On Tue, 22 Aug 2023 at 10:08, Bruce Momjian <br...@momjian.us> wrote: > > On Sat, Aug 19, 2023 at 04:24:48AM +0200, Erwin Brandstetter wrote: > > I posted to pgsql-docs first, but was kindly redirected here by Jonathan: > > > > The release notes for Postgres 16 says here: > > https://www.postgresql.org/docs/16/release-16.html#RELEASE-16-PERFORMANCE > > > > Same as here: > > https://momjian.us/pgsql_docs/release-16.html#RELEASE-16-PERFORMANCE > > > > Allow window functions to use ROWS mode internally when RANGE mode is > > specified but unnecessary (David Rowley) > > Yes, I didn't like "specified" myself but never returned to improve it. > I am now using: > > Allow window functions to use the faster <link > linkend="syntax-window-functions"><literal>ROWS</literal></link> mode > internally when <literal>RANGE</literal> mode is active but > unnecessary > ------ > (David Rowley) > > Can that be improved?
Looks good to me. > > Also, I was hoping to be mentioned 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 default, but unnecessary (David Rowley, Erwin > > Brandstetter) > > Uh, I have CC'ed David Rowley because that is unclear based on the > commit message. I don't normally mention reviewers. I confirm that Erwin reported in [1] that row_number() is not affected by the ROWS/RANGE option and that ROWS performs better due to the executor having less work to do. I am the author of the patch which implemented that plus a few other window functions that also can benefit from the same optimisation. Based on this, I don't see any problems with the credits for this item as they are currently in the release notes. David [1] https://postgr.es/m/CAGHENJ7LBBszxS%2BSkWWFVnBmOT2oVsBhDMB1DFrgerCeYa_DyA%40mail.gmail.com
