eZ Find workshop: advanced insights & recipes

© 2013 Paul Borgermans, K-Minds Comm.V.
eZ Find Recipes & Insights
September 4
Bol, Croatia
Paul Borgermans

About me
l  12+ years in the eZ ecosystem
-  eZ Lucene → eZ Solr → eZ Find
l  Fancying :
-  Apache Lucene family of projects (mainly Solr)
-  NoSQL (Not only SQL) and scalable architectures
-  eZ Publish & CMS systems in general
-  Semantic aspects
-  PHPBenelux Community & Conference
l  Contact
paul.borgermans@gmail.com
@paulborgermans

Part 1: eZ Find Kitchen Basics
•  Get to know the ingredients & tools
•  Installation recipes
•  Basic configuration options
•  Basic indexing
•  Basic searching, filtering and facets

Get to know the ingredients &
tools
Powered by

eZ Find main search ingredients
l  Tunable relevancy ranking
l  Keyword highlighting
l  Filtering and Facets (drill down navigation)
l  Automatic related content
l  Language dependent optimizations
l  Fast
l  Adaptive to your domain data models
l  Leverages Apache Solr/Lucene

eZ Find with two main additional roles
l  eZ Find to replace your (complex) ‘fetch
content’ calls
-  Speed up template rendering, especially with
complex dynamic pages
l  eZ Find/Solr as a content and integration
engine
-  Document oriented storage system
(hello NoSQL)
-  Archive use-case
-  External content

Your tools
Credit: http://commons.wikimedia.org/wiki/File:Werkzeugwand.jpg

Core template level tools
l  Dedicated template fetch functions
l  Leveraging Solr search (including spell
check, highlighting, …)
l  More Like This
l  Raw access to Solr index (ex: integrating
foreign sources)
l  JS/AJAX
l  Term suggestions

Tuning tools for relevancy
•  Index time
•  Configuration (ezfind.ini)
•  Custom index time plugin
•  Search time
•  Boost functions
•  Elevation of objects
•  Apche Solr schema.xml and
solrconfig.xml magic

Tools for extending eZ Find
•  Custom data type plugins
•  Tailor indexing and searching for your data-types
•  General index time plugins
•  Even more tailoring and exotic dishes
•  Custom suggesters
•  Add your own vocabularies

The Solr administration interface
l  http://localhost:8983/solr/<core>/admin
l  Statistics and health monitor
l  Search index
l  Java VM (devops)
l  Advanced use
l  Learning
l  Debugging (understanding search results)
l  Tuning tool

Installation and configuration recipes

Installation and configuration recipes
l  Requirements
l  Installing the extension
l  Basic installation/activation of Solr

Solr backend-requirements
l  Java VM
-  JRE 6 or 7 (OpenJDK, Oracle/Sun)
l  Servlet container
-  Jetty shipped by default, Tomcat, ....
-  Security to be configured (by default:
open)
-  See also http://wiki.apache.org/solr/SolrInstall
l  For larger sites/indexes: enough RAM
-  Yet leave enough for the OS/file caching

Extension installation and activation
l  eZ Find extension activated the usual way
-  ActiveExtensions[]=ezfind
-  (!) Regenerate autoloads if using direct
editing of ini settings
l  Execute the DB upgrade script
-  Used for elevation
-  See extension/ezfind/sql/<db>

Putting the backend somewhere
•  Inside eZ Find extension
•  Single installation
•  Quick testing
•  Dedicated locations
•  Production setups
•  Multi-tenant setups
•  Multiple instances (development)
•  Separate the binaries and data/conf, example:
/opt/solr for binaries
/srv/solr for data/conf

Multiple ways and operating modes
for starting the Solr backend
•  Single core
•  Deprecated
•  Multiple cores
•  Multi-lingual
•  Multi-tenant
•  Multiple instances on your dev installation
•  Setup instructions: see online docs or last years
presentation

Multi-core setup advantages
•  Every language / tenant has its own
•  Index
•  Tunable analyzer options
•  Spell checker dictionary
•  Synonyms, stop word list
•  Elevate configuration
•  Additional bonuses:
•  slight increase in performance
•  core admin features

