gistfile1.txt

$ export AWS_ACCESS_KEY_ID='change me'
$ export AWS_SECRET_ACCESS_KEY='change me'
$ export AWS_REGION='change me'
$ gem install aws-sdk
$ ruby setup.rb
$ ruby repro.rb

repro.rb

require 'aws-sdk'
require 'json'

Thread.abort_on_exception = true

puts 'Starting...'

threads = 10.times.map do
  Thread.new do
    sqs    = Aws::SQS::Client.new
    url    = sqs.get_queue_url(:queue_name => 'example').queue_url
    poller = Aws::SQS::QueuePoller.new(url)

    poller.poll(:idle_timeout => 5) do |message|
      JSON.load(message.body)
    end
  end
end

threads.each(&:join)

setup.rb

require 'aws-sdk'
require 'json'

sqs      = Aws::SQS::Client.new
response = sqs.create_queue(:queue_name => 'example')

100.times do |number|
  sqs.send_message(
    :queue_url    => response.queue_url,
    :message_body => JSON.dump([number])
  )
end