See conference video - http://www.lucidimagination.com/devzone/events/conferences/ApacheLuceneEurocon2011 Solr features a little known internal document processing pipeline called the UpdateRequestProcesssorChain or simply the UpdateChain. In this talk we'll discuss the importance of document processing, when the UpdateChain works well and what limitations it's got. We'll then go on to propose a range of possible improvements. Topics include: Examples of use with demo How to write your own UpdateProcessor, best practices Example: Tika as an UpdateProcessor A vision for future improvements

1. Improving the Solr Update Chain
Jan Høydahl

2. What will I cover?
Who is Jan Høydahl?
Intro to Solr’s (hidden) UpdateChain
How to write your own UpdateProcessors
Example: Web crawl @ Oslo University
A vision for future improvements
Conclusion
2

5. Jan Høydahl
1995: Developer telecom
1998: Java developer
2000: Search - FAST
2006: Lucene
2007: Cominvent
2011: Lucene committer
> 100 projects
5

6. Cominvent AS
Consulting & support www.solrtraining.com
Lucene/Solr
FAST
6

7. Why document processing?
Analysis is Field oriented
Filters only see the “local” field
7

8. Why document processing?
But what if you want to:
Add or remove fields?
Make decisions based on other fields?
We need a way to modify the Document
8

9. Why document processing?
Doc1
name
postcode
programmer
cv_pdf_url
near Barcelona
9

10. Why document processing?
Doc1
name
postcode
programmer
latlong
near Barcelona
cv_pdf_url
cv_text
10

11. Why document processing?
Client
Doc1
name
postcode
latlong
cv_pdf_url
cv_text
11

12. Why document processing?
Client
Doc1
name
postcode 3rd party
latlong pipeline
cv_pdf_url
cv_text
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13. Solr’s Update Chain
13

14. The Update Chain
14

15. The Update Chain
Doc
name
postcode
cv_pdf_url
15

16. The Update Chain
Postcode
ToLatLong
Processor
Doc Doc
name name
postcode postcode
cv_pdf_url latlong
cv_pdf_url
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17. The Update Chain
Postcode
UrlFetcher
ToLatLong
Processor
Processor
Doc Doc Doc
name name name
postcode postcode postcode
cv_pdf_url latlong latlong
cv_pdf_url cv_pdf_url
cv_pdf_bin
15

18. The Update Chain
Postcode Tika
UrlFetcher
ToLatLong Extracting
Processor
Processor Processor
Doc Doc Doc Doc
name name name name
postcode postcode postcode postcode
cv_pdf_url latlong latlong latlong
cv_pdf_url cv_pdf_url cv_pdf_url
cv_pdf_bin cv_pdf_bin
cv_text
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21. How it’s wired
Chain definition in solrconfig.xml:
Choose chain in your update request:
.../solr/update/xml?..&update.chain=cv-chain
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22. Other examples
Language Identification
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23. Other examples
Company
The Apache Software Foundation
(ASF) is a non-profit corporation to
support Apache software projects.
The ASF was formed from the
Apache Group and incorporated in
Delaware, U.S., in June 1999.
Location Date
Entity extraction
19

25. Writing your own processor
21

26. Writing your own processor
21

27. Writing your own processor
22

28. Writing your own processor
23

29. Writing your own processor
•Make generic processors - parameterized
•Use SchemaAware, SolrCoreAware and
ResourceLoaderAware interfaces
•Prefix param names to avoid name clash
•Testing and testable methods
•Donate back to Apache & document on Wiki
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30. Web crawl with
Language Detection
@ Oslo University
25

