# \[ANN\] memcache-client extensions plugin **URL:** \ **Category:** Rails\ **Created:** [November 7, 2006, 10:53am UTC](https://www.ruby-forum.com/t/ann-memcache-client-extensions-plugin/74718 "2006-11-07T10:53:42Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![casper\_the\_ghost](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/58956e/32.png) [@casper\_the\_ghost](https://www.ruby-forum.com/u/casper_the_ghost)\ **Post date:** [November 7, 2006, 10:53am UTC](https://www.ruby-forum.com/t/ann-memcache-client-extensions-plugin/74718/1 "2006-11-07T10:53:42Z")
From: [http://blog.zvents.com/2006/11/1/rails-plugin-memcacheclient-extensions](http://blog.zvents.com/2006/11/1/rails-plugin-memcacheclient-extensions) =MemCacheClient Extensions == About The memcache-client\_extensions plugins adds three new commands to the memcache client API: 1. get\_multi : retrieve more than 1 key in parallel 2. stats : retrieve server performance and utilization statistics 3. flush\_all : empty all information stored in memcached == Installation 1. This plugin requires that the memcache-client gem is installed. 2. Install the plugin or the gem $ script/plugin install svn://rubyforge.org/var/svn/zventstools/projects/memcache-client\_extensions - OR - # gem install memcache-client\_extensions == get\_multi Retrieve multiple values from memcached in parallel, if possible. The memcached protocol supports the ability to retrieve multiple keys in a single request. Pass in an array of keys to this method and it will: a. map the key to the appropriate memcached server b. send a single request to each server that has one or more key values Returns a hash of values. > > CACHE[“a”] = 1 > > =\> 1 > > CACHE[“b”] = 2 > > =\> 2 > > CACHE.get\_multi([“a”,“b”]) > > =\> {“a”=\>1, “b”=\>2} Here’s a benchmark showing the speedup: CACHE[“a”] = 1 CACHE[“b”] = 2 CACHE[“c”] = 3 CACHE[“d”] = 4 keys = [“a”,“b”,“c”,“d”,“e”] Benchmark.bm do |x| x.report { for i in 1…1000; keys.each{|k| CACHE.get(k);} end } x.report { for i in 1…1000; CACHE.get\_multi(keys); end } end returns: user system total real 0.180000 0.130000 0.310000 ( 0.459418) 0.200000 0.030000 0.230000 ( 0.269632) There’s a fair amount of non-DRY between get\_multi and get (and threadsafe\_cache\_get/multi\_threadsafe\_cache\_get and cache\_get/multi\_cache\_get for that matter) but I think it’s worth it since the extra overhead to handle multiple return values is unneeded for a single-key get (which is by far the most common case). == stats The stats method returns statistics for each memcached server. An explanation of the statistics can be found in the memcached docs: [http://cvs.danga.com/browse.cgi/wcmtools/memcached/doc/protocol.txt?rev=HEAD&content-type=text/plain](http://cvs.danga.com/browse.cgi/wcmtools/memcached/doc/protocol.txt?rev=HEAD&content-type=text/plain) Example: > > CACHE.stats > > =\> {“localhost:11211”=\>{“pid”=\>“20188”, “bytes”=\>“4718”, > > “connection\_structures”=\>“4”, “time”=\>“1162278121”, > > “pointer\_size”=\>“32”, “limit\_maxbytes”=\>“67108864”, “version”=\>“1.2.0”, > > “cmd\_get”=\>“14532”, “cmd\_set”=\>“32”, “bytes\_written”=\>“432583”, > > “uptime”=\>“1557”, “curr\_items”=\>“4”, “curr\_connections”=\>“3”, > > “total\_connections”=\>“19”, “get\_misses”=\>“0”, > > “rusage\_user”=\>“0.119981”, “rusage\_system”=\>“0.313952”, > > “total\_items”=\>“32”, “get\_hits”=\>“14532”, “bytes\_read”=\>“190619”}} == flush\_all The flush\_all method empties all cache namespaces on all memcached servers. This method is very useful for testing your code with memcached since you normally want to reset the cache to a known (empty) state at the beginning of each test. == Bugs, Code and Contributing There’s a RubyForge project set up at: [http://rubyforge.org/projects/zventstools/](http://rubyforge.org/projects/zventstools/) Anonymous SVN access: $ svn checkout svn://rubyforge.org/var/svn/zventstools Author: Tyler K. (tyler dot kovacs at gmail dot com) ---
**Author:** ![casper\_the\_ghost](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/58956e/32.png) [@casper\_the\_ghost](https://www.ruby-forum.com/u/casper_the_ghost)\ **Post date:** [November 7, 2006, 11:00am UTC](https://www.ruby-forum.com/t/ann-memcache-client-extensions-plugin/74718/2 "2006-11-07T11:00:44Z")
Cool 🙂 Slightly OT here, but is there a way to access all values from a namespace in memcached? Like “get all my books” or something. Seems like a good extension to your get\_multi function. But perhaps the memcached protocol doesn’t allow for this. That was my finding the last time I read through it. Somebody should fix this though: clearing/adding-to/retrieving a namespace is a real good feature to add. Vish ---
**Author:** ![casper\_the\_ghost](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/58956e/32.png) [@casper\_the\_ghost](https://www.ruby-forum.com/u/casper_the_ghost)\ **Post date:** [November 7, 2006, 11:04am UTC](https://www.ruby-forum.com/t/ann-memcache-client-extensions-plugin/74718/3 "2006-11-07T11:04:45Z")
No, the memcached protocol doesn’t support a “get all” method. Here’s a thread from the memcached mailing that covers the issue: [http://lists.danga.com/pipermail/memcached/2006-April/002112.html](http://lists.danga.com/pipermail/memcached/2006-April/002112.html) You could memcache your dataset in an array (in addition to memcaching each individual item for single-item retrieval), but that probably wouldn’t be a good idea for anything other than very small datasets.