How to use Memcached in Rails applications

What is Memcached?

Memcached is a technology used as a system for storing and distributing data in server memory (RAM). Detik.com is an example of a website using Memcached. The very fast search engine is coded with memcached. The working of memcached is very simple because its function is only to cache the server and reduce the load on the database server and the data stored by memcached is stored in memory so that accessing the data is much faster than accessing the database server.

Install Memcached on Ubuntu

Update package

Then install Memcached and associated packages

$ sudo apt-get install memcached

Setting up Memcached installation

Use the following command to display information about the memcached command:

The default configuration file can be found at:

$ vi /etc/memcached.conf

On startup, Memcached will start on port 11211 by default according to the default configuration file. To change the port, simply change the number in the configuration file. If you want to run Memcached on the port 1337with memory 4GBand allows a maximum 2,000 connection, change it to the following code:

-p 1337
-m 4096
-c 2000 

Exit and save the configuration file, then restart Memcached

$ sudo service memcached restart

Implementation of MMR

Start from scratch and create a new project

$ rails new memcached_coba -d postgresql

$ cd memcached_coba

$ rails g scaffold post title:string description:text

$ rake db:create

$ rake db:migrate

Start configuring Memcache


Add the ‘dalli’ gem to the Gemfile and then do the bulk install

Edit file config/environments/development.rb add or modify:

    config.cache_store = :dalli_store

Create a file ‘memcached.rb‘ on file config/initializers/memcached.rb contents of the file as follows:

CACHE = Dalli::Client.new('127.0.0.1', { :namespace => 'memcached_coba', :expires_in => 3600, :socket_timeout => 3, :compress => true })

Basics of using Memcached


# Memcached backup

 CACHE.set(key, value)

# Set timeout

 CACHE.set(key, value, time_expire)

# Using Memcached

 CACHE.get(key, value)

# Remove Memcached

 CACHE.delete(key)

# Delete all memcached

 CACHE.flush_all

The following is a screenshot of the results of my experiments in the Rails console:

Next, we will try to save the post data using Memcached


Before using Memcached, publish the data first


Let’s look at the server logs Before Using Memcached and the following screenshot

Image Before using Memcached

Now we install Memcached in the posts details


Ubah code method set_post pada file app/controllers/posts_controller.rb

    def set_post
      @post = CACHE.get("post-#{params[:id]}")
      if @post.nil?
         @post = Post.find(params[:id])
         CACHE.set("post-#{params[:id]}", @post)
       end
    end

Let’s look at the server logsAfter Using Memcached and the following screenshot

Image after using Memcached

From the above two images we can see the difference when using them memcached when you navigate to the post details page for the second time, the server does not load the database, as evidenced by the absence of the “load info” linePost Load (2.4 ms) SELECT “posts”.* FROM “posts” ‘

Using Memcached can make our website faster. That’s it for this article, if anyone has any questions or something is missing please comment below.