Architecting HBase Applications

Chapter 2. HBase Principles

In the previous chapter, we provided a general HBase overview, and we will now go into more detail and look at HBase principles and internals. Although it is very important to understand HBase principles in order to create a good design, it is not mandatory to know all of the internals in detail. In this chapter, we will focus the discussion on describing those HBase internals that will steer you toward good design decisions.

Table Format

Like traditional databases, HBase stores data in tables and has the concept of row keys and column names. Unlike traditional databases, HBase introduces the concept of column families, which we will describe later. But compared to RDBMSs, while the nomenclature is the same, tables and columns do not work the same way in HBase. If you’re accustomed to traditional RDBMSs, most of this might seem very familiar, but because of the way it is implemented, you will need to hang up your legacy database knowledge and put your preconceptions aside while learning about HBase.

In HBase, you will find two different types of tables: the system tables and the user tables. Systems tables are used internally by HBase to keep track of meta information like the table’s access control lists (ACLs), metadata for the tables and regions, namespaces, and so on. There should be no need for you to look at those tables. User tables are what you will create for your use cases. They will belong to the default namespace unless you create and use ...