Too Long; Didn't Read
It’s quite possible to get more out of an existing Postgres database. It can scale for heavy loads and offers powerful features which are not obvious at first sight. It's possible to enable in-memory caching, text search, specialized indexing, and key-value storage. Adding another data store like Redis or Elasticsearch is not always a good idea. Postgres has a beautifully designed caching system with pages, usage counts, and transaction logs. The shared_buffer configuration parameter determines how much memory it will use for caching data.