On Tue, 23 Jul 2019 at 19:26, Fabien COELHO <coe...@cri.ensmp.fr> wrote:
> > Hello devs, > > While doing some performance tests and reviewing patches, I needed to > create partitioned tables. Given the current syntax this is time > consumming. > Good idea. I wonder why we didn't have it already. > The attached patch adds two options to create a partitioned "account" > table in pgbench. > > It allows to answer quickly simple questions, eg "what is the overhead of > hash partitioning on a simple select on my laptop"? Answer: > > # N=0..? > sh> pgench -i -s 1 --partition-number=$N --partition-type=hash > Given current naming of options, I would call this --partitions=number-of-partitions and --partition-method=hash > # then run > sh> pgench -S -M prepared -P 1 -T 10 > > # and look at latency: > # no parts = 0.071 ms > # 1 hash = 0.071 ms (did someone optimize this case?!) > # 2 hash ~ 0.126 ms (+ 0.055 ms) > # 50 hash ~ 0.155 ms > # 100 hash ~ 0.178 ms > # 150 hash ~ 0.232 ms > # 200 hash ~ 0.279 ms > # overhead ~ (0.050 + [0.0005-0.0008] * nparts) ms > It is linear? -- Simon Riggs http://www.2ndQuadrant.com/ <http://www.2ndquadrant.com/> PostgreSQL Solutions for the Enterprise
