Re: pg_stat_progress_basebackup - progress reporting for pg_basebackup, in the server side

On 2020/02/18 16:02, Amit Langote wrote:
> On Mon, Feb 17, 2020 at 10:00 PM Fujii Masao
> <masao(dot)fujii(at)oss(dot)nttdata(dot)com> wrote:
>> On 2020/02/06 11:07, Amit Langote wrote:
>>> On Thu, Feb 6, 2020 at 9:51 AM Kyotaro Horiguchi <horikyota(dot)ntt(at)gmail(dot)com> wrote:
>>>> I thought of "establishing checkpoint" or "running a checkpoint" as
>>>> other candidates.
>>>
>>> Okay, I understand. I am fine with "running checkpoint", although I
>>> think "waiting for checkpoint" isn't totally wrong either.
>>
>> Yeah, but if "waiting for XXX" sounds a bit confusing to some people,
>> I'm OK to back to "waiting for XXX to finish" that you originally
>> proposed.
>>
>> Attached the updated version of the patch. This patch uses the following
>> descriptions of the phases.
>>
>> waiting for checkpoint to finish
>> estimating backup size
>> streaming database files
>> waiting for wal archiving to finish
>> transferring wal files
>
> Thanks for the new patch.

Thanks for reviewing the patch!

> I noticed that there is missing </para> tag in the documentation changes:

Could you tell me where I should add </para> tag?

> + <row>
> + <entry><literal>waiting for checkpoint to finish</literal></entry>
> + <entry>
> + The WAL sender process is currently performing
> + <function>pg_start_backup</function> to set up for
> + taking a base backup, and waiting for backup start
> + checkpoint to finish.
> + </entry>
> + <row>
>
> There should be a </row> between </entry> and <row> at the end of the
> hunk shown above.

Will fix. Thanks!

> Sorry for not saying it before, but the following text needs revisiting:

Of course, no problem. I'm happy to improve the patch!

> + <para>
> + Whenever <application>pg_basebackup</application> is taking a base
> + backup, the <structname>pg_stat_progress_basebackup</structname>
> + view will contain a row for each WAL sender process that is currently
> + running <command>BASE_BACKUP</command> replication command
> + and streaming the backup.
>
> I understand that you wrote "Whenever pg_basebackup is taking a
> backup...", because description of other views contains a similar
> starting line. But, it may not only be pg_basebackup that would be
> served by this view, no? It could be any tool that speaks Postgres'
> replication protocol and thus be able to send a BASE_BACKUP command.
> If that is correct, I would write something like "When an application
> is taking a backup" or some such without specific reference to
> pg_basebackup. Thoughts?

Yeah, there may be some such applications. But most users would
use pg_basebackup, so getting rid of the reference to pg_basebackup
would make the description a bit difficult-to-read. Also I can imagine
that an user of those backup applications would get to know
the progress reporting view from their documents. So I prefer
the existing one or something like "Whenever an application like
pg_basebackup ...". Thought?

Regards,

--
Fujii Masao
NTT DATA CORPORATION
Advanced Platform Technology Group
Research and Development Headquarters