Re: Cache lookup errors with functions manipulation object addresses

On 2018-Dec-13, Michael Paquier wrote:

> > I support 0001 other than those two points.
> 
> Attached is an updated version for that as 0001.  Thanks for the
> review.  Does that part look good to you now?

+1.

> > +SELECT * FROM pg_identify_object_as_address('pg_proc'::regclass, 0, 0); -- no function
> > + type | object_names | object_args 
> > +------+--------------+-------------
> > +      | {}           | {}
> > +(1 row)
> > 
> > All the other cases you add have a non-empty value in "type".
> 
> On this one I would expect NULL for object_names and object_args, as
> empty does not make sense for an undefined object, still "type" should
> print...  "type".

Hmm ... "routine"?

I'm not sure if NULLs are better than empty arrays, but I agree that we
should pick one representation for undefined object and use it
consistently for all object types.

> > I think this is our chance to fix the mess.  Previously (before I added
> > the SQL-access of the object addressing mechanism in 9.5 I mean) it
> > wasn't possible to get at this code at all with arbitrary input, so this
> > is all a "new" problem (I mean new in the last 5 years).

Obviously I failed to subtract 11 from 9.5 correctly ... I meant 4
years.


> This requires a bit more work with the low-level APIs grabbing the
> printed information though.  And I think that the following guidelines
> make sense to work on as a base definition for undefined objects:
> - pg_identify_object returns the object type name, NULL for the other fields.
> - pg_describe_object returns just NULL.
> - pg_identify_object_as_address returns the object type name and NULL
> for the other fields.

Sounds good to me.

> There is some more refactoring work still needed for constraints, large
> objects and functions, in a way similar to a26116c6.  I am pretty happy
> with the shape of 0001, so this could be applied, 0002 still needs to be
> reworked so as all undefined object types behave as described above in a
> consistent manner.  Do those definitions make sense?

I think so, yes.

Thanks for taking care of this.

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
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