Re: Detach shared memory in Postmaster child if not needed

On 29/07/2024 21:10, Robert Haas wrote:
> On Mon, Jul 29, 2024 at 5:57 AM Rui Zhao <xiyuan(dot)zr(at)alibaba-inc(dot)com> wrote:
>> Prior to PG16, postmaster children would manually detach from shared memory
>> if it was not needed. However, this behavior was removed in fork mode in
>> commit aafc05d.
>
> Oh. The commit message makes no mention of that. I wonder whether it
> was inadvertent.
>
>> Detaching shared memory when it is no longer needed is beneficial, as
>> postmaster children (like syslogger) don't wish to take any risk of
>> accidentally corrupting shared memory. Additionally, any panic in these
>> processes will not reset shared memory.
>
> +1.
>
>> The attached patch addresses this issue by detaching shared memory after
>> fork_process().
>
> I don't know whether this is the correct approach or not, but
> hopefully Heikki can comment.

Good catch, it was not intentional. The patch looks good to me, so
committed. Thanks Rui!

--
Heikki Linnakangas
Neon (https://neon.tech)