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Transforming Data within Hive

Transforming Data within Hive

Jan 27, 2012

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How to read data from a Hive table, transform it, and write it to a Hive table within the workflow of a PDI job.

Prerequisites

In order follow along with this how-to guide you will need the following:

  • Hadoop

  • Pentaho Data Integration

  • Hive

Sample Files

The source data for this guide will reside in a Hive table called weblogs. If you have previously completed the Loading Data into Hive guide, then you can skip to #Create a Database Connection to Hive. If not, then you will need the following datafile and perform the #Create a Hive Table instructions before proceeding.
The sample data file needed for the #Create a Hive Table instructions is:

File Name

Content

Tab-delimited, parsed weblog data

NOTE: If you have previously completed the Using Pentaho MapReduce to Parse Weblog Data guide, then the necessary files will already be in the proper location.
This file should be placed in the /weblogs/parse directory of the CLDB using the following commands.

hadoop fs -mkdir /weblogs hadoop fs -mkdir /weblogs/parse hadoop fs -put weblogs_parse.txt /weblogs/parse/part-00000

 

Step-By-Step Instructions

Setup

Start Hadoop if it is not already running.
Start Hive Server if it is not already running.