Book Image

Apache Hive Essentials. - Second Edition

By : Dayong Du
Book Image

Apache Hive Essentials. - Second Edition

By: Dayong Du

Overview of this book

In this book, we prepare you for your journey into big data by frstly introducing you to backgrounds in the big data domain, alongwith the process of setting up and getting familiar with your Hive working environment. Next, the book guides you through discovering and transforming the values of big data with the help of examples. It also hones your skills in using the Hive language in an effcient manner. Toward the end, the book focuses on advanced topics, such as performance, security, and extensions in Hive, which will guide you on exciting adventures on this worthwhile big data journey. By the end of the book, you will be familiar with Hive and able to work effeciently to find solutions to big data problems
Table of Contents (12 chapters)

Performance utilities

HQL provides the EXPLAIN and ANALYZE statements, which can be used as utilities to check and identify the performance of queries. In addition, Hive logs contain enough detailed information for performance investigation and troubleshooting.

EXPLAIN statement

Hive provides an EXPLAIN statement to return a query execution plan without running the query. We can use it to analyze queries if we have concerns about their performance. The EXPLAIN statement helps us to see the difference between two or more queries for the same purpose. The syntax for it is as follows:

EXPLAIN [FORMATTED|EXTENDED|DEPENDENCY|AUTHORIZATION] hql_query

The following keywords can be used:

  • FORMATTED: This provides a formatted JSON...