Re: Why doesn't `RAISE EXCEPTION` provide error context?

Adding "raw" content present on Nabble that gets filtered by the mailing
list.

On Wednesday, April 1, 2015, Taytay <taylor(at)youneedabudget(dot)com> wrote:

> We make heavy use of `GET STACKED DIAGNOSTICS` to determine where errors
> happened.
> However, I am trying to use RAISE EXCEPTION to report errors, and have
> discovered that RAISE is specifically prevented from adding to the error
> context:

----
static void
plpgsql_exec_error_callback(void *arg)
{
PLpgSQL_execstate *estate = (PLpgSQL_execstate *) arg;

/* if we are doing RAISE, don't report its location */
if (estate->err_text == raise_skip_msg)
return;
----

>
> So that means that this doesn't work:
>
>
>
RAISE EXCEPTION 'This exception will not get a stack trace';

EXCEPTION WHEN others THEN

-- If the exception we're catching is one that Postgres threw,
-- like a divide by zero error, then this will get the full
-- stack trace of the place where the exception was thrown.
-- However, since we are catching an exception we raised manually
-- using RAISE EXCEPTION, there is no context/stack trace!
GET STACKED DIAGNOSTICS v_error_stack = PG_EXCEPTION_CONTEXT;

> I've posted more details here:
>
> http://dba.stackexchange.com/questions/96743/postgres-how-to-get-stack-trace-for-a-manually-raised-exception
>
> That context would be awfully useful for us, even for manually generated
> exceptions.
> Can anyone shed some light on A) why this is, and B) if it's still desired,
> and C) if so, are there any workarounds? Is there an exception I can trick
> Postgres into throwing that will include my user-generated string?
>
> Many thanks for any help you can offer.
>
>