Hello hackers,
I've repeated the performance measurement for REL_17_STABLE (1e020258e)
and REL_16_STABLE (6f6b0f193) and found several benchmarks where v16 is
significantly better than v17. Please find attached an html table with
all the benchmarking results.
I had payed attention to:
Best pg-src-17--.* worse than pg-src-16--.* by 57.9 percents (225.11 > 142.52): pg_tpcds.query15
Average pg-src-17--.* worse than pg-src-16--.* by 55.5 percents (230.57 > 148.29): pg_tpcds.query15
in May, performed `git bisect` for this degradation, that led me to commit
b7b0f3f27 [1].
This time I bisected the following anomaly:
Best pg-src-17--.* worse than pg-src-16--.* by 23.6 percents (192.25 > 155.58): pg_tpcds.query21
Average pg-src-17--.* worse than pg-src-16--.* by 25.1 percents (196.19 > 156.85): pg_tpcds.query21
and to my surprise I got "b7b0f3f27 is the first bad commit".
Moreover, bisecting of another anomaly:
Best pg-src-17--.* worse than pg-src-16--.* by 24.2 percents (24269.21 > 19539.89): pg_tpcds.query72
Average pg-src-17--.* worse than pg-src-16--.* by 24.2 percents (24517.66 > 19740.12): pg_tpcds.query72
pointed at the same commit again.
So it looks like q15 from TPC-DS is not the only query suffering from that
change.
But beside that, I've found a separate regression. Bisecting for this degradation:
Best pg-src-17--.* worse than pg-src-16--.* by 105.0 percents (356.63 > 173.96): s64da_tpcds.query95
Average pg-src-17--.* worse than pg-src-16--.* by 105.2 percents (357.79 > 174.38): s64da_tpcds.query95
pointed at f7816aec2.
Does this deserve more analysis and maybe fixing?
[1] https://www.postgresql.org/message-id/63a63690-dd92-c809-0b47-af05459e95d1%40gmail.com
Best regards,
Alexander
