Re: [HACKERS] Optional message to user when terminating/cancelling backend

> On 6 Jul 2018, at 02:18, Thomas Munro <thomas(dot)munro(at)enterprisedb(dot)com> wrote:
>
> On Fri, Jun 15, 2018 at 9:56 AM, Daniel Gustafsson <daniel(at)yesql(dot)se> wrote:
>> attached
>
> Hi Daniel,
>
> 6118 --select pg_cancel_backend(pg_backend_pid(), 'it brings on many changes');
> 6119 select pg_cancel_backend(pg_backend_pid(), NULL);
> 6120! ERROR: canceling statement due to user request
> 6121--- 25,32 ----
> 6122
> 6123 --select pg_cancel_backend(pg_backend_pid(), 'it brings on many changes');
> 6124 select pg_cancel_backend(pg_backend_pid(), NULL);
> 6125! pg_cancel_backend
> 6126! -------------------
> 6127! t
>
> Apparently Windows can take or leave it as it pleases.

Well played =)

> https://ci.appveyor.com/project/postgresql-cfbot/postgresql/build/1.0.4488

That reads to me like it’s cancelling another backend than the current one,
which clearly isn’t right as we’re passing pg_backend_pid(). I can’t really
see what Windows specific bug was introduced by this patch though (or well, the
bug exhibits itself on Windows but it may well be generic of course).

Will continue to hunt.

cheers ./daniel