'each commit' vs 'transaction' vs 'bulk_insert'

benchmark.rb

require 'benchmark'

def each_commit(size)
  project = Project.create!(name: "each_commit #{size}")
  size.times.with_index(1) do |_, index|
    project.tasks.create!(name: "Task #{index}")
  end
end

def transaction(size)
  ActiveRecord::Base.transaction do
    project = Project.create!(name: "transaction #{size}")
    size.times.with_index(1) do |_, index|
      project.tasks.create!(name: "Task #{index}")
    end
  end
end

def bulk_insert(size)
  project = Project.create!(name: "bulk_insert #{size}")
  tasks = (1..size).map do |index|
    Task.new(name: "Task #{index}", project_id: project.id)
  end
  Task.import(tasks)
end

def benchmark(size)
  puts "** #{size}レコードのデータを保存"
  Benchmark.bm(16) do |b|
    %w(each_commit transaction bulk_insert).each do |method|
      b.report(method) { send(method.to_sym, size) }
    end
  end
end

[100, 1000, 10000].each do |record_size|
  benchmark(record_size)
end

result.txt

** 100レコードのデータを保存
                       user     system      total        real
each_commit        0.410000   0.100000   0.510000 (  0.570270)
transaction        0.310000   0.020000   0.330000 (  0.322642)
bulk_insert        0.020000   0.000000   0.020000 (  0.026268)

** 1000レコードのデータを保存
                       user     system      total        real
each_commit        3.900000   0.620000   4.520000 (  4.971859)
transaction        3.980000   0.160000   4.140000 (  4.144867)
bulk_insert        0.230000   0.010000   0.240000 (  0.229818)

** 10000レコードのデータを保存
                       user     system      total        real
each_commit       80.330000   6.840000  87.170000 ( 91.277122)
transaction      124.760000   8.700000 133.460000 (133.544246)
bulk_insert        2.260000   0.020000   2.280000 (  2.292815)