Re: Fix data checksum progress reporting docs

> On 10 Jul 2026, at 15:29, Fujii Masao <masao(dot)fujii(at)gmail(dot)com> wrote:
>
> Thanks for updating the patch!

Thanks for review, and apologies for the delay in getting back to this.

> On Fri, Jul 10, 2026 at 7:00 PM Daniel Gustafsson <daniel(at)yesql(dot)se> wrote:
>>> Shouldn't "the process which operate" be either "the process which operates"
>>> or "the processes which operate"? Since multiple data checksums workers
>>> can run, the latter seems more appropriate.
>>
>> Currently the processing is limited to a single worker, so I think the proposed
>> wording is more appropriate.
>
> So "operate" of "the process which operate" should be "operates"
> (i.e., "s" is necessary for "operate")?

Fixed.

>>> While looking at the related code, I also found that
>>> B_DATACHECKSUMSWORKER_LAUNCHER and B_DATACHECKSUMSWORKER_WORKER
>>> were added as BackendType entries in miscadmin.h. Since those entries appear
>>> under the comment for auxiliary processes, it could give the impression that
>>> the data checksums launcher and workers are auxiliary processes. To avoid
>>> that confusion, would it make sense to add a comment such as:
>>>
>>> -------------------------
>>> B_WAL_WRITER,
>>>
>>> + /*
>>> + * XXXXXXXXXX
>>> + */
>>> B_DATACHECKSUMSWORKER_LAUNCHER,
>>> B_DATACHECKSUMSWORKER_WORKER,
>>> -------------------------
>>
>> Fair point, see attached.
>
> + /* Background worker processes */
>
> Thanks for adding the comment! I'm a bit concerned that it's misleading,
> since enum BackendType already contains background worker entries
> such as B_BG_WORKER and B_SLOTSYNC_WORKER. So, how about making it
> more specific? For example:
>
> ------------
> Data checksums processes are dynamic background workers, but they
> use dedicated backend types for pgstat I/O accounting.
> ------------

I like that version, added in the attached v3.

>>> BTW, I'm also wondering why dedicated BackendType entries were added for
>>> the data checksums processes, while other background workers don't have
>>> their own BackendType values.
>>
>> They are need for the pgstat system though aren't they, or am I missing
>> something?
>
> As I understand it, dedicated backend types are not inherently required
> by the pgstat infrastructure. They are needed here so that pg_stat_io
> can account for I/O performed by the data checksums launcher and
> workers separately from generic background workers. Otherwise,
> their I/O would simply be counted under the background worker backend
> type, making it impossible to distinguish their I/O statistics.
> Is this my understanding right??

Yes, your understanding matches mine, but I didn't explain it even close to as
well as you did.

--
Daniel Gustafsson