Very rough look at parsing speed across marc and marc4j.

marc_vs_marc4j_bench.rb

# A very, *very* imperfect bench, but gives us a rough idea
#
# tl;dr -- marc-binary is a wash, marc-xml is about 3.5 times faster using marc4j
#
# > bundle exec ruby --server bench.rb
# jruby 9.2.0.0 (2.5.0) 2018-05-24 81156a8 Java HotSpot(TM) 64-Bit Server VM 25.112-b16 on 1.8.0_112-b16 +jit [darwin-x86_64]
# Warmup: 45. Runtime: 15
#
# Comparison:
#           marc4j-xml:     8197.4 i/s
#          marc-binary:     5463.2 i/s - 1.50x  slower
#        marc4j-binary:     5262.6 i/s - 1.56x  slower
#             marc-xml:     2315.9 i/s - 3.54x  slower
#
# Turning on invokedynamic didn't change the raw speed or the ratios outside of the stdev

require 'marc'
require 'traject'
require 'benchmark/ips'
require 'nokogiri'


# Need a way to not run out of records to parse. I just keep
# opening the input file over and over again as needed
class InfiniteBinaryIterator

  include Enumerable


  def self.iterator(klass, file)
    instance = self.new(klass, file)
    instance.enum_for(:each)
  end


  def initialize(klass, file)
    @klass = klass
    @file  = file
  end


  def each
    return enum_for(:each) unless block_given?
    loop do
      File.open(@file, 'rb') do |f|
        reader = @klass.new(f, {})
        reader.each {|x| yield x}
      end
    end
  end
end

class InfiniteXMLIterator < InfiniteBinaryIterator

  def each
    return enum_for(:each) unless block_given?
    loop do
      File.open(@file, 'r:utf-8') do |f|
        reader = @klass.new(f, {'marc_source.type' => 'xml', "marc_reader.xml_parser"=> 'nokogiri'})
        reader.each {|x| yield x}
      end
    end
  end
end

binary_file = '100_000.marc'
xml_file    = '100_000.xml'

mb = InfiniteBinaryIterator.iterator(Traject::MarcReader, binary_file)
mx = InfiniteXMLIterator.iterator(Traject::MarcReader, xml_file)

m4jb = InfiniteBinaryIterator.iterator(Traject::Marc4JReader, binary_file)
m4jx = InfiniteXMLIterator.iterator(Traject::Marc4JReader, xml_file)


warmup = 45
runtime = 15

puts RUBY_DESCRIPTION
puts "Warmup: #{warmup}. Runtime: #{runtime}\n\n"

Benchmark.ips do |x|
  x.config(:time => runtime, :warmup => warmup)

  title_length = 0
  x.report('marc4j-binary') do
    title_length += m4jb.next['245'].value.size
  end

  title_length = 0
  x.report('marc4j-xml') do
    title_length += m4jx.next['245'].value.size
  end

  title_length = 0
  x.report('marc-binary') do
    title_length += mb.next['245'].value.size
  end

  title_length = 0
  x.report('marc-xml') do
    title_length += mx.next['245'].value.size
  end

  x.compare!

end