Re: Let's remove DSM_INPL_NONE.

On 2018-02-27 14:41:47 -0500, Tom Lane wrote:
> Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> > On Thu, Feb 15, 2018 at 1:00 PM, Andres Freund <andres(at)anarazel(dot)de> wrote:
> >> Hm, I'm not quite convinced by this. Seems to make testing a bunch of
> >> codepaths harder. I think it's fine to say that pg doesn't work
> >> correctly with them disabled though.
>
> > I'm not sure I understand this. Do you mean we should just add a
> > disclaimer to the documentation?
>
> What I didn't understand about it was what kind of testing this'd make
> harder. If we desupport dynamic_shared_memory_type=none, there aren't
> any code paths that need to cope with the case, and we should just
> remove any code that thereby becomes unreachable.

What I'm concerned about isn't so much testing paths specific to
dynamic_shared_memory_type=none, but paths where we currently need
fallbacks for the case we couldn't actually allocate dynamic shared
memory. Which I think we at least somewhat gracefully need to deal with.

Greetings,

Andres Freund