nested transaction in SQL Server", I began wondering whether my process was really transaction-nestingless.
Suspecting, that my DbContext had some guilt, I started checking on DbContext options, until DbContext.Configuration.EnsureTransactionsForFunctionsAndCommands = True caught my attention.
So, as soon as I changed it value to True, everything worked successfully.
MyDbContext.Configuration.EnsureTransactionsForFunctionsAndCommands = false;
What happened?
Well, in my opinion, EF's ObjectContext.ExecuteFunction method was managing its own outer transaction as a wrapper to my stored procedure's inner transaction, so, when my stored procedure's ROLLBACK TRAN was hit, there was no pending transaction when EF's COMMIT/ROLLBACK code was hit.
Oddly enough, while gathering some references on EnsureTransactionsForFunctionsAndCommands property, I found that this default behaviour is due to one of the worst (in my opinion) EF team's decision ever, since it collides diretly with every ROLLBACK TRAN inside a T-SQL script.
For further details on EF, check insightfull SO's QA at EF6 wraps every single stored procedure call in its own transaction. How to prevent this?
Basically, everyone should check ##trancount > 0 before issuing a ROLLBACK command, whether named or not, specially inside stored procedure.
CREATE PROCEDURE Proc1 AS
BEGIN
BEGIN TRAN
EXEC Proc2
IF(##trancount > 0)
COMMIT TRAN
END
CREATE PROCEDURE Proc2 AS
BEGIN
BEGIN TRAN
ROLLBACK TRAN
END
For better awareness about Microsoft SQL Server's nested transactions, I would suggest reading the following article
Be careful using ROLLBACK on nested transaction in SQL Server!
Hope it helps someone :-)
I would like to start a transaction through a sql procedure, run other 2 procedure, and then run the first procedure with command: 'commit'.
Do you believe that this could be possible? I tried but received an error.
Transaction count after EXECUTE indicates a mismatching number of BEGIN and COMMIT statements. Previous count = 0, current count = 1.
This happens because SQL Server does not really support nested transactions.
If you commit or rollback in a nested stored proc (not transaction), then you'll generate error 266 because of a ##TRANCOUNT mismatch on start and entry.
You should pair up your BEGIN TRAN and COMMITs in the same SPROC.
If there is no concept of nested transaction then you need to do rollback/commit in same sproc. You can use SET XACT_ABORT ON suppresses error 266 caused by mismatched ##TRANCOUNT.
not sure about nested transactions in sql server
but you can try this one
Begin Try
Begin Transaction1
Call Proc1
Call Proc2
Call Proc3
Commit
End Transaction
Catch
Rollback
I want to build a T-SQL change script that rolls out database changes from dev to test to production.
I've split the script into three parts:
DDL statements
changes for stored procedures (create and alter procedure)
data creation and modification
I want all of the changes in those three scripts to be made in a transaction. Either all changes in the script are processed or - upon an error - all changes are rolled back.
I managed to do this for the steps 1 and 3 by using the try/catch and begin transaction statements.
My problem is now to do the same thing for the stored procedures.
A call to "begin transaction" directly before a "create stored procedure" statement results in a syntax error telling me that "alter/create procedure statement must be the first statement inside a query batch".
So I wonder how I could combine multiple create/alter procedure statements in one transaction.
Any help is highly appreciated ;-)
Thanks
You can use dynamic SQL to create your stored procedures.
EXEC ('CREATE PROC dbo.foo AS ....`)
This will avoid the error "alter/create procedure statement must be the first statement inside a query batch"
Try this:
begin transaction
go
create procedure foo as begin select 1 end
go
commit transaction
try putting the steps in a job
BEGIN TRANSACTION
BEGIN TRY
-- Do your stuff here
COMMIT TRANSACTION
PRINT 'Successfull.'
END TRY
BEGIN CATCH
SELECT
ERROR_NUMBER() as ErrorNumber,
ERROR_MESSAGE() as ErrorMessage;
ROLLBACK TRANSACTION
END CATCH