Book Image

Apache Hive Cookbook

Book Image

Apache Hive Cookbook

Overview of this book

Hive was developed by Facebook and later open sourced in Apache community. Hive provides SQL like interface to run queries on Big Data frameworks. Hive provides SQL like syntax also called as HiveQL that includes all SQL capabilities like analytical functions which are the need of the hour in today’s Big Data world. This book provides you easy installation steps with different types of metastores supported by Hive. This book has simple and easy to learn recipes for configuring Hive clients and services. You would also learn different Hive optimizations including Partitions and Bucketing. The book also covers the source code explanation of latest Hive version. Hive Query Language is being used by other frameworks including spark. Towards the end you will cover integration of Hive with these frameworks.
Table of Contents (19 chapters)
Apache Hive Cookbook
Credits
About the Authors
About the Reviewer
www.PacktPub.com
Preface
Index

Partitioning a managed table


Managed tables can be partitioned using the PARTITIONED BY clause. In a managed table, if you delete a table, then the data of that table will also get deleted. Similarly, if you delete a partition, then the data of that partition will also get deleted.

How to do it…

Let's take an example of the customer table data and imagine that we have the data of different customers of different country. Now if we don't enable any partitioning, then by default, all data will go into one directory. Let's assume that data size is around 1 TB. Now if we query for customers belonging to India, then this query will be executed on entire data of 1 TB size and this query will take more time. By enabling partitioning this query, execution can be much faster. If we want to split the data on the country basis, then the following command can be used to create a table with the partitioned column country:

CREATE TABLE customer(id STRING, name STRING, gender STRING, state STRING) PARTITIONED...