Re: Assertions in PL/PgSQL

2013/9/23 Amit Khandekar <amit(dot)khandekar(at)enterprisedb(dot)com>

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> On 23 September 2013 10:10, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> wrote:
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>> 2013/9/22 Jaime Casanova <jaime(at)2ndquadrant(dot)com>
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>>>
>>> El 21/09/2013 17:16, "Jaime Casanova" <jaime(at)2ndquadrant(dot)com> escribió:
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>>> >
>>> > On Fri, Sep 20, 2013 at 5:17 AM, Marko Tiikkaja <marko(at)joh(dot)to> wrote:
>>> > > On 9/20/13 12:09 PM, Amit Khandekar wrote:
>>> > >>
>>> > >> On 16 September 2013 03:43, Marko Tiikkaja <marko(at)joh(dot)to> wrote:
>>> > >>>
>>> > >>> I think it would be extremely surprising if a command like that got
>>> > >>> optimized away based on a GUC, so I don't think that would be a
>>> good
>>> > >>> idea.
>>> > >>
>>> > >>
>>> > >>
>>> > >> In pl_gram.y, in the rule stmt_raise, determine that this RAISE is
>>> for
>>> > >> ASSERT, and then return NULL if
>>> plpgsql_curr_compile->enable_assertions is
>>> > >> false. Isn't this possible ?
>>> > >
>>> > >
>>> > > Of course it's possible. But I, as a PostgreSQL user writing
>>> PL/PgSQL code,
>>> > > would be extremely surprised if this new cool option to RAISE didn't
>>> work
>>> > > for some reason. If we use ASSERT the situation is different; most
>>> people
>>> > > will realize it's a new command and works differently from RAISE.
>>> > >
>>> > >
>>> >
>>> > What about just adding a clause WHEN to the RAISE statement and use
>>> > the level machinery (client_min_messages) to make it appear or not
>>> > of course, this has the disadvantage that an EXCEPTION level will
>>> > always happen... or you can make it a new loglevel that mean EXCEPTION
>>> > if asserts_enabled
>>> >
>>>
>>> meaning RAISE ASSERT of course
>>>
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>> After days I am thinking so it can be a good solution
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>> syntax - enhanced current RAISE
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>> RAISE ASSERT WHEN boolean expression
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>> RAISE ASSERT 'some message' WHEN expression
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>> and we can have a GUC that controls asserts per database - possibly
>> overwritten by plpgsql option - similar to current plpgsql options
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>> assert_level = [*ignore*, notice, warning, error]
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> The assert levels sound a bit like a user might be confused by these
> levels being present at both places: In the RAISE syntax itself, and the
> assert GUC level. But I like the syntax. How about keeping the ASSERT
> keyword optional ? When we have WHEN, we anyway mean that we ware asserting
> that this condition must be true. So something like this :
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> RAISE [ level ] 'format' [, expression [, ... ]] [ USING option =
> expression [, ... ] ];
> RAISE [ level ] condition_name [ USING option = expression [, ... ] ];
> RAISE [ level ] SQLSTATE 'sqlstate' [ USING option = expression [, ... ]
> ];
> RAISE [ level ] USING option = expression [, ... ];
> *RAISE [ ASSERT ] WHEN bool_expression;*
> RAISE ;
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I don't think so it is a good idea. WHEN clause should be independent on
exception level.

Pavel

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>> comments?
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>> Regards
>>
>> Pavel
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>> p.s. clause WHEN can be used for other exception level - so it can be a
>> interesting shortcut for other use cases.
>>
>> --
>>> Jaime Casanova
>>> 2ndQuadrant: Your PostgreSQL partner
>>>
>>
>>
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