Apache Accumulo Examples

Introduction

The Accumulo-Examples repository contains a collection of examples for Accumulo versions 2.0 and greater. Examples within the main branch are designed to work with the version currently under development. Additional branches exist for previous releases of the Accumulo 2.x line. For example, the 2.0 branch contains examples specifically intended to work with that release version.

The Accumulo Tour also provides several simple introductory examples that may be of interest.

A collection of examples for Accumulo 1.10 can be found here.

Setup instructions

Follow the steps below to run the Accumulo examples:

1. Clone this repository

    git clone https://github.com/apache/accumulo-examples.git

2. Follow Accumulo’s quickstart to install and run an Accumulo instance. Accumulo has an accumulo-client.properties in conf/ that must be configured as the examples will use this file to connect to your instance.

3. Review env.sh.example and accumulo-env.sh (within your accumulo installation) to see if you need to customize them. If ACCUMULO_HOME & HADOOP_HOME are set in your shell, you may be able skip this step. Make sure ACCUMULO_CLIENT_PROPS is set to the location of your accumulo-client.properties.

    cp conf/env.sh.example conf/env.sh
    vim conf/env.sh

4. Build the examples repo and copy the examples jar to Accumulo’s lib/ directory to get on its class path:

    ./bin/build
    cp target/accumulo-examples.jar /path/to/accumulo/lib/

5. Each Accumulo example has its own documentation and instructions for running the example which are linked to below.

When running the examples, remember the tips below:

• Examples are run using the runex or runmr commands which are located in the bin/ directory of this repo. The runex command is a simple script that use the examples shaded jar to run a a class. The runmr starts a MapReduce job in YARN.
• Commands intended to be run in bash are prefixed by ‘$’ and should be run from the root of this repository.
• Several examples use the accumulo and accumulo-util commands which are expected to be on your PATH. These commands are found in the bin/ directory of your Accumulo installation.
• Commands intended to be run in the Accumulo shell are prefixed by ‘>’.

Available Examples

Each example below highlights a feature of Apache Accumulo.

Example	Description
batch	Using the batch writer and batch scanner
bloom	Creating a bloom filter enabled table to increase query performance
bulkIngest	Ingesting bulk data using map/reduce jobs on Hadoop
classpath	Using per-table classpaths
client	Using table operations, reading and writing data in Java.
combiner	Using example StatsCombiner to find min, max, sum, and count.
compactionStrategy	Configuring a compaction strategy
constraints	Using constraints with tables. Limit the mutation size to avoid running out of memory
deleteKeyValuePair	Deleting a key/value pair and verifying the deletion in RFile.
dirlist	Storing filesystem information.
export	Exporting and importing tables.
filedata	Storing file data.
filter	Using the AgeOffFilter to remove records more than 30 seconds old.
helloworld	Inserting records both inside map/reduce jobs and outside. And reading records between two rows.
isolation	Using the isolated scanner to ensure partial changes are not seen.
regex	Using MapReduce and Accumulo to find data using regular expressions.
reservations	Using conditional mutations to implement simple reservation system.
rgbalancer	Using a balancer to spread groups of tablets within a table evenly
rowhash	Using MapReduce to read a table and write to a new column in the same table.
sample	Building and using sample data in Accumulo.
shard	Using the intersecting iterator with a term index partitioned by document.
spark	Using Accumulo as input and output for Apache Spark jobs
tabletofile	Using MapReduce to read a table and write one of its columns to a file in HDFS.
terasort	Generating random data and sorting it using Accumulo.
tracing	Generating trace data in a client application and Accumulo.
uniquecols	Use MapReduce to count unique columns in Accumulo
visibility	Using visibilities (or combinations of authorizations). Also shows user permissions.
wordcount	Use MapReduce and Accumulo to do a word count on text files

Release Testing

This repository can be used to test Accumulo release candidates. See docs/release-testing.md.