Re: ROWS vs RANGE in release notes for pg 16

Hi Erwin,

On 8/18/23 7:41 PM, Erwin Brandstetter wrote:
> The release notes for Postgres 16 says here:
> https://www.postgresql.org/docs/16/release-16.html#RELEASE-16-PERFORMANCE <https://www.postgresql.org/docs/16/release-16.html#RELEASE-16-PERFORMANCE>
>
> > Allow window functions to use ROWS mode internally when RANGE mode is
> specified but unnecessary (David Rowley)
>
> But the fix also applies to the much more common case where no mode has
> been specified, RANGE unfortunately being the default - including the
> most common use case "row_number() OVER (ORDER BY col)". This is what
> made me investigate, test and eventually propose a fix in the first
> place. See:
>
> https://www.postgresql.org/message-id/flat/CAGHENJ7LBBszxS%2BSkWWFVnBmOT2oVsBhDMB1DFrgerCeYa_DyA%40mail.gmail.com <https://www.postgresql.org/message-id/flat/CAGHENJ7LBBszxS%2BSkWWFVnBmOT2oVsBhDMB1DFrgerCeYa_DyA%40mail.gmail.com>
> https://www.postgresql.org/message-id/flat/CAApHDvohAKEtTXxq7Pc-ic2dKT8oZfbRKeEJP64M0B6%2BS88z%2BA%40mail.gmail.com <https://www.postgresql.org/message-id/flat/CAApHDvohAKEtTXxq7Pc-ic2dKT8oZfbRKeEJP64M0B6%2BS88z%2BA%40mail.gmail.com>
>
> Also, I was hoping to get a mention in the release note for working this
> out:
>
> > Allow window functions to use the faster ROWS mode internally when
> RANGE mode is specified or would be used by default, but unnecessary
> (David Rowley, Erwin Brandstetter)

Thanks for flagging. I suggest adding the comment to the release notes
thread on -hackers:

https://www.postgresql.org/message-id/flat/ZGaPa7M3gc2THeDJ%40momjian.us

Jonathan