31. Solr @ Oslo University
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32. Solr @ Oslo University
<?xml version="1.0"?>
<updateRequestProcessorChain name="web">
<processor class="solr.update.processor.LanguageIdentifierUpdateProcessorFactory">
<lst name="defaults">
<str name="langid.fl">title,content</str>
<str name="langid.idField">url</str>
<str name="langid.fallbackFields"></str>
<str name="langid.fallback">no</str>
<str name="langid.whitelist">no,en</str>
<str name="langid.langField">language</str>
<str name="langid.langsField">languages</str>
<bool name="langid.overwrite">true</bool>
<bool name="langid.map">true</bool>
<str name="langid.map.fl">title,content</str>
<double name="langid.threshold">0.5</double>
</lst>
</processor>
<processor class="no.uio.update.processor.RegexpReplaceProcessorFactory">
<bool name="enabled">true</bool>
<str name="fl">content_no content_en</str>
<str name="pattern">[su00A0]+</str>
<str name="replacement"> </str>
</processor>
<processor class="no.uio.update.processor.FixDuplicateContentTitleProcessorFactory">
<bool name="enabled">true</bool>
<str name="title.fl">title_no,title_en</str>
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<str name="content.fl">content_no,content_en</str>

33. Solr @ Oslo University
<?xml version="1.0"?>
<updateRequestProcessorChain name="web">
<processor class="solr.update.processor.LanguageIdentifierUpd
<lst name="defaults">
<str name="langid.fl">title,content</str>
<str name="langid.idField">url</str>
<str name="langid.fallbackFields"></str>
<str name="langid.fallback">no</str>
<str name="langid.whitelist">no,en</str>
<str name="langid.langField">language</str>
<str name="langid.langsField">languages</str>
<bool name="langid.overwrite">true</bool>
<bool name="langid.map">true</bool>
<str name="langid.map.fl">title,content</str>
<double name="langid.threshold">0.5</double>
</lst>
</processor>
<processor class="no.uio.update.processor.RegexpReplaceProces
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34. Solr @ Oslo University
<?xml version="1.0"?>
<updateRequestProcessorChain name="web">
<processor class="solr.update.processor.LanguageIdentifierUpdateProcessorFactory">
<lst name="defaults">
<str name="langid.fl">title,content</str>
<str name="langid.idField">url</str>
<str name="langid.fallbackFields"></str>
<str name="langid.fallback">no</str>
<str name="langid.whitelist">no,en</str>
<str name="langid.langField">language</str>
<str name="langid.langsField">languages</str>
<bool name="langid.overwrite">true</bool>
<bool name="langid.map">true</bool>
<str name="langid.map.fl">title,content</str>
<double name="langid.threshold">0.5</double>
</lst>
</processor>
<processor class="no.uio.update.processor.RegexpReplaceProcessorFactory">
<bool name="enabled">true</bool>
<str name="fl">content_no content_en</str>
<str name="pattern">[su00A0]+</str>
<str name="replacement"> </str>
</processor>
<processor class="no.uio.update.processor.FixDuplicateContentTitleProcessorFactory">
<bool name="enabled">true</bool>
<str name="title.fl">title_no,title_en</str>
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<str name="content.fl">content_no,content_en</str>

