results

Using events with 6144 elements
Warming up --------------------------------------
                each     1.000  i/100ms
                 map     1.000  i/100ms
          map + uniq     1.000  i/100ms
           map + set     1.000  i/100ms
   chunked by thread     1.000  i/100ms
   chunked by thread     1.000  i/100ms
Calculating -------------------------------------
                each      2.569  (± 3.7%) i/s -     26.000  in  10.237953s
                 map      2.379  (± 3.7%) i/s -     24.000  in  10.203514s
          map + uniq      2.536  (± 3.7%) i/s -     26.000  in  10.362150s
           map + set      1.391  (± 4.4%) i/s -     14.000  in  10.164477s
   chunked by thread      0.022  (± 0.0%) i/s -      1.000  in  45.246803s
   chunked by thread      0.021  (± 0.0%) i/s -      1.000  in  48.178517s
                   with 95.0% confidence
Comparison:
                each:        2.6 i/s
          map + uniq:        2.5 i/s - same-ish: difference falls within error
                 map:        2.4 i/s - 1.08x  (± 0.06) slower
           map + set:        1.4 i/s - 1.85x  (± 0.11) slower
   chunked by thread:        0.0 i/s - 123.81x  (± 4.61) slower
                   with 95.0% confidence

test_logstash_sprintf_like_methods.rb

# needs benchmark-ips kalibera
require 'benchmark'
require 'benchmark/ips'
require 'set'

n = 100

events = [
  {"something" => "apple"},
  {"something" => "apple"},
  {"something" => "kiwi"},
  {"something" => "kiwi"},
  {"something" => "orange"},
  {"something" => "orange"}
]

10.times do |_|
  events << events.dup
  events.flatten!
end

puts "Using events with #{events.count} elements"

Benchmark.ips(10) do |b|
  b.config(:stats => :bootstrap) #, :iterations => 3)

  b.report('each') do
    seen = {}
    n.times do
      events.each do |e|
        s = sprintf("%s", e["something"])
        seen[s] = s
      end
    end
    # puts seen
  end

  b.report('map') do
    seen = {}
    n.times do
      events.map { |e| sprintf("%s", e["something"]) }.each do |s|
        seen[s] = s
      end
    end
    # puts seen
  end

  b.report('map + uniq') do
    seen = {}
    n.times do
      events.map { |e| sprintf("%s", e["something"]) }.uniq.each do |s|
        seen[s] = s
      end
    end
    # puts seen
  end

  b.report('map + set') do
    seen = {}
    n.times do
      Set[events.map { |e| sprintf("%s", e["something"]) }].each do |s|
        seen[s] = s
      end
    end
    # puts seen
  end

  b.report('chunked by thread') do
    seen = {}
    n.times do
      pool = []
      events.each_slice(2) do |chunk|
        pool << Thread.new(chunk) { |c|
          c.each do |e|
            s = sprintf("%s", e["something"])
            seen[s] = s
          end
        }
      end
      pool.map(&:join)
      pool.map(&:kill)
    end
  end

  b.compare!
end