Book Image

HBase Essentials

By : Nishant Garg
Book Image

HBase Essentials

By: Nishant Garg

Overview of this book

Table of Contents (14 chapters)

Understanding keys


In HBase, we primarily have the following keys to handle data within the tables:

  • Row Key: This provides a logical representation of an entire row, containing all the column families and column qualifiers

  • Column Key: This is formed by combining the column family and the column qualifier

Logically, the data stored in cells is arranged in a tabular format, but physically, these tabular rows are stored as linear sets of the actual cells. These linear sets of cells contain all the real data inside them.

Additionally, the data within multiple versions of the same cell is also stored as a separate linear set of cells and a timestamp is added, along with the cell data stored. These linear sets of cells are sorted in descending order by their timestamp so that the HBase client always fetches the most recent value of the cell data.

The following diagram represents how data is stored physically on the disk:

In HBase, the entire cell, along with the added structural information such as...