Beyond full-text searches with Lucene and Solr


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Case study using Solr to index the content of existing websites. Presented at ApacheCon EU 2007, Amsterdam.

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Beyond full-text searches with Lucene and Solr

  1. 1. Beyond full-text searches With Lucene and Solr Bertrand Delacrétaz ApacheCon EU 2007, Amsterdam slides revision: 2007-05-03
  2. 2. Slides at How to graft a Lucene-based dynamic navigation system on an search-challenged CMS using Solr. As seen from the “Solr integrator” point of view. Beyond full-text?
  3. 3. - a Solr client
  4. 4. - a Solr client
  5. 5. The Project Deliver a rich video player experience Users explore much more than they search Existing content stored in two separate CMSes with very different content models (and http/XML interfaces)
  6. 6. Client system overview Ajax + HTML Apache Solr HTTP server Search server HTTP/JSON Lucene index replicated index for backup
  7. 7. the Solr search server
  8. 8. What is Solr? Solr HTTP/XML servlet Lucene index See also
  9. 9. Solr architecture Diagram by Yonik Seeley
  10. 10. Indexing in Solr <add> <doc> <field name=quot;idquot;>9885A004</field> <field name=quot;namequot;>Canon PowerShot SD500</field> <field name=quot;categoryquot;>camera</field> HTTP <field name=quot;featuresquot;>3x optical zoom</field> POST <field name=quot;featuresquot;>aluminum case</field> <field name=quot;weightquot;>6.4</field> <field name=quot;pricequot;>329.95</field> </doc> </add> “Solr XML” documents are POSTed to Solr via HTTP Field names and types are defined in the Solr schema
  11. 11. Solr indexing schema <field name=quot;idquot; type=quot;stringquot; indexed=quot;truequot; stored=quot;truequot;/> <field name=quot;categoryquot; type=quot;text_wsquot; indexed=quot;truequot; stored=quot;truequot;/> <dynamicField name=quot;*_twsquot; type=quot;text_wsquot; indexed=quot;truequot; stored=quot;truequot;/> <dynamicField name=quot;*_dtquot; type=quot;datequot; indexed=quot;truequot; stored=quot;truequot;/> <fieldtype name=quot;sfloatquot; class=quot;Solr.SortableFloatFieldquot;sortMissingLast=quot;truequot;/> <uniqueKey>id</uniqueKey> <copyField source=quot;catquot; dest=quot;textquot;/> <copyField source=quot;namequot; dest=quot;textquot;/> <copyField source=quot;namequot; dest=quot;nameSortquot;/> <copyField source=quot;manuquot; dest=quot;textquot;/>
  12. 12. Field content analysis <fieldtype name=quot;text_frquot; class=quot;Solr.TextFieldquot;> Le Châtelain <analyzer> et ses chevaux <tokenizer class=quot;Solr.StandardTokenizerFactoryquot;/> <filter class=quot;Solr.ISOLatin1AccentFilterFactoryquot;/> <filter class=quot;Solr.LowerCaseFilterFactoryquot;/> <filter class=quot;Solr.StopFilterFactoryquot; words=quot;french-stopwords.txtquot; ignoreCase=quot;truequot;/> <filter chatelain class=quot;Solr.SnowballPorterFilterFactoryquot; cheval language=quot;Frenchquot;/> </analyzer> </fieldtype>
  13. 13. Solr Field Analysis test page
  14. 14. Solr queries & fl=solr_id,title <result numFound=quot;2quot; start=quot;0quot;> <doc> <str name=quot;solr_idquot;></str> <str name=quot;titlequot;>ApacheCon Amsterdam</str> </doc> <doc> <str name=quot;solr_idquot;></str> <str name=quot;titlequot;>Geeks are upon us</str> </doc> </result> Enhanced Lucene query language as standard
  15. 15. Play it again, JSON!,title&wt=json {quot;responsequot;: {quot;numFoundquot;:54,quot;startquot;:0, quot;docsquot;:[ {quot;solr_idquot;:quot;;, quot;titlequot;:quot;ApacheCon Amsterdamquot; }, {quot;solr_idquot;:quot;;, quot;titlequot;:quot;Geeks are upon usquot; }, ...
  16. 16. Solr live statistics
