Introduction to Open Source Search with Apache Lucene and SolrGrant Ingersoll

Lucid Imagination, Inc.

The How Many Game

•How many of you:o Have taken a class in Information Retrieval (IR)?o Are doing work/research in IR?o Have heard of or are using Lucene?o Have heard of or are using Solr?o Are doing work on core IR algorithms such as compression

techniques or scoring?o Are doing UI/Application work/research as they relate to search?

Lucid Imagination, Inc.

Topics

•Brief Bio

•Search 101 (skip?)

•What is:o Apache Luceneo Apache Solr

•What can they do?o Features and functionalityo Intangibles

•What’s new in Lucene and Solr?o How can they help my research/work/____?

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Brief Bio

•Apache Lucene/Solr Committer

•Apache Mahout co-foundero Scalable Machine Learning

•Co-founder of Lucid Imaginationo http://www.lucidimagination.com

•Previously worked at Center for Natural Lang. Processing at Syracuse Univ. with Dr. Liddy

•Co-Author of upcoming “Taming Text” (Manning Publications)o http://www.manning.com/ingersoll

Lucid Imagination, Inc.

Search 101

•Search tools are designed for dealing with fuzzy data/questionso Works well with structured and unstructured data

o Performs well when dealing with large volumes of data

o Many apps don’t need the limits that databases place on contento Search fits well alongside a DB too

• Given a user’s information need, (query) find and, optionally, score content relevant to that needo Many different ways to solve

this problem, each with tradeoffs

•What’s “relevant” mean?

Vector Space Model (VSM) for relevanceCommon across many search enginesApache Lucene is a highly optimized implementation of the VSM

Search 101

Relevance IndexingFinds and maps terms and documents

Conceptually similar to a book index

At the heart of fast search/retrieve

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Apache Lucene in a Nutshell

•http://lucene.apache.org/java

•Java based Application Programming Interface (API) for adding search and indexing functionality to applications

•Fast and efficient scoring and indexing algorithms

•Lots of contributions to make common tasks easier:o Highlighting, spatial, Query Parsers, Benchmarking tools, etc.

•Most widely deployed search library on the planet

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Lucene Basics

•Content is modeled via Documents and Fieldso Content can be text, integers, floats, dates, customo Analysis can be employed to alter content before indexing

•Searches are supported through a wide range of Query optionso Keywordo Termso Phraseso Wildcardso Many, many more

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Apache Solr in a Nutshell

•http://lucene.apache.org/solr

•Lucene-based Search Server + other features and functionality

•Access Lucene over HTTP:o Java, XML, Ruby, Python, .NET, JSON, PHP, etc.

•Most programming tasks in Lucene are configuration tasks in Solr

•Faceting (guided navigation, filters, etc.)

•Replication and distributed search support

•Lucene Best Practices

A small sampling of Lucene/Solr-Powered Sites

10

Buy.com

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Features and Functionality

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Quick Solr/Lucene Demo•Pre-reqs:

o Apache Ant 1.7.x, Subversion (SVN)

•Command Line 1:o svn co https://svn.apache.org/repos/asf/lucene/dev/trunk solr-trunko cd solr-trunk/solr/o ant exampleo cd exampleo java –Dsolr.clustering.enabled=true –jar start.jar

•Command Line 2o cd exampledocs; java –jar post.jar *.xml

•http://localhost:8983/solr/browse?q=&debugQuery=true&annotateBrowse=true

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Other Features

•Data Import Handlero Database, Mail, RSS, etc.

•Rich document support via Apache Tikao PDF, MS Office, Images, etc.

•Replication for high query volume

•Distributed search for large indexeso Production systems with 1B+ documents

•Configurable Analysis chain and other extension pointso Total control over tokenization, stemming, etc.

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Intangibles

•Open Source

•Flexible, non-restrictive licenseo Apache License v2 – non-viralo “Do what you want with the software, just don’t claim you wrote

it”

•Large community willing to helpo Great place to learn about real world IR systems

•Many books and other documentationo Lucene in Action by Hatcher, McCandless and Gospodnetic

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What’s New?

•https://svn.apache.org/repos/asf/lucene/dev/trunk/lucene/CHANGES.txt

•https://svn.apache.org/repos/asf/lucene/dev/trunk/solr/CHANGES.txt

•Codecso Pluggable Index Formatso Provide Different index compression techniques

•Stats to enable alternate scoring approaches BM25, Lang. Modeling, etc. -- More work to be done here

•Fastero Java Strings are slow; convert to use byte arrays

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Other New Items

•Many new Analyzers (tokenizers, etc.)o Richer Language support (Hindi, Indonesian, Arabic, …)

•Richer Geospatial (Local) Search capabilitieso Score, filter, sort by distanceo http://wiki.apache.org/solr/SpatialSearch

•Results Groupingo Group Related Resultso http://wiki.apache.org/solr/FieldCollapsing

•More Faceting Capabilitieso Pivoto New underlying algorithms

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How can Lucene/Solr help me?

Everyone• Fast indexing/search times means less time

waiting for jobs to complete• Completely Open (source, community)• Free to use, modify, etc.• Large community ready and willing to help

User Experience Researchers• Rapid UI prototyping• Total Control of results and facets• Easy to setup and use with little to no

programming required

IR Researchers• Flexible Indexing models (trunk)• Flexible Relevance models via functions

and other mechanisms• Extendable

Job Seekers• Google Summer of Code• Other Internships (see me)• Real programming skills that are highly

valued in industry• Publicly visible, demonstrable skills

Lucene/Solr

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Job Trends

http://www.indeed.com

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Other Things that Can Help

•Nutcho Crawling

o http://nutch.apache.org

•Mahouto Machine learning (clustering, classification, others)

o http://mahout.apache.org

•OpenNLPo Part of Speech, Parsers, Named Entity Recognition

o http://incubator.apache.org/opennlp

•Open Relevance Projecto Relevance Judgments

o http://lucene.apache.org/openrelevance

Lucid Imagination, Inc.

Resources

•http://lucene.apache.org

•http://www.lucidimagination.com

•{java-user|solr-user}@lucene.apache.org

•@gsingers

•http://www.slideshare.net/gsingers

•grant@lucidimagination.com