Re: About to add WAL write/fsync statistics to pg_stat_wal view

On 2021-01-27 00:14, David G. Johnston wrote:
> On Mon, Jan 25, 2021 at 11:56 PM Masahiro Ikeda
> <ikedamsh(at)oss(dot)nttdata(dot)com> wrote:
>
>>> (wal_write)
>>> The number of times WAL buffers were written out to disk via
>> XLogWrite
>>>
>>
>> Thanks.
>>
>> I thought it's better to omit "The" and "XLogWrite" because other
>> views'
>> description
>> omits "The" and there is no description of "XlogWrite" in the
>> documents.
>> What do you think?
>
> The documentation for WAL does get into the public API level of detail
> and doing so here makes what this measures crystal clear. The
> potential absence of sufficient detail elsewhere should be corrected
> instead of making this description more vague. Specifically, probably
> XLogWrite should be added to the WAL overview as part of this update
> and probably even have the descriptive section of the documentation
> note that the number of times that said function is executed is
> exposed as a counter in the wal statistics table - thus closing the
> loop.

Thanks for your comments.

I added the descriptions in documents and separated the patch
into attached two patches. First is to add wal i/o activity statistics.
Second is to make the wal receiver report the wal statistics.

Please let me know if you have any comments.

Regards,
--
Masahiro Ikeda
NTT DATA CORPORATION