How to configure multicore setups ...
•  Create a new Solr home directory under
the java subdir
•  Put a config file solr.xml which specifies the
cores
•  Copy the conf and data directories
•  Specify the solr home when starting the
servlet container
sudo java -jar -Dsolr.solr.home=solr.multicore -jar
start.jar

Configuration of multiple cores ...
l  solr.xml as the master entry
point
l  lib for all shared jars
(extensions)
l  in each subdir, dedicated:
-  index (“data”)
-  Configuration files (“conf”)
-  (option) “lib“ with core
specific jars

Multicore master config file: solr.xml
<?xml version="1.0" encoding="UTF-8" ?>
<solr persistent="true" sharedLib="lib">
<cores adminPath="/admin/cores">
<core name="project1-eng-GB" instanceDir="pro1-eng" />
<core name="project1-ger-DE" instanceDir="pro1-ger" />
<core name="develop" instanceDir="inventory" />
</cores>
</solr>

Performance configuration options
l  Enable delayed indexation of objects (site.ini)
l  Editors will be happier (“faster publishing”)
l  Can be done globally or per class (recommended
for binary file indexing)
l  Downside: objects will only be in search results after
the configured cronjob has run

Performance configuration options (...)
l  Disable optimize on commit
-  Configure cronjob to do it once per day/week
-  Makes files compact
-  If many delete operations happen, optimize
accordingly

Performance configuration options (...)
l  Enable commitWithin (ezfind.ini)
-  Use case: large sites, where commits can also
take some time
-  Specified in milliseconds
-  No cronjobs needed
l  Only in special cases: disable direct commits
-  Indexing
-  Delete operations

Search handler configuration
l  Defaults to “ezpublish” now (Apache Solr 3.6.1), based
on “eDismax”
l  Supports Lucene syntax (wildcards)
l  Does partial language analysis in presence of wildcards
l  If upgrading from older versions: check value in
ezfind.ini
[SearchHandler]
DefaultSearchHandler=ezpublish

Devops side-dish for large scale
installations (Linux)
•  Goal: avoid crashes, slowness
•  Environment
•  Many Solr index cores
•  Many facet queries and filters used
•  Heavy traffic
•  Linux process limits (Solr startup)
•  Memory limit setting
! !ulimit -v unlimited!
•  File descriptors (open files)
ulimit -n 30000!

Basic indexing and re-indexing
l  Initial indexing: use dedicated eZ Find provided
script
-  php extension/ezfind/bin/php/updatesearchindexsolr.php -s
<admin siteaccess> --php-exec=php –conc=2
-  typical speed: 5-25 objects /sec
l  Further indexing: automatically

Basic indexing and re-indexing (…)
l  Full re-indexing with important changes
-  Schema changes in the backend Solr
-  ezfind.ini changes related to field mapping
-  Switching from single to multi-core setups
-  Upgrades of eZ Find and/or Solr

eZ Tika: indexing binary files
l  http://projects.ez.no/eztika
l  Based on Apache Tika
-  Text and meta-data extraction for a large
variety of file types
l  Extension provides
-  Standalone binary (yet another Java .jar)
-  Configuration settings
-  A stub binary file handler
-  A wrapper shell script

Basic searching, filtering and facets
recipes

Terminology 101
•  Searching
•  What you expect J
•  Includes relevancy calculations
•  Filtering
•  Narrows down the set of documents to search for
•  Does NOT influence relevancy calculations
•  Full search syntax and more for you to use
Index
FilterSearch
result

Terminology 101
•  Facets
•  Provides counts on potential filters to use
•  Tool to create navigation interfaces

Solr/Lucene search syntax 101
l  Query using “eZ Publish/eDismax” handler
l  One or more keywords
l  + or – prefix to denote required or excluded
example: +cocktail -workshop
l  Multiple terms: “minimum must match rules”
Default:
1, 2 keywords: at least one must match
3-5 keywords, at least 2-4 must match
6-7 keywords, at least 4-5 must match
above 7 keywords, 60% of them must match

Solr/Lucene search syntax 101
l  Terms and phrases
l  Term: cocktail
l  Phrase: “Elaphusa hotel”
l  Wildcards
l  Using '*': pro*
l  Using '?': ma?ch
l  Allowing certain “edit distance”: fuzzy searches
l  march~0.7
l  Proximity
l  “john doe”~10

