Re: BUG #15344: pg_proc.proisagg was removed incompatibly in PostgreSQL 11

On Tue, Aug 21, 2018 at 4:28 PM Andres Freund <andres@anarazel.de> wrote:

> Hi,
>
> On 2018-08-21 14:23:45 +0000, PG Bug reporting form wrote:
> > When comparing the current version (10) [1] and the developer version
> (11)
> > [2] of the pg_proc documentation, then it can be seen that the
> > pg_proc.proisagg column was removed backwards incompatibly. The
> > documentation states for [1]:
>
> Please note that the pg_catalog.* tables (and views) are *NOT* intended
> to backwards compatible between major versions. We change them in ways
> backward incompatible all the time.
>

The pg_catalog tables do seem to be the only way to reverse engineer some
more sophisticated things in the database. I imagine that this is being
done by tool vendors like myself (jOOQ) quite a bit. And there are tons of
Stack Overflow answers that show how to query the pg_catalog tables, all of
them risking to be outdated between major versions. These queries are
probably used by quite a few people in some home grown build tool, reverse
engineering tool, etc.

I understand that backwards compatibility is quite a bit of extra work, but
in cases like this particular one, the price to pay seems relatively low.
Perhaps a new strategy could be to break things only if there is really no
other solution?

Thanks,
Lukas