Heroku/Memcache/Rack::缓存统计

Question

我正试图围绕 Rack::Cache、Rails 3.2、Memcache 和 Heroku。我想我已经把这一切一起工作了，如下所述：http://myownpirateradio.com/2012/01/01/getting-heroku-cedar-and-rails-3-1-asset-pipeline-to-play-nicely-together/

说了这么多，我不确定 Memcached 是否真的在做它应该做的事情。有什么方法可以获取 Memcached 的统计信息或查看 Memcached 是否缓存了请求？我将当前时间放在页面上，并且可以看到它正在被缓存（标题看起来也不错），但我怎么知道它全部使用 Memcached，而不是文件存储？

谢谢。

Answer 1

您可以通过以下方式获取 memcached 的统计信息：

$ heroku run console
Running console attached to terminal... up, run.1
Loading production environment (Rails 3.1.3)
irb(main):001:0> Rails.cache.stats
Dalli/SASL authenticating as app590983%40heroku.com
Dalli/SASL: Authenticated
=> {"mc5.ec2.northscale.net:11211"=>{"evictions"=>"0", "curr_items"=>"627",
    "total_items"=>"1257", "bytes"=>"2294318", "reclaimed"=>"0", 
    "engine_maxbytes"=>"5242880", "bucket_conns"=>"2", "pid"=>"319", 
    "uptime"=>"6710022", "time"=>"1330731177", "version"=>"1.4.4_207_g19c6b9e", 
    "libevent"=>"1.4.11-stable", "pointer_size"=>"64", 
    "rusage_user"=>"34354.590000", "rusage_system"=>"31381.520000", 
    "daemon_connections"=>"10", "curr_connections"=>"1211", 
    "total_connections"=>"14127919", "connection_structures"=>"1764", 
    "cmd_get"=>"9476", "cmd_set"=>"1257", "cmd_flush"=>"0", "auth_cmds"=>"24", 
    "auth_errors"=>"0", "get_hits"=>"8093", "get_misses"=>"1383", 
    "delete_misses"=>"0", "delete_hits"=>"0", "incr_misses"=>"0", 
    "incr_hits"=>"0", "decr_misses"=>"0", "decr_hits"=>"0", "cas_misses"=>"0", 
    "cas_hits"=>"0", "cas_badval"=>"0", "bytes_read"=>"21983909", 
    "bytes_written"=>"85267718", "limit_maxbytes"=>"67108864", 
    "rejected_conns"=>"0", "threads"=>"4", "conn_yields"=>"0"}}

PS：我认为您可能需要使用 Dalli gem 才能使其工作，但无论如何这是推荐的客户端。

您也可以运行 Rails.cache.class 来查看 Rails 使用的是哪个后端。