Solr/Lucene search syntax 101(..)
l  Ranges
-  Inclusive/exclusive
-  One part may be open ended using '*'
l  Inclusive
-  [1 TO 5]
l  Exclusive
-  {0 TO 6}
l  Open ended
-  [NOW/DAY-1YEARS TO *]

Date handling
l  No real limits like unix timestamps
l  Date values in ISO 6801 format
yyyy-mm-ddThh:mm:ssZ (in UTC)
l  Macro like syntax
-  “NOW”
-  “NOW/DAY-1YEAR”
-  “NOW+3DAYS”
l  Templates: format datetime with 'solr’ operator

Searching in templates
l  You can use the standard content/search
templates and parameters
l  But much better: dedicated eZ Find fetch
functions
-  fetch( ezfind, search, hash( query, 'eZ Systems' ) )
-  fetch( ezfind, moreLikeThis, …)
-  fetch( ezfind, rawSolrRequest, …)

Dedicated search fetch parameters
•  Basic query parameters
•  query: query string
•  offset: result offset
•  limit: max number of results
•  class_id: class id’s/identifiers (string or array)
•  section_id: section identifier
•  query_handler: string (default “ezpublish”)
See doc.ez.no for the full list of parameters

Dedicated search fetch parameters
•  Advanced query parameters
•  spellcheck: array(true/false, ‘default’)
•  filter: mixed filter expression
•  facet: mixed facet expression
•  sort_by: array of hashes
•  criterium: score (default), name, class_name, published,
modified, ….
•  order: “asc” or “desc”
See doc.ez.no for the full list of parameters

Filtering
l  AND logic connects array elements using
Standard Lucene syntax.
l  Within element, ‘OR’ logick can be applied
l  Attribute identifiers are mapped to Solr
fields
l  Example
fetch( ezfind, search,
hash( query, 'cocktails',
filter, array( 'article/tags:Bol' ) ) )

eZ Find and field names
l  The normal case for filtering: 3 ways
-  array('article/title:a*') //will generate 2 filters
-  array('title:a*') //cross class attribute filtering
-  array('attr_title_s:a*') //using raw field names

eZ Find raw field names
l  Main principle: <source>_<identifier>_<type>
-  <source>: meta, attr, as
-  <identifier>: eZ Publish native identifier
-  <type>: Solr field type mapping (schema.xml)
l  Extra
-  timestamp: time when the object was indexed
-  ezf_df_text: aggregator for all text
-  ezf_sp_words: spellcheck source
l  Subattributes: another separator with 3x '_'
<source>_<identifier>___<sub_attr_id>_<type>

Filter recipes
•  A specific age: last 2 weeks
.. filter, array(  
’meta_published_dt:[NOW/DAY-2WEEKS TO NOW/DAY+1DAYS]’ ) .. 
!
Solr filter query cache friendly:
•  Lower bound: rounds on day and substracts 2 weeks
•  Upper bound: rounds on current day + 1 day in order to get also the
published items after 00:00 ‘today’

Filter recipes (…)
•  ‘or’ conditions within fields
'attr_tags_lk:(ezfind ezsummercamp netgen)’ ) .. 
!
•  ‘or’ conditions across fields
’(attr_length_si:[2 TO 5]) (attr_color_s:red)’ ) .. 
!

Facets
•  Facet types
•  field: enumeration
•  function: Solr functions
•  prefix: prefix/wildcard
•  range, date
•  Main facet parameters:
•  sort: count or alphanumerical
•  limit, offset!
•  mincount!
•  missing!