35. </processor>
<processor class="no.uio.update.processor.RegexpReplaceProcessorFactory">
<bool name="enabled">true</bool>
Solr @ Oslo University
<str name="fl">content_no content_en</str>
<str name="pattern">[su00A0]+</str>
<str name="replacement"> </str>
</processor>
<processor class="no.uio.update.processor.FixDuplicateContentTitleProcessorFactory">
<bool name="enabled">true</bool>
<str name="title.fl">title_no,title_en</str>
<str name="content.fl">content_no,content_en</str>
<str name="contentType.field">tika_Content-Type</str>
<str name="contentType.regexp">^(text/html|application/xhtml).*</str>
</processor>
<processor class="no.uio.update.processor.URLClassifyProcessorFactory">
<bool name="enabled">true</bool>
<str name="domainOutputField">host</str>
<str name="canonicalUrlOutputField">canonicalurl</str>
</processor>
<processor class="no.uio.update.processor.RegexpBoostProcessorFactory">
<bool name="enabled">true</bool>
<str name="inputField">url</str>
<str name="boostField">urlboost</str>
<str name="boostFilename">${solr.solr.home}/conf/rank/urlboosts.txt</str>
</processor>
<processor class="no.uio.update.processor.StaticRankProcessorFactory">
<bool name="enabled">true</bool>
<str name="inputField">canonicalurl</str>
<str name="anchorField">anchortext</str>
<str name="rankField">docrank</str>
<str name="rankFilename">${solr.solr.home}/conf/rank/rankinfo.txt</str>
</processor>
<processor class="solr.LogUpdateProcessorFactory"/>
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36. </processor>
<processor class="no.uio.update.processor.RegexpReplaceProcessorFactory">
<bool name="enabled">true</bool>
Solr @ Oslo University
<str name="fl">content_no content_en</str>
<str name="pattern">[su00A0]+</str>
<str name="replacement"> </str>
</processor>
<processor class="no.uio.update.processor.FixDuplicateContentTitleProcessorFactory">
<bool name="enabled">true</bool>
<str name="title.fl">title_no,title_en</str>
<str name="content.fl">content_no,content_en</str>
<str name="contentType.field">tika_Content-Type</str>
<str name="contentType.regexp">^(text/html|application/xhtml).*</str>
</processor>
<processor class="no.uio.update.processor.URLClassifyProcessorFactory">
<bool name="enabled">true</bool>
<str name="domainOutputField">host</str>
<str name="canonicalUrlOutputField">canonicalurl</str>
</processor>
<processor class="no.uio.update.processor.RegexpBoostProcessorFactory">
<bool name="enabled">true</bool>
<str name="inputField">url</str>
<str name="boostField">urlboost</str>
<str name="boostFilename">${solr.solr.home}/conf/rank/urlboosts.txt</str>
</processor>
<processor class="no.uio.update.processor.StaticRankProcessorFactory">
<bool name="enabled">true</bool>
<str name="inputField">canonicalurl</str>
<str name="anchorField">anchortext</str>
<str name="rankField">docrank</str>
<str name="rankFilename">${solr.solr.home}/conf/rank/rankinfo.txt</str>
</processor>
<processor class="solr.LogUpdateProcessorFactory"/>
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37. </processor>
<processor class="no.uio.update.processor.RegexpReplaceProcessorFactory">
<bool name="enabled">true</bool>
Solr @ Oslo University
<str name="fl">content_no content_en</str>
<str name="pattern">[su00A0]+</str>
<str name="replacement"> </str>
</processor>
<processor class="no.uio.update.processor.FixDuplicateContentTitleProcessorFactory">
<bool name="enabled">true</bool>
<str name="title.fl">title_no,title_en</str>
<str name="content.fl">content_no,content_en</str>
<str name="contentType.field">tika_Content-Type</str>
<str name="contentType.regexp">^(text/html|application/xhtml).*</str>
</processor>
<processor class="no.uio.update.processor.URLClassifyProcessorFactory">
<bool name="enabled">true</bool>
<str name="domainOutputField">host</str>
<str name="canonicalUrlOutputField">canonicalurl</str>
</processor>
<processor class="no.uio.update.processor.RegexpBoostProcessorFactory">
<bool name="enabled">true</bool>
<str name="inputField">url</str>
<str name="boostField">urlboost</str>
<str name="boostFilename">${solr.solr.home}/conf/rank/urlboosts.txt</str>
</processor>
<processor class="no.uio.update.processor.StaticRankProcessorFactory">
<bool name="enabled">true</bool>
<str name="inputField">canonicalurl</str>
<str name="anchorField">anchortext</str>
<str name="rankField">docrank</str>
<str name="rankFilename">${solr.solr.home}/conf/rank/rankinfo.txt</str>
</processor>
<processor class="solr.LogUpdateProcessorFactory"/>
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38. </processor>
<processor class="no.uio.update.processor.RegexpReplaceProcessorFactory">
<bool name="enabled">true</bool>
Solr @ Oslo University
<str name="fl">content_no content_en</str>
<str name="pattern">[su00A0]+</str>
<str name="replacement"> </str>
</processor>
<processor class="no.uio.update.processor.FixDuplicateContentTitleProcessorFactory">
<bool name="enabled">true</bool>
<str name="title.fl">title_no,title_en</str>
<str name="content.fl">content_no,content_en</str>
<str name="contentType.field">tika_Content-Type</str>
<str name="contentType.regexp">^(text/html|application/xhtml).*</str>
</processor>
<processor class="no.uio.update.processor.URLClassifyProcessorFactory">
<bool name="enabled">true</bool>
<str name="domainOutputField">host</str>
<str name="canonicalUrlOutputField">canonicalurl</str>
</processor>
<processor class="no.uio.update.processor.RegexpBoostProcessorFactory">
<bool name="enabled">true</bool>
<str name="inputField">url</str>
<str name="boostField">urlboost</str>
<str name="boostFilename">${solr.solr.home}/conf/rank/urlboosts.txt</str>
</processor>
<processor class="no.uio.update.processor.StaticRankProcessorFactory">
<bool name="enabled">true</bool>
<str name="inputField">canonicalurl</str>
<str name="anchorField">anchortext</str>
<str name="rankField">docrank</str>
<str name="rankFilename">${solr.solr.home}/conf/rank/rankinfo.txt</str>
</processor>
<processor class="solr.LogUpdateProcessorFactory"/>
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39. Donations back to Apache
SOLR-2599: FieldCopyProcessor
SOLR-2825: RegexReplaceProcessor
SOLR-2826: URLClassifyProcessor
SOLR-2827: RegexpBoostProcessor
SOLR-2828: StaticRankProcessor
Binary Document Dumper (?)
Many thanks for the donations!
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42. Room for
improvement?
32

