How to rollback transaction in a stored procedure? - sql-server

Question

When the internal SP tries to rollback transaction it completed with an error:
Msg 266, Level 16, State 2, Procedure ptest, Line 0 [Batch Start Line
37] Transaction count after EXECUTE indicates a mismatching number of
BEGIN and COMMIT statements. Previous count = 1, current count = 0.
Is it possible to rollback transaction inside the internal SP?
IF NOT EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo].[ptest]') AND type in (N'P', N'PC'))
BEGIN
EXEC dbo.sp_executesql #statement = N'CREATE PROCEDURE [dbo].[ptest] AS'
END
GRANT EXECUTE on [dbo].[ptest] to public;
GO
ALTER PROCEDURE [dbo].[ptest]
#parrollback bit = 0
AS
BEGIN
SET NOCOUNT ON
SET XACT_ABORT OFF
select ##TRANCOUNT as '##TRANCOUNT:[ptest] '
if #parrollback is not null and #parrollback>0
if ##TRANCOUNT>0 rollback tran;
END
GO
IF NOT EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo].[pcaller]') AND type in (N'P', N'PC'))
BEGIN
EXEC dbo.sp_executesql #statement = N'CREATE PROCEDURE [dbo].[pcaller] AS'
END
GRANT EXECUTE on [dbo].[pcaller] to public;
GO
ALTER PROCEDURE [dbo].[pcaller]
AS
BEGIN
SET NOCOUNT ON
begin tran
select ##TRANCOUNT as '##TRANCOUNT: before [ptest]'
exec ptest 1
select ##TRANCOUNT as '##TRANCOUNT: after [ptest] '
if ##TRANCOUNT>0 rollback tran;
END
GO
-------------
exec pcaller
/*
IF EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo].[ptest]') AND type in (N'P', N'PC'))
drop proc pcaller
IF EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo].[ptest]') AND type in (N'P', N'PC'))
drop proc ptest
*/

Answer 1

try not to handle parent transactions inside a child procedure (exception when XACT_STATE() = -1). Handle the transaction at the "execution" level that started it.
if a procedure is executed in a parent transaction, then create a savepoint and rollback to it when needed. capture the execution result of the child procedure and handle the transaction at the parent level (if the parent is the one that begun the transaction).
CREATE OR ALTER PROCEDURE [dbo].[ptest] #parrollback bit = 0
AS
BEGIN
SET NOCOUNT ON
SET XACT_ABORT OFF
DECLARE #trancount INT = ##TRANCOUNT;
IF #trancount = 0
BEGIN
BEGIN TRANSACTION;
END
ELSE
BEGIN
SAVE TRANSACTION MySavepoint;
END
--do stuff.........
--when it is time to commit or check for errors
--assume #parrollback is the main control criterium
IF #parrollback = 1
BEGIN
IF #trancount = 0
BEGIN
ROLLBACK TRANSACTION;
RETURN(0);
END
ELSE
BEGIN
ROLLBACK TRANSACTION MySavePoint
RETURN (1);
END
END
--just handle #parrollback <> 1, for completeness of the test
IF #trancount = 0
BEGIN
COMMIT TRANSACTION;
END
RETURN (0);
END
GO
CREATE OR ALTER PROCEDURE dbo.pcaller
AS
BEGIN
SET NOCOUNT ON
DECLARE #ptestexec INT;
BEGIN TRANSACTION
select ##TRANCOUNT as '##TRANCOUNT: before [ptest]'
EXEC #ptestexec = dbo.ptest #parrollback = 1;
IF #ptestexec = 1
BEGIN
ROLLBACK TRANSACTION
END
ELSE
BEGIN
COMMIT TRANSACTION
END
--execute ptest, outside of a transaction
EXEC #ptestexec = dbo.ptest #parrollback = 0;
SELECT ##TRANCOUNT AS trancount1;
EXEC #ptestexec = dbo.ptest #parrollback = 1;
SELECT ##TRANCOUNT AS trancount2;
--execute ptest, outside of a transaction
BEGIN TRANSACTION;
--ptest executed in a parent transaction
EXEC #ptestexec = dbo.ptest #parrollback = 0;
SELECT ##TRANCOUNT AS trancount3; --ptest does not affect the parent transactions
COMMIT TRANSACTION --or rollback
END
GO
EXEC dbo.pcaller
GO