Cloudera Developer Blog · Hive Posts

How Impala Brings Real-Time, Big Data Analytics to Digital Reasoning’s Users

The following post, by Sarah Cannon of Digital Reasoning, was originally published in that company’s blog. Digital Reasoning has graciously permitted us to re-publish here for your convenience.

At the beginning of each release cycle, engineers at Digital Reasoning are given time to explore the latest in Big Data technologies, examining how the frequently changing landscape might be best adapted to serve our mission. As we sat down in the early stages of planning for Synthesys 3.8 one of the biggest issues we faced involved reconciling the tradeoff between flexibility and performance. How can users quickly and easily retrieve knowledge from Synthesys without being tied to one strict data model?

How-to: Use Parquet with Impala, Hive, Pig, and MapReduce

The CDH software stack lets you use your tool of choice with the Parquet file format – - offering the benefits of columnar storage at each phase of data processing. 

An open source project co-founded by Twitter and Cloudera, Parquet was designed from the ground up as a state-of-the-art, general-purpose, columnar file format for the Apache Hadoop ecosystem. In particular, Parquet has several features that make it highly suited to use with Cloudera Impala for data warehouse-style operations:

How-to: Implement Role-based Security in Impala using Apache Sentry

This quick demo illustrates how easy it is to implement role-based access and control in Impala using Sentry.

Apache Sentry (incubating) is the Apache Hadoop ecosystem tool for role-based access control (RBAC). In this how-to, I will demonstrate how to implement Sentry for RBAC in Impala. I feel this introduction is best motivated by a use case.

Native Parquet Support Comes to Apache Hive

Bringing Parquet support to Hive was a community effort that deserves congratulations!

Previously, this blog introduced Parquet, an efficient ecosystem-wide columnar storage format for Apache Hadoop. As discussed in that blog post, Parquet encodes data extremely efficiently and as described in Google’s original Dremel paper. (For more technical details on the Parquet format read Dremel made simple with Parquet, or go directly to the open and community-driven Parquet Format specification.)

Migrating from Hive CLI to Beeline: A Primer

Migrating from the Hive CLI to Beeline isn’t as simple as changing the executable name, but this post makes it easy nonetheless.

In its original form, Apache Hive was a heavyweight command-line tool that accepted queries and executed them utilizing MapReduce. Later, the tool split into a client-server model, in which HiveServer1 is the server (responsible for compiling and monitoring MapReduce jobs) and Hive CLI is the command-line interface (sends SQL to the server).

How-to: Get Started Writing Impala UDFs

Cloudera provides docs and a sample build environment to help you get easily started writing your own Impala UDFs.

User-defined functions (UDFs) let you code your own application logic for processing column values during a Cloudera Impala query. For example, a UDF could perform calculations using an external math library, combine several column values into one, do geospatial calculations, or other kinds of tests and transformations that are outside the scope of the built-in SQL operators and functions.

Impala Performance Update: Now Reaching DBMS-Class Speed

Impala’s speed now beats the fastest SQL-on-Hadoop alternatives. Test for yourself!

Since the initial beta release of Cloudera Impala more than one year ago (October 2012), we’ve been committed to regularly updating you about its evolution into the standard for running interactive SQL queries across data in Apache Hadoop and Hadoop-based enterprise data hubs. To briefly recap where we are today:

How-to: Get Started with Sentry in Hive

A quick on-ramp (and demo) for using the new Sentry module for RBAC in conjunction with Hive

One attribute of the Enterprise Data Hub is fine-grained access to data by users and apps. This post about supporting infrastructure for that goal was originally published at We republish it here for your convenience.

Explore the Impala App in Hue

The following post was originally published by the Hue Team at the Hue blog in a slightly different form.

Hue, the open source web GUI that makes Apache Hadoop easy to use, has supported Cloudera Impala since its inception to enable fast, interactive SQL queries from within your browser. In this post, you’ll see a demo of Hue’s Impala app in action and explore its impressive query speed for yourself.

Impala App Demo

Demo: Using Hue to Access Hive Data Through Pig

This installment of the Hue demo series is about accessing the Hive Metastore from Hue, as well as using HCatalog with Hue. (Hue, of course, is the open source Web UI that makes Apache Hadoop easier to use.) 

What is HCatalog?

HCatalog is a module in Apache Hive that enables non-Hive scripts to access Hive tables. You can then directly load tables with Apache Pig or MapReduce without having to worry about re-defining the input schemas, or caring about or duplicating the data’s location.

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