Horton

Re: Bogus collation version recording in recordMultipleDependencies

Peter Geoghegan <pg@bowt.ie>

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From: Peter Geoghegan <pg@bowt.ie>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Andres Freund <andres@anarazel.de>, Julien Rouhaud <rjuju123@gmail.com>, Thomas Munro <thomas.munro@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2021-04-19T18:04:26Z
Lists: pgsql-hackers 
On Mon, Apr 19, 2021 at 10:53 AM Tom Lane <tgl@sss.pgh.pa.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

Commits

  1. Doc: Update notes about libc collation versions.

  2. Revert per-index collation version tracking feature.

  3. Rethink extraction of collation dependencies.

  4. Fix bogus collation-version-recording logic.

  5. Rename the "point is strictly above/below point" comparison operators.

  6. Move catalog toast table declarations