Re: User Interface for WAL usage data

On Thu, Apr 2, 2020 at 11:28 AM Kyotaro Horiguchi
<horikyota.ntt@gmail.com> wrote:
>
> At Thu, 2 Apr 2020 00:41:20 -0500, Justin Pryzby <pryzby@telsasoft.com> wrote in
> > On Thu, Apr 02, 2020 at 10:13:18AM +0530, Amit Kapila wrote:
> > > In thread [1], we are discussing to expose WAL usage data for each
> > > statement in a way quite similar to how we expose BufferUsage data.
> > > The way it exposes seems reasonable to me and no one else raises any
> > > objection.  It could be that it appears fine to others who have
> > > reviewed the patch but I thought it would be a good idea to write a
> > > separate email just for its UI and see if anybody has objection.
> >
> > +1
> >
> > Regarding v10-0004-Add-option-to-report-WAL-usage-in-EXPLAIN-and-au.patch:
> > I think there should be additional spaces before "full" and before "bytes":
> >
> > >    WAL: records=2359 full page records=42 bytes=447788
> >
> > Compare with these:
> >
> >        "Sort Method: %s  %s: %ldkB\n",
> >        "Buckets: %d (originally %d)  Batches: %d (originally %d)  Memory Usage: %ldkB\n",
> >        "Buckets: %d  Batches: %d  Memory Usage: %ldkB\n",
> >
> > Otherwise "records=2359 full page records=42" is hard to parse.
>
> I got the same feeling seeing the line.
>

But isn't this same as we have BufferUsage data?  We can probably
display it as full_page_writes or something like that.

> "full page records" seems to be showing the number of full page
> images, not the record having full page images.
>

I am not sure what exactly is a difference but it is the records
having full page images.  Julien correct me if I am wrong.

-- 
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com