Re: Assertions in PL/PgSQL

Hello

2013/9/18 Marko Tiikkaja <marko(at)joh(dot)to>

> On 2013-09-16 21:24, Pavel Stehule wrote:
>
>> 2. a failed assert should to raise a exception, that should not be handled
>> by any exception handler - similar to ERRCODE_QUERY_CANCELED - see
>> exception_matches_conditions.
>>
>
> I'm not sure what I think about that idea. I see decent arguments for it
> working either way. Care to unravel yours a bit more?
>

yes

so

CREATE OR REPLACE FUNCTION foo(a int) RETURNS int
BEGIN
ASSERT a BETWEEN 1 AND 100;
RETURNS a;
END;
$$ LANGUAGE plpgsql;

CREATE OR REPLACE FUNCTION proc()
RETURNS int AS $$
BEGIN
do some complex logic that exec a foo function

EXCEPTION WHEN OTHERS THEN
-- log some errors
INSERT INTO log VALUES(...)
END;
$$ LANGUAGE plpgsql;

In this code a assert fail can be lost in app log. Or can be knowingly
handled and ignored - what is wrong, and should not be allowed.

When I wrote a little bit complex procedures, I had to use a EXCEPTION WHEN
OTHERS clause - because I would not to lost a transaction. It worked, but
searching a syntax errors was significantly harder - so on base of this
experience I am thinking so some errors can be handled (related to database
usage) and others not - like syntax errors in PL/pgSQL or possible
assertions (although we can handle syntax error, but I don't think so it is
practical). It significantly increase a work that is necessary for error
identification.

Regards

Pavel

>
>
> Regards,
> Marko Tiikkaja
>