Re: Inconsistency in startup process's MyBackendId and procsignal array registration with ProcSignalInit()

On Tue, Oct 12, 2021 at 2:03 PM Kyotaro Horiguchi
<horikyota.ntt@gmail.com> wrote:
> > [1] -
https://www.postgresql.org/message-id/CALj2ACXZ_o7rcOb7-Rs96P0d%3DEi%2Bnvf_WZ-Meky7Vv%2BnQNFYjQ%40mail.gmail.com
>
> The patch does this:
>
>                 case StartupProcess:
> +                       MyBackendId = MaxBackends + MyAuxProcType + 1;
>
> as well as this:
>
> +       shmInvalBuffer->maxBackends = MaxBackends + 1;
>
> These don't seem to be in the strict correspondence.  I'd prefer
> something like the following.
>
> +   /* currently only StartupProcess uses nailed SI slot */
> +       shmInvalBuffer->maxBackends = MaxBackends + StartupProcess + 1;

I don't think it is a good idea to use macro StartupProcess (because
the macro might get changed to a different value later). What we
essentially need to do for procState array is to extend its size by 1
(for startup process) which is being handled separately in [1]. Once
the patch at [1] gets in, the patch proposed here will not have the
above change at all.

[1] -
https://www.postgresql.org/message-id/CALj2ACXZ_o7rcOb7-Rs96P0d%3DEi%2Bnvf_WZ-Meky7Vv%2BnQNFYjQ%40mail.gmail.com

Regards,
Bharath Rupireddy.