Book Image

Learning Apache Cassandra - Second Edition

Book Image

Learning Apache Cassandra - Second Edition

Overview of this book

Cassandra is a distributed database that stands out thanks to its robust feature set and intuitive interface, while providing high availability and scalability of a distributed data store. This book will introduce you to the rich feature set offered by Cassandra, and empower you to create and manage a highly scalable, performant and fault-tolerant database layer. The book starts by explaining the new features implemented in Cassandra 3.x and get you set up with Cassandra. Then you’ll walk through data modeling in Cassandra and the rich feature set available to design a flexible schema. Next you’ll learn to create tables with composite partition keys, collections and user-defined types and get to know different methods to avoid denormalization of data. You will then proceed to create user-defined functions and aggregates in Cassandra. Then, you will set up a multi node cluster and see how the dynamics of Cassandra change with it. Finally, you will implement some application-level optimizations using a Java client. By the end of this book, you'll be fully equipped to build powerful, scalable Cassandra database layers for your applications.
Table of Contents (14 chapters)

Recording aggregate analytics observations


When we explore precomputed aggregate data storage, let's focus on the first question posed earlier: how many total views did status updates receive on each day of September?

More generally, we want to store the daily overall view counts in a structure that allows us to easily retrieve the counts for a given range of time. We don't need to store discrete information about every view event that happened; simply knowing how many views occurred per day is sufficient.

Let's create a new daily_status_update_views table that aggregates our analytics observations at just the right granularity:

CREATE TABLE "daily_status_update_views" ( 
  "year" int, 
  "date" timestamp, 
  "total_views" counter, 
  "web_views" counter, 
  "mobile_views" counter, 
  "api_views" counter, 
  PRIMARY KEY (("year"), "date") 
); 

Of course, the most striking thing about this table definition is the introduction of the counter column type; we'll dive into this a little later in...