| # hll-err.rb - Copyright (C) 2014 Salvatore Sanfilippo | |
| # BSD license, See the COPYING file for more information. | |
| # | |
| # This program is suited to output average and maximum errors of | |
| # the Redis HyperLogLog implementation in a format suitable to print | |
| # graphs using gnuplot. | |
| require 'rubygems' | |
| require 'redis' | |
| require 'digest/sha1' | |
| # Generate an array of [cardinality,relative_error] pairs | |
| # in the 0 - max range, with the specified step. | |
| # | |
| # 'r' is the Redis object used to perform the queries. | |
| # 'seed' must be different every time you want a test performed | |
| # with a different set. The function guarantees that if 'seed' is the | |
| # same, exactly the same dataset is used, and when it is different, | |
| # a totally unrelated different data set is used (without any common | |
| # element in practice). | |
| def run_experiment(r,seed,max,step) | |
| r.del('hll') | |
| i = 0 | |
| samples = [] | |
| step = 1000 if step > 1000 | |
| while i < max do | |
| elements = [] | |
| step.times { | |
| ele = Digest::SHA1.hexdigest(i.to_s+seed.to_s) | |
| elements << ele | |
| i += 1 | |
| } | |
| r.pfadd('hll',elements) | |
| approx = r.pfcount('hll') | |
| err = approx-i | |
| rel_err = 100.to_f*err/i | |
| samples << [i,rel_err] | |
| end | |
| samples | |
| end | |
| def filter_samples(numsets,max,step,filter) | |
| r = Redis.new | |
| dataset = {} | |
| (0...numsets).each{|i| | |
| dataset[i] = run_experiment(r,i,max,step) | |
| STDERR.puts "Set #{i}" | |
| } | |
| dataset[0].each_with_index{|ele,index| | |
| if filter == :max | |
| card=ele[0] | |
| err=ele[1].abs | |
| (1...numsets).each{|i| | |
| err = dataset[i][index][1] if err < dataset[i][index][1] | |
| } | |
| puts "#{card} #{err}" | |
| elsif filter == :avg | |
| card=ele[0] | |
| err = 0 | |
| (0...numsets).each{|i| | |
| err += dataset[i][index][1] | |
| } | |
| err /= numsets | |
| puts "#{card} #{err}" | |
| elsif filter == :absavg | |
| card=ele[0] | |
| err = 0 | |
| (0...numsets).each{|i| | |
| err += dataset[i][index][1].abs | |
| } | |
| err /= numsets | |
| puts "#{card} #{err}" | |
| elsif filter == :all | |
| (0...numsets).each{|i| | |
| card,err = dataset[i][index] | |
| puts "#{card} #{err}" | |
| } | |
| else | |
| raise "Unknown filter #{filter}" | |
| end | |
| } | |
| end | |
| if ARGV.length != 4 | |
| puts "Usage: hll-gnuplot-graph <samples> <max> <step> (max|avg|absavg|all)" | |
| exit 1 | |
| end | |
| filter_samples(ARGV[0].to_i,ARGV[1].to_i,ARGV[2].to_i,ARGV[3].to_sym) | |