看到这个gem https://github.com/mperham/connection_pool并回答，连接池可能是你需要的：Why not use shared ActiveRecord connections for Rspec + Selenium?
另一个选择是使用https://github.com/eventmachine/eventmachine并在EM.defer块中运行任务，这样数据库访问就以非阻塞的方式在回调块（在reactor内）中发生
或者，一个更健壮的解决方案，使用轻量级的后台处理队列，如beanstalkd，更多选项请参见https://www.ruby-toolbox.com/categories/Background_Jobs-这是我的主要建议
编辑，
而且，你可能没有200个核心，所以创建200多个并行线程和数据库连接并不能真正加速这个过程（实际上会减慢它），看看你是否能找到一种方法来将你的问题划分为等于你的核心数量+1的集合，并以这种方式解决问题，
这可能是解决您问题的最简单方法

好吧，我知道我的回答不适用于你的问题。但是，我想为Rails应用程序中的多线程数据库工作提供一种安全的方法。

正在运行的线程数应小于总数据库连接池大小。

这是第一条规则。所以我让忙碌运行的数据库连接的大小不应该达到总数据库连接池大小的一半。
如果您有10个DB连接池大小，则最大线程数为5。所以很安全。当你有少于5个可用的数据库连接时，它将作为单线程运行，然后当你有足够的数据库连接时，它将再次作为多线程运行。

def call
  if enough_db_connection?
    run_as_multi_thread(works, max_thread_count)
  else
    run_as_single_thread(works, max_thread_count)
  end
end

private

def enough_db_connection?
  (ActiveRecord::Base.connection_pool.stat[:size] / 2) > ActiveRecord::Base.connection_pool.stat[:busy]
end

def max_thread_count
  (ActiveRecord::Base.connection_pool.stat[:size] / 2)
end

def works
  @works ||= [some array of work..]
end

## running methods

def run_as_multi_thread(works, max_thread_count)
  # puts "We have enough db connection. Lets running it as multi thread."
  works = works.take(max_thread_count)
  rest_of_works = works.drop(max_thread_count)

  works.map do |work|
    Thread.new do
      ActiveRecord::Base.transaction do
        work.do_some_work # Do some work 
      end
    end
  end.each(&:join)

  if rest_of_works.size.positive?
    if enough_db_connection?
      run_as_multi_thread(rest_of_works, max_thread_count)
    else
      run_as_single_thread(rest_of_works, max_thread_count)
    end
  end
end

def run_as_single_thread(works, max_thread_count)
  # puts "We don't have enough db connection now. Cuurent Busy Running DB connection size is bigger than #{max_thread_count}. Let's running it as single thread."
  works = works.take(max_thread_count)
  rest_of_works = works.drop(max_thread_count)

  works.map do |work|
    ActiveRecord::Base.transaction do
      work.do_some_work # Do some work  
    end
  end

  if rest_of_works.size.positive?
    if enough_db_connection?
      run_as_multi_thread(rest_of_works, max_thread_count)
    else
      run_as_single_thread(rest_of_works, max_thread_count)
    end
  end
end