Re: [HACKERS] Custom compression methods

On Wed, Mar 17, 2021 at 02:50:34PM -0700, Andres Freund wrote:
> On 2021-03-17 16:01:58 -0400, Robert Haas wrote:
> > > - why is HIDE_TOAST_COMPRESSION useful? Doesn't quite seem to be
> > > comparable to HIDE_TABLEAM?
> >
> > Andres, what do you mean by this exactly? It's exactly the same issue:
> > without this, if you change the default compression method, every test
> > that uses \d+ breaks. If you want to be able to run the whole test
> > suite with either compression method and get the same results, you
> > need this. Now, maybe you don't, because perhaps that doesn't seem so
> > important with compression methods as with table AMs.

Arguably, it's more important, since it affects every column in \d+, not just a
"footer" line.

> I think that latter part is why I wasn't sure such an option is
> warranted. Given it's a builtin feature, I didn't really forsee a need
> to be able to run all the tests with a different compression method. And
> it looked a like it could just have been copied from the tableam logic,
> without a clear need. But if it's useful, then ...

This was one of my suggestions and contributions.
I copied it from tableam specifically, not incidentally.
https://www.postgresql.org/message-id/20210214184940.GL1793%40telsasoft.com

--
Justin