Re: Considering signal handling in plpython again

On 16 May 2018 16:50:24 EEST, Hubert Zhang <hzhang(at)pivotal(dot)io> wrote:
>There are remaining two problems
>
>1. Do we need to consider when to delete the extension hook or it's not
>necessary?

No, PostgreSQL never unloads shared libraries, so that can be ignored.

We used to, and that's what _PG_fini() was for. But we stopped doing that, because it was unsafe. IIRC, hook functions like this was exactly the reason that made it unsafe.

>2. Do we need to use explicit hook list(List *cancel_hook_list) instead
>of
>implicit cancel_hook(which relies on the extension to link the
>cancel_hook
>inside their code
> e.g. prev_hook = cancel_hook; cancel_hook=my_hook; void
>my_hook(){mywork(); (*prev_hook)();} )?
> I didn't find any explicit hook list in PG code base, is that a good
>practice

I didn't understand what you meant with a hook list. But I believe the way I had the hook in the patch was fine.

- Heikki