How Google is delivering performance

September 29, 2016

It’s no coincidence that the most successful search engine on the planet is also the fastest to return results. Here are some time charts from HttpWatch for Google and its two closest competitors are Yahoo.com and Live.com (i.e., Bing.com),
1. Google.com returns its results page in 0.155 seconds.
2. Live.com returns its results page in 0.619 seconds:
3. Yahoo returns its results page in 1.131 seconds:
After clicking the ‘Search’ button, the results of the keyword search are delivered by Google approximately four times faster than Live.com and seven times faster than Yahoo. Reason behind this faster responses are,
1. Clearly, the time taken to lookup the results for a keyword is because of Google’s distributed super-computer reputedly running on a cluster of one hundred thousand servers is at the heart of that. However, Google has also optimized the results page by applying two of the most important aspects of web site performance tuning:
  - Make less HTTP requests
  - Minimized the size of the downloaded data
2. The Google results page requires only one network round-trip compared to the four and eight round-trips required by Live.com and Yahoo respectively. They have achieved this by ensuring that the results page has no external dependencies. All its “style” information and “JavaScript” code has been in-lined with<style> and <script> tags.
3. This is because the results page uses a technique called CSS Sprites. All the images used on the results page are carefully sliced out of this single aggregate image with the CSS background-position attribute. The use of this technique has allowed Google to load the search page images in a single round-trip.
Major advantage of the Google results page, over its competitors, is the amount of data that is downloaded. You can see this by looking at the highlighted values in the HttpWatch page summaries:
1. The Google results page only requires 6 KB of data to be downloaded, whereas Live.com requires 16 KB and 57 KB for Yahoo. All three search engines use HTTP compression, but Google’s results page requires less data because:
  - Their page is simpler so it requires less HTML.
  - They have avoided extra round-trips for script and CSS. Each round trip requires HTTP response headers and adds to the total amount of data that has to be downloaded. In addition, HTTP compression tends to be more efficient on a single large request rather than several smaller requests.
  - The HTML is written to minimize size at the expense of readability. It contains very little white space, no comments and uses short variable names and ids.
2. Not only do these techniques improve the performance of the Google results page, but also they have the added benefit of reducing the load on the Google web servers.