exception-bm.rb

require "bundler/inline"

gemfile do
  source "https://rubygems.org"

  gem "activerecord", "7.1.3.4"
  gem "sqlite3"
  gem "benchmark-ips"
end

require "active_record"

ActiveRecord::Base.establish_connection(adapter: 'sqlite3', database: ':memory:')
ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord::Schema.define do
  create_table :records do |t|
    t.string :attribute_that_must_not_be_blank
    t.datetime :created_at, null: false
    t.datetime :updated_at, null: false
  end
end

class Record < ActiveRecord::Base
  validates :attribute_that_must_not_be_blank, presence: true
end

# warmup AR
Record.create(attribute_that_must_not_be_blank: "foo")

Benchmark.ips do |x|
  x.report("exception") do
    record = Record.new

    begin
      record.save!
      # if
    rescue ActiveRecord::RecordInvalid
      # else
    end
  end

  x.report("if else") do
    record = Record.new

    if record.save
      # if
    else
      # else
    end
  end

  x.compare!
end

# Warming up --------------------------------------
#            exception   787.000 i/100ms
#              if else     3.329k i/100ms
# Calculating -------------------------------------
#            exception      7.774k (± 3.1%) i/s -     39.350k in   5.067153s
#              if else     33.353k (± 3.4%) i/s -    169.779k in   5.096774s

# Comparison:
#              if else:    33352.6 i/s
#            exception:     7773.6 i/s - 4.29x  slower