Imai-san, Thanks for testing.
On 2019/01/24 15:09, Imai, Yoshikazu wrote: > [pgbench commands] > pgbench -n -f update.sql -T 30 postgres > > [update.sql(updating partkey case)] > update rt set a = 1; > > [update.sql(updating non-partkey case)] > update rt set b = 1; > > [results] > 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 > > > updating non-partkey case: > > part-num master 0001 0002 0003 0004 > 1 8862.58 8421.49 8575.35 9843.71 10065.30 > 2 7715.05 7575.78 7654.28 8800.84 8720.60 > 4 6249.95 6321.32 6470.26 7278.14 7280.10 > 8 4514.82 4730.48 4823.37 5382.93 5341.10 > 16 2815.21 3123.27 3162.51 3422.36 3393.94 > 32 968.45 1702.47 1722.38 1809.89 1799.88 > 64 364.17 420.48 432.87 440.20 435.31 > 128 119.94 148.77 150.47 152.18 143.35 > 256 45.09 46.35 46.93 48.30 45.85 > 512 8.74 10.59 10.23 10.27 10.13 > 1024 2.28 2.60 2.56 2.57 2.51 > > > Looking at the results, if we only apply 0001 or 0001 + 0002 and if number of > partition is few like 1 or 2, performance degrades compare to master(A > maximum reduction is about 5%, which is 8863->8421). > In all other cases, performance improves compare to master. Just to be clear, these are cases where pruning *doesn't* occur, though we'll still need to at least figure out why the degradation occurs for small number of partitions. Thanks, Amit