Basic facet types
l  Field facets
l  Enumerate over contents
l  Can give large results, use wisely
l  Typical: keywords, object metadata
l  Functions
l  The sky is the limit
l  Gives back 1 count result
l  Prefix
l  Shortcut for a simple function facet

Range facets
l  For numerical and date ranges
l  Emits a multiple counts, depending on
parameters provided
l  Example:
fetch( ezfind, search, hash( 'query', '$queryString,
'facet',array(
hash( 'range',
hash('field', 'published',
'start', 'NOW/YEAR-3YEARS',
'end', 'NOW/YEAR+1YEAR',
'gap', '+1YEAR' ) ) ) ) )

Range facets: parameters
l  Mandatory
-  'field' (can also be custom Solr fields)
-  'start' (numeric/date)
-  'end' (numeric/date)
l  Optional
-  'hardend'
-  'include'
-  'other’

Recipes with facets and filters
•  Analytics on publishing activities in the previous
month
hash( query, '',
filter, array(
'meta_published_dt:[NOW/MONTH-1MONTHS TO NOW/MONTH]' ),
facet, array(
hash('field','meta_contentclass_id_si' ),
hash('field','meta_owner_id_si')
) ) )
•  Results in counts on content types and authors

Recipes with facets and filters (..)
•  Analytics on publishing activities in the previous
months for a certain content type, using range
facets
hash( query, '',
filter, array(
'meta_class_identifier_ms:article' ),
facet, array(
hash('range',
hash( 'field', 'published',
'start', 'NOW/MONTH-12MONTHS',
'end', 'NOW/MONTH',
'gap', '+1MONTHS' )),
) ) )

Part 2: Advanced recipes & insights
•  Tuning search result relevancy
•  Create your own data-type plugin
•  eZ Find / Solr lower-level API
•  General index time plugins
Appendix
•  Devops: replication and loadbalancing/failover
•  A deeper dive into Solr analysis

Tuning search result relevancy
l  Index time boosting
-  “Permanent boosting”
-  Best used after some real-life measurements
(logs, user feedback, dedicated tests)
-  ezfind.ini
l  Query time boosting
-  For ezpublish/eDismax request handlers
-  Fields (also meta-data)
-  Function queries
-  Multiplicative and additive boosting

Index time boosting
l  Available for:
-  Classes
-  Attributes
-  Datatypes
l  Boost factor ranges
-  [0 … 1] suppression
-  [1 … ] boosting
l  ezfind.ini

Index time boosting: ezfind.ini
example
[IndexBoost]
#ClassBoost: set boost factors on document (object) level
#format Class[<attribute identifier>]=<boost factor as int or float>
Class[]
Class[article]=4
Class[folder]=0.1
#AttributeBoost: set boost factors on attributes at field level
#you can specify the class identifier as optional (!) element for greatest flexibility
#If more than attributeidentifier is used, the last one has precedence
Attribute[]
Attribute[product/name]=8.0
Attribute[bio]=1.5
#AttributeBoost: set boost factors on attributes at field level based on their datatype
Datatype[]
Datatype[ezkeyword]=3.0
#ReverseRelatedScale: scale factor to use in $boost = $boost + <scalefactor> * <number of reverse relations>
ReverseRelatedScale=0
ReverseRelatedScale=0.8

Query time boosting
l  Boosting types and corresponding sub-
parameters
-  'field'
-  'mfunctions'
-  'queries'
-  'functions'
l  Properly supported only since eZ Publish 5, eZ
Find master

Query time boosting: 'fields'
l  Example
.. 'boost_functions', hash('fields',array
('article/tags:3'))..
or with a raw Solr field identifier
.. 'boost_functions', hash('fields',array
('attr_tags_lk:3'))..

Query time boosting: 'mfunctions'
l  Multiplicative
l  No need to know raw relevancy numbers
l  Multiplies the individual score with the specified
function(s)
l  Preferred over other query boost functions in
most cases!

Recipe: promote more recent content
•  Parameter snippet
... 'boost_functions',
hash('mfunctions', array('recip(
ms(NOW/DAY,meta_published_dt),
1.58e-11,2.0,0.5)' )) …
•  Scaling parameters for reciprocal function
•  recip(x,m,a,b) = a/ (m*x+b)
•  x = age in milliseconds
•  m = 1.58 e-11 (milliseconds in 6 months)-1
•  a,b scaling factors (a “amplitude”, b “speed of age
decline”)

Recipe: promote more recent content (…)
Implementing
1+(a/m*x+b)
with
a = 2
b = 0.5
m = 1.58e-11
x = age in
milliseconds

Query time boosting: 'queries'
l  These are added to the main query and need to
follow the Solr/Lucene query format ans specify
the boost factor explicitely for it
l  Example
..'boost_functions', hash('queries',
array(
'meta_class_identifier_ms:article^10'))..
l  Also available in ini settings (applies always)
[QueryBoost]
#RawBoostQueries[]
RawBoostQueries[]=meta_class_identifier_ms:summary^4

Query time boosting: ’ functions'
l  These are like mfunctions, but add their value
to the relevancy score
l  Usually 'mfunctions' are the easier choice
l  Example
..'boost_functions',
hash('functions', array('sum(product
(attr_importance_si,0.1),1)')) ..

