Re: Strange failure in LWLock on skink in REL9_5_STABLE

On Fri, Sep 21, 2018 at 4:43 PM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Thomas Munro <thomas(dot)munro(at)enterprisedb(dot)com> writes:
> > On Fri, Sep 21, 2018 at 4:06 PM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> >> Why would we fix it rather than just removing it?
>
> > I assumed we wouldn't remove an extern C function extension code
> > somewhere might use. Though admittedly I'd be surprised if anyone
> > used this one.
>
> Unless it looks practical to support this behavior in the Windows
> and SysV cases, I think we should get rid of it rather than expend
> effort on supporting it for just some platforms.

We can remove it in back-branches without breaking API compatibility:

1. Change dsm_impl_can_resize() to return false unconditionally (I
suppose client code is supposed to check this before using
dsm_resize(), though I'm not sure why it has an "impl" in its name if
it's part of the public interface of this module).
2. Change dsm_resize() and dsm_remap() to raise an error conditionally.
3. Rip out the DSM_OP_RESIZE cases from various places.

Then in master, remove all of those functions completely. However,
I'd feel like a bit of a vandal. Robert and Amit probably had plans
for that code...?

--
Thomas Munro
http://www.enterprisedb.com