In-the-clickstream queries on live data

We all know that you can implement different database queries--such as the preceding example--in different kinds of database management systems. However, in most alternative systems, these types of queries would yield terrible performance on the live database management systems and potentially endanger the responsiveness of an entire application. The reaction of the relational database management industry, therefore, has been to make sure that these kinds of queries will be done on precalculated, preformatted data that will be specifically structured for this purpose.

This means duplicating data, denormalizing data, and using techniques such as Extract, Transform, and Load (ETL), that are often used in business intelligence systems to create query-specific representations (sometimes also referred to as cubes) for the data at hand. Obviously, these are valuable techniques--the business intelligence industry would not be the billion-dollar industry that it is otherwise--but they are best suited for working with data that can be allowed to be more stale, less than up-to-date. Graph databases will allow you to answer a wider variety of these complex queries, between a web request and web response, on data that will not have to be replicated as much and therefore will be updated in near real time.