Re: Weird failure with latches in curculio on v15

Hi,

On 2023-02-04 10:03:54 -0800, Nathan Bossart wrote:
> On Sat, Feb 04, 2023 at 03:30:29AM -0800, Andres Freund wrote:
> > That's kind of my problem with these changes. They try to introduce new
> > abstraction layers, but don't provide real abstraction, because they're
> > very tightly bound to the way the functions were called before the
> > refactoring. And none of these restrictions are actually documented.
>
> Okay. Michael, why don't we revert the shell_restore stuff for now? Once
> the archive modules interface changes and the fix for this
> SIGTERM-during-system() problem are in, I will work through this feedback
> and give recovery modules another try. I'm still hoping to have recovery
> modules ready in time for the v16 feature freeze.
>
> My intent was to improve this code by refactoring and reducing code
> duplication, but I seem to have missed the mark. I am sorry.

FWIW, I think the patches were going roughly the right direction, they
just needs a bit more work.

I don't think we should expose the proc_exit() hack, and its supporting
infrastructure, to the pluggable *_command logic. It's bad enough as-is,
but having to do this stuff within an extension module seems likely to
end badly. There's just way too much action-at-a-distance.

I think Thomas has been hacking on a interruptible system()
replacement. With that, a lot of this ugliness would be resolved.

Greetings,

Andres Freund