Em qua., 25 de mai. de 2022 às 00:46, Andres Freund <and...@anarazel.de> escreveu:
Hi Andres, thank you for taking a look. > > On 2022-05-24 12:28:20 -0300, Ranier Vilela wrote: > > Linux Ubuntu 64 bits (gcc 9.4) > > ./pgbench -M prepared -c $conns -j $conns -S -n -U postgres > > > > conns tps head tps patched > > 1 2918.004085 3190.810466 > > 10 12262.415696 17199.862401 > > 50 13656.724571 18278.194114 > > 80 14338.202348 17955.336101 > > 90 16597.510373 18269.660184 > > 100 17706.775793 18349.650150 > > 200 16877.067441 17881.250615 > > 300 16942.260775 17181.441752 > > 400 16794.514911 17124.533892 > > 500 16598.502151 17181.244953 > > 600 16717.935001 16961.130742 > > 700 16651.204834 16959.172005 > > 800 16467.546583 16834.591719 > > 900 16588.241149 16693.902459 > > 1000 16564.985265 16936.952195 > > 17-18k tps is pretty low for pgbench -S. For a shared_buffers resident > run, I > can get 40k in a single connection in an optimized build. If you're > testing a > workload >> shared_buffers, GetSnapshotData() isn't the bottleneck. And > testing an assert build isn't a meaningful exercise either, unless you have > way way higher gains (i.e. stuff like turning O(n^2) into O(n)). > Thanks for sharing these hits. Yes, their 17-18k tps are disappointing. > What pgbench scale is this and are you using an optimized build? > Yes this optimized build. CFLAGS='-Wall -Wmissing-prototypes -Wpointer-arith -Wdeclaration-after-statement -Werror=vla -Wendif-labels -Wmissing-format-attribute -Wimplicit-fallthrough=3 -Wcast-function-type -Wformat-security -fno-strict-aliasing -fwrapv -fexcess-precision=standard -Wno-format-truncation -Wno-stringop-truncation -O2' from config.log pgbench was initialized with: pgbench -i -p 5432 -d postgres pgbench -M prepared -c 100 -j 100 -S -n -U postgres pgbench (15beta1) transaction type: <builtin: select only> scaling factor: 1 query mode: prepared number of clients: 100 number of threads: 100 The shared_buffers is default: shared_buffers = 128MB Intel® Core™ i5-8250U CPU Quad Core RAM 8GB SSD 256 GB Can you share the pgbench configuration and shared buffers this benchmark? https://www.postgresql.org/message-id/20200301083601.ews6hz5dduc3w2se%40alap3.anarazel.de regards, Ranier Vilela
