Benchmark about rescue exceptions

bm-rescue-vs-check-ips.rb

require 'benchmark/ips'

Benchmark.ips do |bm|
  path = "/tmp/unknown_file.unknown_ext"

  bm.report("using rescue") do
    begin
      File.read(path)
    rescue
      "file doesn't exist"
    end
  end

  bm.report("checking if file exists") do
    if File.exists?(path)
      File.read(path)
    else
      "file doesn't exist"
    end
  end
end

bm-rescue-vs-check.rb

require 'benchmark'

iterations = 1_000_000

Benchmark.bm(27) do |bm|
  path = "/tmp/unknown_file.unknown_ext"

  bm.report("using rescue") do
    iterations.times do
      begin
        File.read(path)
      rescue
        "file doesn't exist"
      end
    end
  end

  bm.report("checking if file exists") do
    iterations.times do
      if File.exists?(path)
        File.read(path)
      else
        "file doesn't exist"
      end
    end
  end
end

results

                                  user     system      total        real
using rescue                  9.870000   1.490000  11.360000 ( 11.513433)
checking if file exists       0.440000   0.660000   1.100000 (  1.102379)

results-ips

Calculating -------------------------------------
        using rescue      7454 i/100ms
checking if file exists
                         45063 i/100ms
-------------------------------------------------
        using rescue    85105.1 (±1.6%) i/s -     432332 in   5.081270s
checking if file exists
                       807410.8 (±2.9%) i/s -    4055670 in   5.027569s