Re: Delete cascade with three levels bug ?

On Tue, Oct 27, 2009 at 10:41 AM, Euler Taveira de Oliveira
<euler(at)timbira(dot)com> wrote:
> Marcelo Costa escreveu:
>> Hi, hackers
>>
>> I have a problem at PostgreSQL 8.3.5 (Slackware Server and Win 2003
>> Server) SO independent.
>>
>> When run the scripts below I receive the error:
>>
> This is not a bug. There are many ways to shoot yourself in the foot; and it
> is one of them...
>
>> UPDATE pg_trigger SET tgdeferrable = TRUE, tginitdeferred = TRUE;
>>
> This query will defer all of the triggers, including the cascade ones. If you
> compiles with --enable-cassert you will see:
>
> TRAP: FailedAssertion("!(afterTriggers->query_depth >= 0)", Arquivo:
> "/a/pgsql/src/backend/commands/trigger.c", Linha: 3893)
>
> Why don't you use the syntax (DEFERRABLE and INITIALLY DEFERRED)? That will do
> the Right Thing (TM).
>
> BTW, is it worth preventing such a crash putting an elog message in trigger.c?

It doesn't seem right to allow a catalog change that results in an
assertion failure. Seems like we should either prevent the catalog
change, or have an elog() there rather than Assert().

...Robert