On Sun, Mar 31, 2019 at 12:11 AM Tom Lane <t...@sss.pgh.pa.us> wrote: > Amit Langote <amitlangot...@gmail.com> writes: > > I think the performance results did prove that degradation due to > > those loops over part_rels becomes significant for very large > > partition counts. Is there a better solution than the bitmapset that > > you have in mind? > > Hm, I didn't see much degradation in what you posted in > <5c83dbca-12b5-1acf-0e85-58299e464...@lab.ntt.co.jp>.
Sorry that I didn't mention the link to begin with, but I meant to point to numbers that I reported on Monday this week. https://www.postgresql.org/message-id/19f54c17-1619-b228-10e5-ca343be6a4e8%40lab.ntt.co.jp You were complaining of the bitmapset being useless overhead for small partition counts, but the numbers I get tend to suggest that any degradation in performance is within noise range, whereas the performance benefit from having them looks pretty significant for very large partition counts. > I am curious as to why there seems to be more degradation > for hash cases, as per Yoshikazu-san's results in > <0F97FA9ABBDBE54F91744A9B37151A512BAC60@g01jpexmbkw24>, > but whatever's accounting for the difference probably > is not that. I suspected it may have been the lack of bitmapsets, but maybe only Imai-san could've confirmed that by applying the live_parts patch too. Thanks, Amit
