Re: No longer possible to query catalogs for index capabilities?

Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> On Mon, Jul 25, 2016 at 10:35 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> You missed the "compelling argument why it's needed" part. What is the
>> need for this?

> It's self-evident that this thread wouldn't exist if it were not the
> case that people had queries that no longer work because of these new
> changes. You can hold your breath and pretend that every single one
> of those queries is probably misdesigned, but I do not think anyone
> else will find that argument convincing.

We've already broken existing queries against pg_am, simply because the
columns are not there anymore; and that decision is not getting undone
at this point. I'm willing to consider putting back some substitute
capability, but I'd like to see as much evidence for adding that as we'd
expect for any other new feature. Andrew still hasn't shown a concrete
example of what he needs to do and why.

regards, tom lane