Apache Accumulo

The Apache Accumulo™ sorted, distributed key/value store is a robust, scalable, high performance data storage and retrieval system. Apache Accumulo is based on Google's BigTable design and is built on top of Apache Hadoop, Zookeeper, and Thrift. Apache Accumulo features a few novel improvements on the BigTable design in the form of cell-based access control and a server-side programming mechanism that can modify key/value pairs at various points in the data management process. Other notable improvements and feature are outlined here.

To install and run an Accumulo binary distribution, follow the install instructions.

Documentation

Accumulo provides the following documentation :

• User Manual : In-depth developer and administrator documentation.
• Examples : Code with corresponding readme files that give step by step instructions for running example code.

This documentation is available on the Accumulo site. In the source and binary distributions of Accumulo, the documentation is at different locations.

In the Accumulo binary distribution, all documentation is in the docs directory. The binary distribution does not include example source code, but it does include a jar with the compiled examples. This examples jar makes it easy to step through the example readmes, after following the install instructions.

In the Accumulo source, documentations is found at the following locations.

• Example Source
• Example Readmes
• User Manual Source

Building

Accumulo uses Maven to compile, test, and package its source. The following command will build the binary tar.gz from source. Note, these instructions will not work for the Accumulo binary distribution as it does not include source.

mvn package -P assemble

This command produces a file at the following location.

assemble/target/accumulo-X.Y.Z-SNAPSHOT-bin.tar.gz

This will not include documentation, adding the -P docs option to the maven command will build documentation.

API

The public Accumulo API is composed of :

All public types in the following packages and their subpackages excluding those named impl, thrift, or crypto.

• org.apache.accumulo.core.client
• org.apache.accumulo.core.data
• org.apache.accumulo.core.security
• org.apache.accumulo.minicluster

A type is a class, interface, or enum. Anything with public or protected acccess in an API type is in the API. This includes, but is not limited to: methods, members classes, interfaces, and enums. Package-private types in the above packages are not considered public API.

The following regex matches imports that are not Accumulo public API. This regex can be used with RegexpSingleline to automatically find suspicious imports in a project using Accumulo.

import\s+org\.apache\.accumulo\.(.*\.(impl|thrift|crypto)\..*|(?!core|minicluster).*|core\.(?!client|data|security).*)

The Accumulo project maintains binary compatibility across this API within a major release, as defined in the Java Language Specification 3rd ed. Starting with Accumulo 1.6.2 and 1.7.0 all API changes will follow semver 2.0