Question

So we have multiple stored procs that get used during a morning SQL job and the procs get called in sequence. In the event one of the queries inside a proc fails, we have an error catching/logging that we do for each query so we know exactly what piece failed. But the problem is that some of these processes are very difficult to start over if something failed so I am thinking of implementing a TRANSACTION in each stored proc.

The current procedure is similar to this:

CREATE PROCEDURE [dbo].[spStep01]
( 
    @Return_Message     Varchar(1024)   OUT     -- Error messages returned to the calling program
)
AS
BEGIN

SET NOCOUNT ON;

DECLARE @ErrorCode              int
DECLARE @ApplicationNumber      int             
DECLARE @TaskNumber             int             
DECLARE @TaskCompleted          smallint        
DECLARE @TaskFailed             smallint        
DECLARE @TaskRunning            smallint        
DECLARE @ErrorSeverity          smallint        
DECLARE @ErrorState             smallint        

SELECT @ErrorCode = @@ERROR
SELECT @ApplicationNumber   = 10                
SELECT @TaskNumber          = 1
SELECT @TaskCompleted       = 0
SELECT @TaskFailed          = -1
SELECT @TaskRunning         = 1
SELECT @ErrorSeverity       = 16
SELECT @ErrorState          = 1

/***************************************************************************
*  first insert
***************************************************************************/
    BEGIN TRY   
        INSERT INTO ...
    END TRY
    BEGIN CATCH
        SELECT @Return_Message = 'FAILED - first insert did not populate'
        EXEC dbo.spTrackTask '', @ApplicationNumber, @TaskNumber, @TaskFailed, @Return_Message      
        RAISERROR (@Return_Message, @ErrorSeverity, @ErrorState)
        RETURN 
    END CATCH

/***************************************************************************
*  second insert
***************************************************************************/
    BEGIN TRY   
        INSERT INTO ...
    END TRY
    BEGIN CATCH
        SELECT @Return_Message = 'FAILED -  second insert did not populate'
        EXEC dbo.spTrackTask '', @ApplicationNumber, @TaskNumber, @TaskFailed, @Return_Message      
        RAISERROR (@Return_Message, @ErrorSeverity, @ErrorState)
        RETURN 
    END CATCH


/***************************************************************************
* Procedure has completed successfully
***************************************************************************/
    SELECT @Return_Message = 'SUCCESS - Inserts were complete'
    EXEC dbo.spTrackTask '', @ApplicationNumber, @TaskNumber, @TaskCompleted, @Return_Message   


/*************************************
*  Get the Error Message for @@Error
*************************************/
    IF @ErrorCode <> 0
    BEGIN
        SELECT  @Return_Message = [Description]     -- Return the SQL Server error
          FROM  master.dbo.SYSMESSAGES
         WHERE  error = @ErrorCode
    END

/*************************************
*  Return from the Stored Procedure
*************************************/
    RETURN @ErrorCode                               -- =0 if success,  <>0 if failure

END

What I am trying to determine is if I wrap all of the TRY/CATCH blocks in a TRANSACTION and an error is raised if it will rollback everything. I looked around on SO and found a few examples of one TRY/CATCH block but we would have multiple in most of the stored procs. I don’t have much experience with transactions so I am not 100% sure how to implement it correctly in this case.

Will wrapping it in a TRANSACTION work? Or is there a better way to do this?

Answer 1

How about this

BEGIN TRANSACTION tx
BEGIN TRY
  @CurrentStep = "First Insert"
  INSERT ...

  @CurrentStep = "Second Insert"
  INSERT ...Second

  IF @@TRANCOUNT > 0
  BEGIN --SUCCESS, nothing failed, now I can commit!!
    SELECT @Return_Message = 'SUCCESS - Inserts were complete'
    EXEC dbo.spTrackTask '', @ApplicationNumber, @TaskNumber, @TaskCompleted, @Return_Message   
    COMMIT TRANSACTION tx;    -- now everything is committed
  END
END TRY

BEGIN CATCH 
  IF @@TRANCOUNT > 0 --something failed
  BEGIN
    IF @CurrentStep = 'First Insert'
      SELECT @Return_Message = 'FAILED - first insert did not populate'
    ELSE IF @CurrentStep = 'Second Insert'
      SELECT @Return_Message = 'FAILED - second insert did not populate'

    EXEC dbo.spTrackTask '', @ApplicationNumber, @TaskNumber, @TaskFailed, @Return_Message      
    RAISERROR (@Return_Message, @ErrorSeverity, @ErrorState)

    ROLLBACK TRAN tx; -- everything is rolled back
  END
END CATCH

Hope this does the trick for you, remember that everything inside a transaction should be committed or rolled back in one place, otherwise you’re better off having multiple transactions.