Over the course of recent years, websites have undergone a significant change. Many new services and social media websites have been created, mobile applications now play a very significant role on the internet, and various on-line services exchanging data is nothing out of the ordinary anymore. We could even say that integration with external services is standard now, especially in the case of large e-commerce applications or on-line payment systems.
Time has already passed since the premiere of Drupal 8. New projects and modules are released all the time, and there is an ever-increasing number of projects compatible with version 8.x at drupal.org. Sadly, these versions are often still unstable and filled with various bugs.
Drupal is a bit famous for the number of database queries done against a database. When there are thousands of concurrent users to be served, the database can quickly turn into a major bottleneck. This was the case with http://kwestiasmaku.com - a very popular website with recipes. The website is visited by millions of enthusiasts of cooking.