clone_via_threading.rb

def clone_table(src_db, dest_db, table)
  # filter the rows to be exported
  dataset = src_db[table]

  # truncate if no key_field
  unless key_field
    puts "truncating #{table}..."
    dest_db[table].delete 
  end

  puts "counting records..."
  records = dataset.count
  puts "exporting #{records} records for #{table.to_s}"
  pbar = ProgressBar.new(table.to_s, records)

  threads = []
  dataset.each_slice(records / 4) do |rows|
    threads << Thread.new(table, rows, threads.size) do |table, rows, i|
      puts "starting thread #{i} with #{rows.size}"
      dest_db = Sequel.connect("jdbc:sqlserver://10.0.1.2:1348;databaseName=Michaels Test Practice", :user => 'admin', :password => 'thisaintit')
      rows.each do |values|
         dest_db[table].insert(values)
         pbar.inc
      end
      puts "finished thread #{i}"
    end
  end
  threads.each_with_index{|t, i| puts "joining #{i}"; t.join}
  pbar.finish
end