Solr has many functions to use
l  Strings
l  Numbers and mapping
l  Date math
l  Geospatial
http://wiki.apache.org/solr/FunctionQuery/

Absolute boosting: elevation
l  If a query term matches, one or more objects
are pushed to the top
l  Query term has to be part of the object
l  Dedicated admin interface J

Custom datatype handlers
l  Usually for “complex” datatypes
-  Subfields (!)
l  Can optionally be context aware
-  Facets/Sort
-  Search
-  Filter

Create your own datatype handler
l  Derive from a base class:
-  ezfSolrDocumentFieldBase
-  Naming convention
l  Provide at least two methods
-  “schema” data: (sub)field names
-  Data to index
l  Starting point
-  extension/ezfind/classes:
ezfsolrdocumentfielddummyexample.php
l  Add in ezfind.ini, [Indexoptions]

Overview of eZ Find / Solr lower level API

Base classes to know
l  extension/ezfind/classes
-  ezsolrbase.php
handles communication with Solr backends
-  ezsolrdoc.php
creates proper XML structures for indexing
-  ezfsolrutils.php
easy to use higher level functions
l  Let's have a look ...

Index Time Plugin Mechanism
l  Write your own functions to:
-  Expand the Solr fields per object
-  Modify existing fields
-  Change per object and per field boosting
dynamically
l  Use cases
-  Complex custom data, partially external
-  Boost documents based on page views, user
score, ….

Index time plugins (...)
l  Implement the following interface
l  docList is the array of eZSolrDocs to be sent
to Solr, one per language for the given
contentObject
interface ezfIndexPlugin
{
/**
* @var eZContentObject $contentObject
* @var array $docList
*/
public function modify(eZContentObject $contentObject, &$docList);
}

Index time plugins (...)
l  Activate your plugin in ezfind.ini
-  Global
-  Per content class
[IndexPlugins]
# Allow injection of custom fields and manipulation of fields/boost parameters
# at index time
# This can be defined at the class level or general
General[]
#General[]=ezfIndexParentName
#Classhooks will only be called for objects of the specified class
Class[]
Class[myspecialclass]=ezfIndexParentName

Customizing autocomplete
•  Tweaking schema.xml
•  Goal: decrease "noise"
•  Use copyfield directives to use only selected input
fields and aggregate into a custom autocomplete
source field
•  Adapt ezfind.ini settings

Customizing autocomplete:
schema.xml
<fields>
..
<field name="my_autocomplete_field" type="textgen"
indexed="true" stored="true" multiValued="true"/>
..
<copyField source="*_lk" dest="my_autocomplete_field"/>
..
</fields>
Example source: only lowercased tags

Customizing autocomplete:
ezfind.ini
[AutoCompleteSettings]
AutoComplete=enabled
# The maximum number of suggestions to return from search engine.
Limit=10
# Facet field used by autocomplete.
FacetField=my_autocomplete_field

Suggested exercises

Warm up exercise
l  Make sure you are on the latest code base
l  Play with the Lucene syntax supported by the
new ezpubish/eDismax handler:
-  Proximity searches
-  Fuzzy searches
-  Wildcards
-  Ranges
And see what happens

Exercise: boosting
l  Use the new 'mfunctions' parameter to boost
more recent values
l  Tweak your content with ratings and boost
higher rated articles

Exercise: Facets & attribute filtering
l  Adapt the previous examples/recipes
l  Try to facet and filters on classnames
-  As a field facet (enumerate all classes)
-  As a set of several query facets (enumerate
only a selection)
l  Range facets
-  Date ranges

