Re: Streaming read-ready sequential scan code

On Sat, May 18, 2024 at 1:00 AM Alexander Lakhin <exclusion@gmail.com> wrote:
> I decided to compare v17 vs v16 performance (as I did the last year [1])
> and discovered that v17 loses to v16 in the pg_tpcds (s64da_tpcds)
> benchmark, query15 (and several others, but I focused on this one):
> Best pg-src-master--.* worse than pg-src-16--.* by 52.2 percents (229.84 > 151.03): pg_tpcds.query15
> Average pg-src-master--.* worse than pg-src-16--.* by 53.4 percents (234.20 > 152.64): pg_tpcds.query15
> Please look at the full html report attached in case you're interested.
>
> (I used my pg-mark tool to measure/analyze performance, but I believe the
> same results can be seen without it.)

Will investigate, but if it's easy for you to rerun, does it help if
you increase Linux readahead, eg blockdev --setra setting?