Re: Fix comments related to pending statistics

Hi,

On Thu, Dec 12, 2024 at 09:20:15AM +0900, Michael Paquier wrote:
> On Wed, Dec 11, 2024 at 07:32:38AM +0000, Bertrand Drouvot wrote:
> > On Wed, Dec 11, 2024 at 02:56:08PM +0900, Michael Paquier wrote:
> >> Your suggestion does not look completely right to me. There is
> >> nothing preventing us from using something else than event counters
> >> since we don't use memcpy() and there is no comparison work, no? It
> >> seems to me that we could remove the entire sentence instead.
> >
> > Do you mean also remove the comments in pgstat_function_flush_cb() and
> > pgstat_subscription_flush_cb()? Those comments look fine to me given
> > the places where those pending entries are created meaning in
> > pgstat_init_function_usage() for the functions and pgstat_report_subscription_error()
> > and pgstat_report_subscription_conflict() for the subscriptions.
>
> My apologies for the confusion. I see no problem with the existing
> comments in pgstat_subscription_flush_cb() and
> pgstat_function_flush_cb() because they still apply.

got it, thanks for the clarification.

> The only thing we should do here is to remove the comment for
> PgStat_FunctionCounts because we could add pointers or something else
> than plain counters in this structure,

I see what you mean and you are right (I misread the initial comment so updated
it wrongly). Removed in v2 attached.

> and fix the comment of
> PgStat_TableCounts in the lines of what you are suggesting.

Yeap. I also just realized that the same kind of comments are missing for
PgStat_BgWriterStats and PgStat_CheckpointerStats (for which we make use
of pg_memory_is_all_zeros() to detect whether there are any stats updates to
apply). Adding those in passing.

Regards,

--
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com