On Tue, Aug 8, 2023 at 3:10 AM Andres Freund <and...@anarazel.de> wrote: > > Hi, > > On 2023-08-07 23:05:39 +0900, Masahiko Sawada wrote: > > On Mon, Aug 7, 2023 at 3:16 PM David Rowley <dgrowle...@gmail.com> wrote: > > > > > > On Wed, 2 Aug 2023 at 13:35, David Rowley <dgrowle...@gmail.com> wrote: > > > > So, it looks like this item can be closed off. I'll hold off from > > > > doing that for a few days just in case anyone else wants to give > > > > feedback or test themselves. > > > > > > Alright, closed. > > > > IIUC the problem with multiple concurrent COPY is not resolved yet. > > Yea - it was just hard to analyze until the other regressions were fixed. > > > > The result of nclients = 1 became better thanks to recent fixes, but > > there still seems to be the performance regression at nclient = 2~16 > > (on RHEL 8 and 9). Andres reported[1] that after changing > > MAX_BUFFERED_TUPLES to 5000 the numbers became a lot better but it > > would not be the solution, as he mentioned. > > I think there could be a quite simple fix: Track by how much we've extended > the relation previously in the same bistate. If we already extended by many > blocks, it's very likey that we'll do so further. > > A simple prototype patch attached. The results for me are promising. I copied > a smaller file [1], to have more accurate throughput results at shorter runs > (15s).
Thank you for the patch! > > HEAD before: > clients tps > 1 41 > 2 76 > 4 136 > 8 248 > 16 360 > 32 375 > 64 317 > > > HEAD after: > clients tps > 1 43 > 2 80 > 4 155 > 8 280 > 16 369 > 32 405 > 64 344 > > Any chance you could your benchmark? I don't see as much of a regression vs 16 > as you... Sure. The results are promising for me too: nclients = 1, execution time = 13.743 nclients = 2, execution time = 7.552 nclients = 4, execution time = 4.758 nclients = 8, execution time = 3.035 nclients = 16, execution time = 2.172 nclients = 32, execution time = 1.959 nclients = 64, execution time = 1.819 nclients = 128, execution time = 1.583 nclients = 256, execution time = 1.631 Here are results of the same benchmark test you used: w/o patch: clients tps 1 66.702 2 59.696 4 73.783 8 168.115 16 400.134 32 574.098 64 565.373 128 526.303 256 591.751 w/ patch: clients tps 1 67.735 2 122.534 4 240.707 8 398.944 16 541.097 32 643.083 64 614.775 128 616.007 256 577.885 Regards, -- Masahiko Sawada Amazon Web Services: https://aws.amazon.com