File.open('filename').each_line do |line|
  color, x, y = line.split
end

#6 楼 @dcy http://ruby-china.org/topics/new

会不会是 js 一些操作耗时或者读取外部资源耗时？

MongoDB 没有固定模式，所以要读取一条数据才能确定它有什么字段和类型。

Mongoid 的话用 ModelName.fields 可以获得自己在 Model 里面定义的字段信息。

whenever，了解下系统的 cron

#7 楼 @jfreebird 期待你拼装出一个 Rails。

#8 楼 @sanivbyfish 晕，我以为在说 ActiveRecord。

mongoid 是 order_by http://mongoid.org/en/origin/docs/options.html#sorting

#6 楼 @sanivbyfish 贴一下你加上 order 后的代码

#4 楼 @sanivbyfish commects 不是一个 associations（has_many）吗？

post.commects.order("xxx DESC").each

如果所有的 comments 都需要这个 order，可以加 default_scope

#2 楼 @beihuiguixian 是的。

可以放在 lib/ 下面。

喜欢 Mailgun 的 api 和文档，Postmark 网站设计太刺了。

推荐楼主一本书 http://book.douban.com/subject/3288908/ 集体智慧编程

编程不是目的，编程去解决问题才是目的，所以要知道你要解决什么问题才知道需要用什么知识。

顺便，我把模板从 erb 换到 slim，发现性能有提升

- 128000.times do
  = rand(8999)+1000

Server Software:        nginx/1.2.3
Server Hostname:        localhost
Server Port:            4000

Document Path:          /
Document Length:        512450 bytes

Concurrency Level:      10
Time taken for tests:   6.919 seconds
Complete requests:      100
Failed requests:        0
Write errors:           0
Total transferred:      51319300 bytes
HTML transferred:       51245000 bytes
Requests per second:    14.45 [#/sec] (mean)
Time per request:       691.885 [ms] (mean)
Time per request:       69.188 [ms] (mean, across all concurrent requests)
Transfer rate:          7243.47 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:        0    0   0.1      0       0
Processing:   454  672 103.5    677     911
Waiting:      454  670 103.8    673     910
Total:        454  672 103.5    677     911

Percentage of the requests served within a certain time (ms)
  50%    677
  66%    709
  75%    753
  80%    778
  90%    808
  95%    864
  98%    880
  99%    911
 100%    911 (longest request)

Started GET "/" for 127.0.0.1 at 2012-11-24 22:26:31 +0800
Processing by MainController#index as */*
  Rendered main/index.html.slim within layouts/application (703.5ms)
Completed 200 OK in 905ms (Views: 704.9ms | ActiveRecord: 0.0ms)
  Rendered main/index.html.slim within layouts/application (482.9ms)
Completed 200 OK in 685ms (Views: 484.5ms | ActiveRecord: 0.0ms)

循环放在 View 里面的日志

Started GET "/" for 127.0.0.1 at 2012-11-24 22:20:45 +0800
Processing by MainController#index as */*
  Rendered main/index.html.erb within layouts/application (1670.9ms)
Completed 200 OK in 1873ms (Views: 1672.4ms | ActiveRecord: 0.0ms)

移出后的日志

Started GET "/" for 127.0.0.1 at 2012-11-24 22:23:24 +0800
Processing by MainController#index as */*
  Rendered main/index.html.erb within layouts/application (1.6ms)
Completed 200 OK in 410ms (Views: 3.1ms | ActiveRecord: 0.0ms)

可见效率是有差异的。不过我觉得一般不会用到 128000 这么大的循环，View 按正常写就行了。

测试了一下，用 passenger start -p 4000 -e production --max-pool-size 100 --min-instances 10 启动

ab -c 10 -n 100 http://localhost:4000/

按原文的代码

Server Software:        nginx/1.2.3
Server Hostname:        localhost
Server Port:            4000

Document Path:          /
Document Length:        512451 bytes

Concurrency Level:      10
Time taken for tests:   21.563 seconds
Complete requests:      100
Failed requests:        0
Write errors:           0
Total transferred:      51319400 bytes
HTML transferred:       51245100 bytes
Requests per second:    4.64 [#/sec] (mean)
Time per request:       2156.277 [ms] (mean)
Time per request:       215.628 [ms] (mean, across all concurrent requests)
Transfer rate:          2324.22 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:        0    0   0.1      0       0
Processing:  1273 2107 311.6   2128    2994
Waiting:     1273 2106 311.6   2128    2994
Total:       1273 2107 311.7   2128    2994

Percentage of the requests served within a certain time (ms)
  50%   2128
  66%   2290
  75%   2336
  80%   2362
  90%   2460
  95%   2544
  98%   2747
  99%   2994
 100%   2994 (longest request)

把 view 里面的循环移到 controller

class MainController < ApplicationController
  def index
    sleep(0.2)
    @content = 128000.times.map{rand(8999)+1000}.join
  end
end

<%= @content %>

结果有了不少改善

Server Software:        nginx/1.2.3
Server Hostname:        localhost
Server Port:            4000

Document Path:          /
Document Length:        512451 bytes

Concurrency Level:      10
Time taken for tests:   4.817 seconds
Complete requests:      100
Failed requests:        0
Write errors:           0
Total transferred:      51319400 bytes
HTML transferred:       51245100 bytes
Requests per second:    20.76 [#/sec] (mean)
Time per request:       481.690 [ms] (mean)
Time per request:       48.169 [ms] (mean, across all concurrent requests)
Transfer rate:          10404.33 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:        0    0   0.1      0       0
Processing:   363  466  97.4    442     768
Waiting:      362  465  97.2    442     768
Total:        363  466  97.4    442     768

Percentage of the requests served within a certain time (ms)
  50%    442
  66%    480
  75%    502
  80%    513
  90%    593
  95%    735
  98%    767
  99%    768
 100%    768 (longest request)

结论是

1. View 里的循环多花了很多时间
2. 他的电脑没我的快

#26 楼 @QueXuQ 我就普通毕业的。因为没想好要做什么，毕业就在家想了半年。

用系统的 https://github.com/javan/whenever

#22 楼 @DoIT 写代码，思考人生。

#15 楼 @QueXuQ 毕业后家里蹲了半年。

我是毕业半年后才找工作，没提三方协议。

#11 楼 @QueXuQ 这真诡异了，production 和 development 是用同样的数据库吗？database.yml 里面有设置编码的项，数据库也有几个编码设置，都统一 utf-8。

#9 楼 @QueXuQ 顺着 javascript 的 link 看能不能打开，在控制台调用 js 里定义的 function 看能不能调用。

还有一个可能是浏览器缓存，chrome 的控制台右下角配置里面有 disable cache 选项。