Exercise: sub-attribute filtering on
a related object
l  Create an override template for a dummy
node
l  In the template add code for fetching with
ez find, search with an empty query string,
but use a filter with a subbatribute clause
{def $searchResults = fetch( 'ezfind', 'search',
hash( 'query', '',
'filter', array('article/testrelation/caption:specialvalue1')))

A last plug: You are invited to our
5th anniversary!
conference.phpbenelux.eu/2014/

Appendix A
Replication and loadbalancing

Replication / Distribution
l  Solr 3.x (current stable eZ Find)
-  Master/slave model (pull)
-  Easy to setup
l  Solr 4.x (future eZ Find?)
-  “SolrCloud”, dustributed capabilities (push)
-  Apache Zookeeper based
-  A bit more complicated setup
-  Automatic failover, monitoring

Master/Slave replication
l  solrconfig.xml
-  Activate handlers
-  Allow parameters (slave must know master)
-  Define replication trigger points (commit/
optimize/manual)
-  Define config files to replicate if needed
l  HTTP REST API
l  Status monitoring in admin interface

Replication: example config
<requestHandler name="/replication" class="solr.ReplicationHandler" >
<lst name="master">
<str name="enable">${enable.master:false}</str>
<str name="replicateAfter">commit</str>
<str name="replicateAfter">startup</str>
<str name="replicateAfter">optimize</str>
<str name="confFiles">elevate.xml</str>
</lst>
<lst name="slave">
<str name="enable">${enable.slave:false}</str>
<str name="masterUrl">http://${master.core.url:localhost:8983}/${solr.core.name}/replication</str>
<str name="pollInterval">${poll.time:'00:00:10'}</str>
</lst>
</requestHandler>
Startup parameters from command line or system

Replication: starting master and slave
Slave!
!
java -Denable.slave=true -Dmaster.core.url=master:8983/solr -Dsolr.solr.home=/var/solr -jar start.jar!
!
!
Master!
!
java -Denable.master=true -Dsolr.solr.home=/var/solr -jar start.jar &!

Replication and load balancing
•  Reverse proxy and rewrite rules
•  Point eZ Find Solr URI’s to load balancer URI
•  Direct reads to slaves
•  Direct everything else to master

Replication and load balancing (…)
Listen 8988!
<VirtualHost *:8988>!
# Need: mod_proxy mod_proxy_http mod_proxy_balancer active!
!
<Proxy balancer://solrread>!
# just two, localhost and the Solr master server as a hot stand-by: may also add the second
webserver!
BalancerMember http://localhost:8983!
BalancerMember http://master-solr:8983 status=+H!
</Proxy>!
!
<Proxy balancer://solrwrite>!
# just the Solr master server!
BalancerMember http://master-solr:8983!
</Proxy>!
!
RewriteEngine On!
!
# Send select to the solrread balancer!
RewriteCond %{REQUEST_URI} ^/(.*)select/$!
RewriteRule ^/(.*)$ balancer://solrread/$1 [P]!
!
# Send all others to the write balancer!
RewriteRule ^/(.*)$ balancer://solrwrite/$1 [P]!
!
ProxyPassReverse / balancer://solrwrite!
ProxyPassReverse / balancer://solrread!
</VirtualHost>!
Apache mod_proxy example

Appendix B
Inside Solr analysis

A deeper dive into
Apache Solr
l  From index → document → field
l  Schema.xml
l  What happens under the hood

The Solr/Lucene index
l  Inverted index
l  Holds a collection of “documents” (hello NoSQL)
l  Document
-  Collection of fields
-  Flexible schema!
-  Unique ID (user defined)
l  Solr uses a XML based config file:
schema.xml

Field types and fields
l  Various field types, derived from base classes
l  Indexed (optional)
-  usually analyzed & tokenized
-  makes it searchable and sortable
l  Stored (optional)
-  contains also the original submitted content
-  content can be part of the request response
l  Can be multi-valued!
-  opens possibilities beyond full text search

Field definitions: schema.xml
l  Field types
-  text
-  numerical
-  dates
-  location
-  … (about 30 in total)
l  Actual fields (name, definition, properties)
l  Dynamic fields
l  Copy fields (as aggregators)

schema.xml: simple field type examples
<fieldType name="string" class="solr.StrField"
sortMissingLast="true" omitNorms="true"/>

