[Pig Wiki] Update of "owl" by jaytang

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The following page has been changed by jaytang:
http://wiki.apache.org/pig/owl

New page:
#format wiki
#language en
#pragma section-numbers off

= Apache Owl Wiki =

The goal of Owl (a.k.a Hadoop metadata system) is to allow users and applications to register data stored on HDFS, search for the data available on HDFS, and associate metadata such as schema, statistics, etc. with a particular data unit or a data set stored on HDFS. The initial goal is to provide a fairly generic, low level abstraction that any user or application on HDFS can use to store an retrieve metadata. Over time a higher level abstractions closely tied to particular applications or tools can be developed.

Please refer to this document for more detailed [http://wiki.apache.org/pig/Metadata use case, architecture, data model]


== Prerequisite ==

Owl high no dependency on the release of Hadoop and Pig

== Getting Owl ==

Owl has been committed as a Pig contrib project at:

[http://svn.apache.org/viewvc/hadoop/pig/trunk/contrib/owl Owl source code]

Compilation prerequisite:

   * JDK 1.6
   * Ant 1.7.1

How to compile

   * check out latest PIG trunk
   * cd contrib/owl
   * ant war (build owl web application)
   * ant test (run owl unit test using jetty and derby without any setup steps)

== Deploying Owl ==

For development environment, Owl supports jetty 7.0 (with jetty-runner) and derby 10.5.  For production deployment, Owl supports:

   * Tomcat 6.0
   * MySQL 5.1

After installing Tomcat and MySQL, you will need these files:

   * owl.war - owl web application
   * mysql_schema.sql - owl database schema file at contrib/owl/setup/mysql
   * owlServerConfig.xml - owl server configuration file at contrib/owl/setup/mysql


Set up parameters in owlServerConfig:

Create db schema in MySql:

Deploy Owl to Tomcat:


== Sample Code == 

Owl comes with a Java-based client.  Client API Javadoc is at: 

Sample code is attached to write a client application against owl: