If you want to search for something in parallel in Ruby, the thread gem is the way to go

parallel_search.rb

# gem install thread
require 'thread/pool'
require 'thread/channel'
require 'ruby-progressbar'

pool = Thread.pool 2
channel = Thread.channel
progress = ProgressBar.create totaL: 1_000_000

1_000_000.times do |i| 
	pool.process do
		# do a bunch of processing here
		sleep 1 
		# send your result here
		channel.send i if i == 9
		# update progress
		progress.increment
	end
end

# get your result here
puts "You were looking for the number #{channel.receive}"
# stop processing
pool.shutdown!