R数值向量列表 - >带有Rcpp的C ++ 2d数组(R List of numeric vectors -> C++ 2d array with Rcpp)

 不幸的是，没有办法通过当前的API一次获得多个线程主题。 但是，您可以采取一些措施来改善性能： 
 
 
 
 使用API​​的分页功能一次获取有限数量的线程。 
 
 
 并行获取批量消息，而不是一次尝试获取所有消息或一次获取所有消息。 为自己做实验，但5开始时就是一个很好的数字。 
 
 
 如果这是一个浏览器实现，请考虑拨打后端，而不是从浏览器拨打电话。 这样，客户端每页只进行1次调用，它允许您为服务器添加缓存和预加载机制，从而改善客户体验。 这里潜在的缺点是可扩展性; 随着您获得更多客户端，您将需要比胖客户端方法更多的处理能力。 
 
 
 作为＃2的示例，您最初可以获取5，然后让每个函数的回调触发下一个调用，因此总是有5个并发获取： 
 
var CONCURRENCY_LIMIT = 5;

function getThread(threadId, done) {
  threadRequest.id = e.id;
  gmail.api.users.threads.get(threadRequest).execute(function(thread) {
    showThread();
    done();
  });
}

gmail.api.users.threads.list({userId:myUserId}).execute(function(threads) { 
  function fetchNextThread() {
    var nextThread = threads.shift();
    nextThread.id && getThread(nextThread.id, fetchNextThread);
  }

  for (var i = 0; i < CONCURRENCY_LIMIT; i++) {
    fetchNextThread();
  }
});

Unfortunately, there isn't a way to get more than one thread subject at a time through the current API. However, there are a few things you might do to improve the performance:
 
 
 
Use the API's paging feature to fetch limited amounts of threads at once.
 
 
Fetch batches of messages in parallel rather than attempting to fetch all at once or one at a time. Experiment for yourself, but 5 would be a good number to start with.
 
 
If this is a browser implementation, consider making a call to your back-end instead of making the calls from the browser. This way the client only makes 1 call per page, and it allows you to potentially add caching and pre-loading mechanisms to your server that will improve the customer experience. The potential downside here is scalability; as you get more clients, you'll need considerably more processing power than an fat-client approach.
 
 
As an example of #2, you could fetch 5 initially, and then have the callback for each function fire the next call so there are always 5 fetching concurrently:
 
var CONCURRENCY_LIMIT = 5;

function getThread(threadId, done) {
  threadRequest.id = e.id;
  gmail.api.users.threads.get(threadRequest).execute(function(thread) {
    showThread();
    done();
  });
}

gmail.api.users.threads.list({userId:myUserId}).execute(function(threads) { 
  function fetchNextThread() {
    var nextThread = threads.shift();
    nextThread.id && getThread(nextThread.id, fetchNextThread);
  }

  for (var i = 0; i < CONCURRENCY_LIMIT; i++) {
    fetchNextThread();
  }
});