节点JS和pg模块'我怎么能真正关闭连接？' [英] Node JS and pg module 'How can I really close connection?'

问题描述

我对节点pg模块感到疯狂，已经有太多客户端错误。

I'm going crazy with node pg module, getting 'too many clients already' error.

我的 app.js 文件管理我查询一些数据到postgres的一些路由。 app.js 看起来如下：

My app.js file for example, manages some routes in which I query some data to postgres. app.js looks like bellow:

//First I create a client
var client = new pg.Client(connectionString);
// Then I use that client to every routes, for example:
ContPg.prototype.someController = function(req, res){
    client.connect(function(error){
        if(error) return console.error('error conectando', error); 
        // Need to close client if there's an error connecting??

        client.query(someQuery, function(e,r){
            client.end(); 
            // Here sometimes I dont end client if i need to query more data 
            if(e) return console.error('error consultando', e);
            // Do anything with result...
        })
    });
}

正如我所说，我将该客户端用于文件<$ c $中的所有路径c> pg.js ，但是在其他路由的其他文件中我也会这样做以连接到postgres（创建客户端并用于管理该文件的所有路由）

As I said I use that client for all routes in file pg.js, but in other files with other routes I do the same to connect to postgres (create client and use for all routes that manage that file)

问题

我的代码有问题吗？我结束了错误的客户连接？
如果没有任何问题，可能导致已经有太多客户的错误？

Is something wrong with my code? I ended wrong client connection? If there's nothing wrong, what could be causing 'too many clients already' error?

提前致谢!!

推荐答案

推荐的模式是使用客户端池。来自 node-postgres 文档：

The recommended pattern is to use client pooling. From the node-postgres documentation:

通常，您将通过
客户端池访问PostgreSQL服务器。客户端需要花费大量时间来建立
的新连接。客户端还在PostgreSQL服务器上消耗了大量的
资源 - 这不是你想要在
每个http请求上做的事情。好消息：node-postgres附带内置的
客户端池。

Generally you will access the PostgreSQL server through a pool of clients. A client takes a non-trivial amount of time to establish a new connection. A client also consumes a non-trivial amount of resources on the PostgreSQL server - not something you want to do on every http request. Good news: node-postgres ships with built in client pooling.

var pg = require('pg');
var conString = "postgres://username:password@localhost/database";

//this initializes a connection pool
//it will keep idle connections open for a (configurable) 30 seconds
//and set a limit of 20 (also configurable)
pg.connect(conString, function(err, client, done) {
  if(err) {
    return console.error('error fetching client from pool', err);
  }
  client.query('SELECT $1::int AS number', ['1'], function(err, result) {
    //call `done()` to release the client back to the pool
    done();

    if(err) {
      return console.error('error running query', err);
    }
    console.log(result.rows[0].number);
    //output: 1
  });
});

不要忘记致电 done（）或者你会遇到麻烦！

Don't forget to call done() or you'll be in trouble!

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