Re: Determine the name of the calling function

Hello, Tom,

I found the problem. I was doing just about the same thing as you, except
I was passing the value of "t" up the stack as a return value from the sub-
and calling functions. When I looked in the pgadmin log, I saw what you
were seeing. It looks like "t" has LFs or CRs embedded in the text and I
was getting just "line 1", which was the "PL/pgSQL function f1() line 5 at
assignment" part. The part I wanted was in line 2.

The output from PG_EXCEPTION_CONTEXT looks parseable, with line 1
containing the current function, and line 2, the calling function. The
lines are variable length but the LF or CR should be identifiable. Add in
the fact of the variable number of lines you got from
PG_EXCEPTION_CONTEXT--where line 1 become 2, and line 2 becomes 3--and the
project is a pain but doable.

Thank you for your help. I don't think I would have figured this out on my
own, at least not for quite a while.

Sincerely, Jack

On Fri, Jan 18, 2013 at 3:09 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> Jack Kaufman <jack(dot)kaufman(at)sanmina(dot)com> writes:
> > By the way, PG_EXCEPTION_CONTEXT provided only the (currently executing)
> > API function name and line number of the exception (where I caused a
> > divide-by-zero). No function-call stack. :( But thanks, anyway.
>
> Really? I tried this:
>
> create function f1() returns int language plpgsql as $$
> declare x int; t text;
> begin
> begin
> x := 1/0;
> exception
> when division_by_zero then
> get stacked diagnostics t = pg_exception_context;
> raise notice '%', t;
> end;
> return 0;
> end
> $$;
>
> create function f2() returns int language plpgsql as $$
> begin
> return f1();
> end$$;
>
> and I get
>
> regression=# select f2();
> NOTICE: PL/pgSQL function f1() line 5 at assignment
> PL/pgSQL function f2() line 3 at RETURN
> CONTEXT: PL/pgSQL function f2() line 3 at RETURN
> f2
> ----
> 0
> (1 row)
>
> So the result of pg_exception_context clearly does contain the info you
> want. Pulling it out is left as an exercise for the reader ;-)
>
> Curiously, the behavior doesn't seem to be totally consistent --- when I
> run the same case again, I get an additional line of context:
>
> regression=# select f2();
> NOTICE: SQL statement "SELECT 1/0"
> PL/pgSQL function f1() line 5 at assignment
> PL/pgSQL function f2() line 3 at RETURN
> CONTEXT: PL/pgSQL function f2() line 3 at RETURN
> f2
> ----
> 0
> (1 row)
>
> That seems like a bug ...
>
> regards, tom lane
>

--
Jack Kaufman
MDS Application Devl (US)
Sanmina-SCI Corporation - Owego site
Email: jack(dot)kaufman(at)sanmina(dot)com
Skype: jack_kaufman_sanm
607-723-0507

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