Re: Schema variables - new implementation for Postgres 15 (typo)

st 11. 1. 2023 v 10:08 odesílatel Julien Rouhaud <rjuju123(at)gmail(dot)com>
napsal:

> On Tue, Jan 10, 2023 at 08:35:16PM +0100, Pavel Stehule wrote:
> > út 10. 1. 2023 v 3:20 odesílatel Julien Rouhaud <rjuju123(at)gmail(dot)com>
> napsal:
> > >
> > > Another new behavior I see is the new rowtype_only parameter for
> > > LookupVariable. Has this been discussed?
> > >
> >
> > I think so it was discussed about table shadowing
> >
> > without this filter, I lost the message "missing FROM-clause entry for
> ..."
> >
> > -- should fail
> > SELECT varx.xxx;
> > -ERROR: missing FROM-clause entry for table "varx"
> > -LINE 1: SELECT varx.xxx;
> > - ^
> > +ERROR: type text is not composite
> > -- don't allow multi column query
> > CREATE TYPE vartesttp AS (a1 int, b1 int, c1 int);
> > CREATE VARIABLE v1 AS vartesttp;
> > @@ -1421,9 +1419,7 @@
> > DROP TYPE ab;
> > CREATE VARIABLE myvar AS int;
> > SELECT myvar.blabla;
> > -ERROR: missing FROM-clause entry for table "myvar"
> > -LINE 1: SELECT myvar.blabla;
> > - ^
> > +ERROR: type integer is not composite
> > DROP VARIABLE myvar;
> > -- the result of view should be same in parallel mode too
> > CREATE VARIABLE v1 AS int;
> >
> > My original idea was to try to reduce possible conflicts (in old versions
> > of this path, a conflict was disallowed). But it is true, so these "new"
> > error messages are sensible too, and with eliminating rowtype_only I can
> > reduce code.
>
> Ok! Another problem is that the error message as-is is highly unhelpful as
> it's not clear at all that the problem is coming from an unsuitable
> variable.
> Maybe change makeParamSessionVariable to use
> lookup_rowtype_tupdesc_noerror()
> and emit a friendlier error message? Something like
>
> variable "X.Y" is of type Z, which is not composite
>

done

>
> > I modified the IdentifyVariable function a little bit. With new argument
> > noerror I am able to ensure so no error will be raised when this function
> > is called just for shadowing detection.
>
> I locally modified IdentifyVariable to emit WARNING reports when noerror
> is set
> to quickly see how it was used and didn't get any regression test error.
> This
> definitely needs to be covered by regression tests. Looking as
> session_variables.sql, the session_variables_ambiguity_warning GUC doesn't
> have
> a lot of tests in general.
>

I enhanced regress tests about this scenario

Regards

Pavel