Re: Bogus collation version recording in recordMultipleDependencies

On Mon, Apr 19, 2021 at 10:53 AM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> I think that the real fundamental bug is supposing that static analysis
> can give 100% correct answers. Even if it did do so in a given state
> of the database, consider this counterexample:
>
> create type myrow as (f1 int, f2 int);
> create table mytable (id bigint, r1 myrow, r2 myrow);
> create index myindex on mytable(id) where r1 < r2;
> alter type myrow add attribute f3 text;
>
> myindex is recorded as having no collation dependency, but that is
> now wrong.

Is it really the case that static analysis of the kind that you'd need
to make this 100% robust is fundamentally impossible? I find that
proposition hard to believe.

I'm not sure that you were making a totally general statement, rather
than a statement about the patch/implementation, so perhaps I just
missed the point.

--
Peter Geoghegan