ExpressJS - 如何处理同步请求？请求似乎彼此阻止。

I have the following piece of code

我有以下代码

var express = require('express');
var routes = require('./routes');    
var http = require('http');
...
app.get('/a',function(){
  Card.findCards(function(err, result){  //Mongoose schema
    res.send(result); //Executes a query with 9000 records
  })  
});
app.get('/b', function(req, res){
  res.send("Hello World");
});
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