How to trace T-SQL function calls

Question

I'm trying to debug a rather complicated formula evaluator written in T-SQL UDFs (don't ask) that recursively (but indirectly through an intermediate function) calls itself, blah, blah.

And, of course, we have a bug.

Now, using PRINT statements (that can then be read from ADO.NET by implementing a handler for the InfoMessage event), I can simulate a trace for stored procedures.

Doing the same for UDF results in a compile time message:

Invalid use of side-effecting or time-dependent operator in 'PRINT' within a function.

I get the message (PRINT does some stuff like resetting @@ROWCOUNT which definitly is a no-no in UDFs, but how can I trace through the calls? I want to have this trace printed out, so I can study it without getting distracted by stepping through the calls in the debugger...

EDIT: I have tried to use the SQL Profiler (this was a first time one for me), but I can't figure out what to trace for: Although I can get the trace to output the queries sent to the database, they are opaque in the sense that I can't drill down to the Expression-UDFs called: I can trace the actual Stored Procedure invoked, but the UDFs called by this procedure are not listed. Am I missing something? I guess not...

EDIT #2: Allthough the (auto-)accepted answer does trace the function calls - very helpful, thanks - it does not help in finding out what parameters were passed to the function. This, of course, is essential in debugging recursive functions. I will post if I find any sollution at all...

Answer 1

Why not use SQL Profiler with statement level events added?

Edit: Add events for Stored Procedures : SP:Stmt Starting or SP:Stmt Completed Use variables to debug if needed, i.e. set @debug='i am here'; UDF's, while not technically stored procedures, will get traced with the statement level events.

Answer 2

In the SQL profiler, you need: SP:Starting, SP:StmtStarting, SP:Completed, SQL:BatchStarting. Then, you get every entry, exit from the functions/stored procedures.

alter FUNCTION [dbo].[ufn_mjf](@i numeric(10))
    RETURNS numeric(20) 
AS
BEGIN
declare @datapoint varchar(10)

    set @datapoint = 'hello world'

    return @i
END
go
drop table foo
go
create table dbo.foo ( foo_id numeric(10)) 
go
delete from foo
insert into foo ( foo_id ) values ( 1 )
insert into foo ( foo_id ) values ( 2 )

select foo_id, dbo.ufn_mjf(foo_id) from foo

with this, I get:

SQL:BatchStarting   alter FUNCTION [dbo].[ufn_mjf](@i numeric(10))
SQL:BatchStarting   drop table foo
SQL:BatchStarting   create table dbo.foo ( foo_id numeric(10)) 
SQL:BatchStarting   delete from foo
    insert into foo ( foo_id ) values ( 1 )
    insert into foo ( foo_id ) values ( 2 )
    select foo_id, dbo.ufn_mjf(foo_id) from foo
SP:Starting select foo_id, dbo.ufn_mjf(foo_id) from foo
SP:StmtStarting set @datapoint = 'hello world'
SP:StmtStarting return @i
SP:Completed    select foo_id, dbo.ufn_mjf(foo_id) from foo
SP:Starting select foo_id, dbo.ufn_mjf(foo_id) from foo
SP:StmtStarting set @datapoint = 'hello world'
SP:StmtStarting return @i
SP:Completed    select foo_id, dbo.ufn_mjf(foo_id) from foo

is that enough for you?

Answer 3

This looks like what you need but it's only available in team/pro versions of Visual Studio.