  17. 17. Solr Function Query A Function query influences the score by a function of a field's numeric value or ordinal. // OrdFieldSource ord(myfield) // ReverseOrdFieldSource rord(myfield) // LinearFloatFunction on numeric field value linear(myfield,1,2) // MaxFloatFunction of LinearFloatFunction on numeric field value or constant max(linear(myfield,1,2),100) // ReciprocalFloatFunction on numeric field value recip(myfield,1,2,3) _val_:quot;linear(recip(rord(broadcast_date),1,1000,1000),11,0)quot;
  18. 18. That’s our client Ajax + HTML Apache Solr HTTP server Search server Solr schema and analyzers HTTP/JSON Lucene index
  19. 19. Indexing
  20. 20. Indexing Process cron scheduler Legacy curl, HTTP/XML Solr XML CMS XSLT Issues: Change/delete signals? Polling? RSS feeds? Legacy content structure and consistency Indexing delay Deleted/retired documents Non-transactional behavior
  21. 21. Content Normalization cms A XML HTTP Content Solr HTTP Normalization XML cms B Convert to “Solr XML”. XML Common field names. Normalized values. -> unified acces
  22. 22. Normalized and unified values <field name=””>story.cmsA.12129</field> <field name=”role”>story</field> <field name=”topic”>news</field> <field name=”topic”>sports</field> <field name=”author”>Bob S. Ponge</field> <field name=””>person.438</field> <field name=”link.related”>story.cmsB.73-1</field>
  23. 23. More than “just” full-text searches <field name=””>person.438</field> <field name=”link.related”>story.cmsB.73-1</field>
  24. 24. Content Mining? content normalization Unified navigation and queries
  25. 25. Testing “How do I break this thing before it breaks by itself?” “testing” picture: taliesin on
  26. 26. Use-cases based testing Do I find “cheval” when searching for “chevaux”? Is document 98.345 found when searching for “+montreux -casino AND role:story”? etc... Reference data required for such tests: Solr indexes are collection of files that can easily be saved Why not automate these? read on...
  27. 27. Automated functional testing # Scenarii are executed by our auto-test tool, based # on htmlunit ( # test a query that returns no results request : /solr/select?wt=xmlt&q=thismustnotbefound match : /response/result/@numFound : 0 dontMatch : /response/result/@numFound : 1 # test a title query request : /solr/select?q=title%3Afootball match : contains(/response//doc[1]/str[@name='title'],'ootball') : true Test are run as JUnit tests, against a Solr instance.
  28. 28. Stress tests Generate heaps of semi-random query URLs, and replay them in many HTTP clients simultaneously using httpstone http://solr...&q=quot;attirerquot; role:audio quot;enfantsquot; quot;fidéliserquot; http://solr...&q=quot;fidéliserquot; quot;carottesquot; role:story quot;enfants...quot; http://solr...&q=quot;surtoutquot; quot;adultesquot; quot;histoirequot; quot;L'avisquot; http://solr...&q=quot;Résultatsquot; quot;enfants...quot; quot;publicitéquot; role:video http://solr...&q=quot;lunettesquot; quot;différences?quot; quot;Résultatsquot; quot;fabrications,quot; http://solr...&q=quot;attirerquot; role:story quot;solaires:quot; quot;rend-t-onquot; http://solr...&q=role:audio quot;quellesquot; quot;Mêmesquot; quot;Mêmesquot; ...
  29. 29. Test outcomes Explain search features with use cases Avoid regressions with automated tests Tune the index and analyzers with automated functional tests Get a feel for scalability with stress tests Build confidence before launches!
  30. 30. Lessons Learned
  31. 31. Lessons Learned (a.k.a “conclusion”) Solr opens the doors to Lucene! Designing the “right” indexing content model takes time. Do not hesitate to duplicate fields with different indexing parameters, denormalized, aggregated, etc. Content unification enables “content mining”. Tune and run automated tests. Repeat. Repeat. Repeat...
  32. 32. References “Modern Information Retrieval”, Ricardo Baeza-Yates Other ApacheCon EU 2007 presentations: