Imai-san, On 2019/01/28 10:44, Imai, Yoshikazu wrote: > On Thu, Jan 24, 2019 at 6:10 AM, Imai, Yoshikazu wrote: >> updating partkey case: >> >> part-num master 0001 0002 0003 0004 >> 1 8215.34 7924.99 7931.15 8407.40 8475.65 >> 2 7137.49 7026.45 7128.84 7583.08 7593.73 >> 4 5880.54 5896.47 6014.82 6405.33 6398.71 >> 8 4222.96 4446.40 4518.54 4802.43 4785.82 >> 16 2634.91 2891.51 2946.99 3085.81 3087.91 >> 32 935.12 1125.28 1169.17 1199.44 1202.04 >> 64 352.37 405.27 417.09 425.78 424.53 >> 128 236.26 310.01 307.70 315.29 312.81 >> 256 65.36 86.84 87.67 84.39 89.27 >> 512 18.34 24.84 23.55 23.91 23.91 >> 1024 4.83 6.93 6.51 6.45 6.49 > > I also tested with non-partitioned table case. > > updating partkey case: > > part-num master 0001 0002 0003 0004 > 0 10956.7 10370.5 10472.6 10571.0 10581.5 > 1 8215.34 7924.99 7931.15 8407.40 8475.65 > ... > 1024 4.83 6.93 6.51 6.45 6.49 > > > In my performance results, it seems update performance degrades in > non-partitioned case with v17-patch applied. > But it seems this degrades did not happen at v2-patch. > > On Thu, Aug 30, 2018 at 1:45 AM, Amit, Langote wrote: >> UPDATE: >> >> nparts master 0001 0002 0003 >> ====== ====== ==== ==== ==== >> 0 2856 2893 2862 2816 > > Does this degradation only occur in my tests? Or if this result is correct, > what may causes the degradation?
I re-ran tests with v18 using the following setup [1]: create table ht (a int, b int) partition by hash (b); create table ht_0 partition of ht for values with (modulus N, remainder 0); ... $ cat update-noprune.sql update ht set a = 0; pgbench -n -T 60 -f update-noprune,sql TPS: nparts master 0001 0002 0003 0004 ====== ====== ==== ==== ==== ==== 0 4408 4335 4423 4379 4314 1 3883 3873 3679 3856 4007 2 3495 3476 3477 3500 3627 I can see some degradation for small number of partitions, but maybe it's just noise? At least, I don't yet have a systematic explanation for that happening. Thanks, Amit [1] I changed the compile flags in build scripts to drop -DCATCACHE_FORCE_RELEASE, which would cause many syscache misses in my test runs
