Re: WAL usage calculation patch - Mailing list pgsql-hackers

From Amit Kapila
Subject Re: WAL usage calculation patch
Date
Msg-id CAA4eK1+dhq1hdJo+tmf0CyDBhWV1H0dTWbEDio-cMk=10BDtTA@mail.gmail.com
Whole thread Raw
In response to Re: WAL usage calculation patch  (Dilip Kumar <dilipbalaut@gmail.com>)
Responses Re: WAL usage calculation patch  (Kyotaro Horiguchi <horikyota.ntt@gmail.com>)
Re: WAL usage calculation patch  (Amit Kapila <amit.kapila16@gmail.com>)
List pgsql-hackers
On Thu, Apr 2, 2020 at 8:06 PM Dilip Kumar <dilipbalaut@gmail.com> wrote:
>
> On Thu, Apr 2, 2020 at 6:41 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> >
> > 4.
> > /* # of WAL full page image generated */
> > Can we change it to "/* # of WAL full page image records generated */"?
>
> IMHO, "# of WAL full-page image records" seems like the number of wal
> record which contains the full-page image.
>

I think this resembles what you have written here.

>  But, actually, this is the
> total number of the full-page images, not the number of records that
> have a full-page image.
>

We count this when forming WAL records.  As per my understanding, all
three counters are about WAL records.  This counter tells how many
records have full page images and one of the purposes of having this
counter is to check what percentage of records contain full page
image.

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



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