Caching and Its Main Types

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Caching and Its Main Types
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Table of Contents

• Introduction
• Caching
• Web Browser
• Web Browser Caches Function
• Clearing a Browser Cache
• Major Types of Caching

• Web Caching (Browser/Proxy/Gateway)
• Data Caching
• Application/Output Caching
• Distributed Caching
• Conclusion

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Introduction

• The content of this PPT is meant for providing
  information on the process of caching and its
  different types. Despite having encountered the
  term caching frequently, many are unaware of
  what it entails.
• The information contained in this PPT will prove
  to be useful for understanding the concept of
  caching.

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Caching

• The process of caching involves storage of files
  copies in a cache or in a temporary location for
  storage. This is meant for accessing the files
  more quickly. Usually, a cache indicates a
  storage location that is temporary in nature and
  is meant for data or copies of files.
• Some examples are-
• Web browsers which cache JavaScript, images and
  HTML files for the purpose of loading websites
  quickly.
• DNS servers which cache DNS records to ensure
  faster lookups.
• CDN servers cache content to ensure reduction in
  latency.

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Web Browser

• A web browser, which is commonly known as a
  browser, is essentially an application software
  that serves the function of accessing the World
  Wide Web. The use of web browsers happens on a
  range of devices, which includes laptops,
  smartphones, tablets, desktops, etc.
• Every user of the Internet needs to have a web
  browser installed in his device in order to
  connect to the server of a website and to display
  the web pages of that website. The contents of
  websites are stored in the form of files on the
  web servers of web hosting companies and are
  processed on it and delivered from there to the
  web browsers. Whenever a user looks for a certain
  web page on the Internet, the web browser
  retrieves its contents from the corresponding web
  server and displays the web page on the device of
  the user.
• Web hosting service providers that provide
  excellent web hosting services are often referred
  to as the Best Web Hosting Company, the Best
  Cloud Hosting Company, the Best Windows Hosting
  Company, etc.

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Web Browser Caches Function

• Each time that a web page loads onto a users
  device, the web browser has to download a huge
  volume of data for the purpose of displaying the
  web pages. When browsers cache most of the
  content of the webpage, it shortens page load
  times by saving a copy of the content of the web
  page on the hard drive of the device of the user.
  The next time that the user visits the same web
  page and its contents get loaded onto the users
  device, the page loads comparatively faster, as
  most of the sites contents are already stored
  locally.
• These files are stored on the browsers till their
  TTL expires or until the cache of the hard drive
  is full, whichever happens earlier. TTL refers to
  Time to Live and indicates the duration for which
  content needs to be cached. It is also possible
  for users to clear their browser cache.

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1-800-123 -8156

• Whoa! Thats a big number, arent you
  proud?

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Clearing a Browser Cache

• The result of deliberately clearing a browser
  cache by a user is that web pages, despite being
  revisited, would load in a way as if those were
  loading for the first time. The advantage with
  regard to faster web page loading would cease to
  exist.
• One advantage of clearing a browser cache is that
  if any web content didnt load correctly the
  first time and was cached, it might load
  correctly on clearing the cache. The biggest
  disadvantage of clearing the browser cache
  reflects in slow page load times.

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Major Types of Caching

• Web development and web hosting typically entails
  four main types of caching. These are as follows-
• Web Caching (Browser/Proxy/Gateway)
• Data Caching
• Application/Output Caching
• Distributed Caching
• Next, each of these four types of caching will be
  elaborated on, individually.

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Web Caching (Browser/Proxy/Gateway)

• Although Browser, Gateway and Proxy caching work
  in different ways these cater to the same goal
  of reducing overall network traffic and latency.
  Browser caching is controlled at the individual
  user level. On the other hand, proxy and gateway
  are on a much larger scale. The latter, proxy and
  gateway, enable the sharing of cached information
  across larger groups of users. Usually, cached
  data can be DNS (Domain Name Server) data, which
  is used for resolving domain names to IP
  addresses and mail server records. This data type
  doesnt change frequently and can be cached for a
  long duration by the Proxy and/or Gateway
  servers.
• Browser caching enables faster navigation with
  regard to the web pages that have been visited
  recently. This caching feature, which is free, is
  often overlooked by most hosting companies and
  developers. The presence of Cache-Control and
  ETag headers is required by this process, for
  instructing the browser of the user to cache
  certain files for a certain duration of time.

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Data Caching

• Database driven applications as well as CMS
  solutions reap the benefits of data caching. This
  type of caching serves well for frequent calls to
  data, which dont alter rapidly. Data caching
  enhances user experience by ensuring that
  websites and applications load faster. This is
  attained by cutting down on extra visits to the
  DB for retrieving data sets which are known to
  have not changed. Data are stored on the servers
  local memory and provide the fastest route for
  retrieval of information on a web server. The
  less the number of DB calls, the better it is.
  Usually attempts are made by most of the DB
  solutions to cache those queries that are
  frequently used. This is done to ensure reduction
  in turnaround time.
• Standard practice calls for clearing of any cache
  data post data alteration. This ensures that the
  front-end of CMS always has the most recent data
  and prevents it from hitting the database for
  each user that hits a page. Memory issues can
  result from the overuse of data caching, due to
  constant addition and removal of data to and from
  cache.

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Application/Output Caching

• Application/Output Caching ensures a drastic
  reduction in website load times as well as
  reduces server overhead. This type of caching
  differs from data caching, wherein raw data sets
  are stored. Server level caching techniques,
  which cache raw HTML, are often utilized in
  application/output caching. It delivers page load
  times that are almost 50 faster.

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Distributed Caching

• Distributed Caching enables web servers to pull
  and store from the memory of distributed servers.
  It is used by most of the high-volume systems,
  such as Amazon, YouTube, etc. Post
  implementation, it enables the web server to
  serve web pages without having to face any issue
  with regard to running out of memory. In it, the
  distributed cache is made of a cluster of
  machines that serve memory. A new machine of
  memory can be added at any time when the cluster
  has been set up and this can be done without
  causing any issue to existing users. Distributed
  caching provides a powerful solution once it is
  deployed. Memcached for Linux and AppFabric for
  Windows Server are some of the well-known
  systems.

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Conclusion

• Web caching aids substantially in speeding up
  loading times. Web caches can be of many
  different types. Each of the different web caches
  proves to be useful in a different set of
  circumstances. Hence, it is important to not only
  understand the types of cache that are available
  but also the levels of control that these offer
  to end-users.

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