Designing Data-Intensive Applications: The Big Ideas Behind Reliable, Scalable, and Maintainable Systems

by Martin Kleppmann

For example, if you have an application-managed caching layer (using Memcached or similar), or a full-text search server (such as Elasticsearch or Solr) separate from your main database, it is normally the application code’s responsibility to keep those caches and indexes in sync with the main database. Figure 1-1 gives a glimpse of what this may look like (we will go into detail in later chapters).

This is a great example. Youre thinking "everyone needs to do this! Let's solve it once and for all!" If everyone needs to do this, and it was easy, it would exist. You don't understand the problem yet... I remember when I was young and full of hope. I miss hope. Hope was fun.