<fieldType name="boolean" class="solr.BoolField"
sortMissingLast="true" omitNorms="true"/>

<fieldType name="tdate" class="solr.TrieDateField"
omitNorms="true" precisionStep="6" positionIncrementGap="0"/>

<fieldType name="text_ws" class="solr.TextField"
positionIncrementGap="100">
<analyzer>
<tokenizer class="solr.WhitespaceTokenizerFactory"/>
</analyzer>
</fieldType>

schema.xml: more complex field type

<fieldType name="textgen" class="solr.TextField" positionIncrementGap="100">
<analyzer type="index">
<filter class="solr.StopFilterFactory" ignoreCase="true" words="stopwords.txt"
enablePositionIncrements="false" />
<filter class="solr.WordDelimiterFilterFactory" generateWordParts="1"
generateNumberParts="1" catenateWords="1" catenateNumbers="1" catenateAll="0"
splitOnCaseChange="0"/>
<filter class="solr.LowerCaseFilterFactory"/>
</analyzer>
<analyzer type="query">
<filter class="solr.SynonymFilterFactory" synonyms="synonyms.txt" ignoreCase="true"
expand="true"/>
<filter class="solr.StopFilterFactory"
ignoreCase="true"
words="stopwords.txt"
enablePositionIncrements="true"
/>
<filter class="solr.WordDelimiterFilterFactory" generateWordParts="1"
generateNumberParts="1" catenateWords="0" catenateNumbers="0" catenateAll="0"
splitOnCaseChange="0"/>
<filter class="solr.LowerCaseFilterFactory"/>
</analyzer>
</fieldType>

Analysis
l  Solr does not really search your text, but rather
the terms that result from the analysis of text
l  Typically a chain of
-  Character filter(s)
-  Tokenisation
-  Filter A
-  Filter B
-  …

Solr comes with many tokenizers and
filters
l  Some are language specific
l  Others are very specialised
l  It is very important to get this right
otherwise, you may not get what you expect!

Text analysis examples
Input phrase:
Ivo Lukač presents a geek-interview on the eZSummerCamp.

Character filters
l  Used to cleanup text before tokenizing
-  HTMLStripCharFilter (strips html, xml, js, css)
-  MappingCharFilter (normalisation of
characters, removing accents)
-  Regular expression filter

Tokenizers
l  Convert text to tokens (terms)
l  You can define only one per field/analyzer
l  Examples
-  WhitespaceTokenizer (splits on white space)
-  StandardTokenizer
-  CJK variants

Additional filters
l  Many possible per field/analyzer
l  Many delivered with Solr out of the box
l  If not enough, write a tiny bit of Java or look for
contributions
l  Examples ...

Phonetic filters
l  PhoneticFilterFactory
l  “sounds like” transformations and matching
l  Algorithms:
-  Metaphone
-  Double Metaphone
-  Soundex
-  Refined Soundex

Reversing Filter
l  Reverses the order of characters
l  Use: allow “leading wildcards”
l  *thing => gniht*
l  A lot faster (prefixes)

Synonyms
l  Inject synonyms for certain terms
l  Language specific
l  Best used for query time analysis
-  may inflate the search index too much
-  decreases relevancy

Stemming
l  Reduce terms to their root form
-  Plural forms
-  Conjugations
l  Language specific (or not relevant, CJK)
l  Many specialised stemmers available
-  Most european languages
-  Some exotic ones through contributions
outside ASF

Copy fields
l  Analysis is done differently for
-  searching/filtering
-  faceting/sorting
l  Stemming and not stemming in different fields
can increase relevance of results
l  Use copy fields in schema.xml or do it client
side

Geospatial fields
l  Solr dedicated fields
-  Latitude Longitude type (trunk)
l  Special geospatial functions in filtering &
boosting
-  Haversine distance (geosphere)
-  Simple ranges (squares in 2-D)
-  Special query constructs (upcoming)

Dedicated fields for every context in
eZ Find if configured
l  Context
-  Search
-  Facets
-  Filtering (usually the same as search)
-  Sorting
l  ezfind.ini
l  Also for custom handlers if needed (see part 6)

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