On Thu, 27 Jul 2023 at 16:01, Peter Geoghegan <p...@bowt.ie> wrote: > > On Thu, Jul 27, 2023 at 7:59 AM Matthias van de Meent > <boekewurm+postg...@gmail.com> wrote: > > > Basically, the patch that added that feature had to revise the index > > > AM API, in order to support a mode of operation where scans return > > > groupings rather than tuples. Whereas this patch requires none of > > > that. It makes affected index scans as similar as possible to > > > conventional index scans. > > > > Hmm, yes. I see now where my confusion started. You called it out in > > your first paragraph of the original mail, too, but that didn't help > > me then: > > > > The wiki does not distinguish "Index Skip Scans" and "Loose Index > > Scans", but these are not the same. > > A lot of people (myself included) were confused on this point for > quite a while.
I've taken the liberty to update the "Loose indexscan" wiki page [0], adding detail that Loose indexscans are distinct from Skip scans, and showing some high-level distinguishing properties. I also split the TODO entry for `` "loose" or "skip" scan `` into two, and added links to the relevant recent threads so that it's clear these are different (and that some previous efforts may have had a confusing name). I hope this will reduce the chance of future confusion between the two different approaches to improving index scan performance. Kind regards, Matthias van de Meent Neon (https://neon.tech) [0]: https://wiki.postgresql.org/wiki/Loose_indexscan