43. Improvements
Processors re-created for every request
Duplication of config between chains
No support for non-linear or sub chains
Does not scale very well
Lack native scripting language support
34

44. Improvements
Pain:
Potentially expensive initialization
StaticRankProcessor: read&parse 50.000 lines
Proposed cure:
Keep persistent state object in factory:
private final Map<Object,Object> sharedObjCache
new StaticRankProcessor(params, request,
response, nextProcessor, sharedObjCache);
Processor uses sharedObjCache for state
35

45. Improvements
Processors re-created for every request
Duplication of config between chains
No support for non-linear or sub chains
Does not scale very well
Lack native scripting language support
36

46. Improvements
Pain:
Multi chains often need identical Processors
UiO’s two chains share 80% -> copy/paste
Proposed cure:
Allow sharing of named instances
Define:
<processor name="langid" class="..">
Refer:
<processor ref="langid" />
See SOLR-2823
37

47. Improvements
Processors re-created for every request
Duplication of config between chains
No support for non-linear or sub chains
Does not scale very well
Lack native scripting language support
38

48. Improvements
Pain:
Chains are linear only
Hard to do branching, sub chains, conditional...
Proposed cure (SOLR-2841):
New scriptable Update Chain - alternative to XML
Script chain logic in solr/conf/updateproc.groovy
Full flexibility:
chain myChain {
if(doc.getFieldValue("type").equals("pdf"))
process(tikaproc)
}
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49. Improvements
Processors re-created for every request
Duplication of config between chains
No support for non-linear chains or sub chains
Does not scale very well
Lack native scripting language support
40

50. Improvements
Pain:
Single threaded
Heavy processing not efficient
Proposed cure:
Local: Use multi threaded update requests
SolrCloud: Dedicated nodes, role=“processor” ?
Wrap an external pipeline in UpdateProcessor
Example: OpenPipelineUpdateProcessor ?
41

51. Improvements
Processors re-created for every request
Duplication of config between chains
No support for non-linear chains or sub chains
Does not scale very well
Lack native scripting language support
42

52. Improvements
Pain:
Not really a “problem” :-)
Nice to write processors in Python, Groovy, JS...
Proposed cure:
Now: Finish SOLR-1725: Script based Processor
Later: Make scripts first-class processors
<processor script="myScript.py" />
or
<processor ref="myScript" />
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53. One last thing...
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54. New standalone framework?
•The UpdateChain is Solr specific
•Interest for a pure pipeline framework
•Search engine independent
•Scalable
•Rich pool of processors
•Several existing candidates
•Some initial thoughts:
http://wiki.apache.org/solr/DocumentProcessing
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55. Summary
46

56. Summary
•Document centric vs field centric processing
•UpdateChain is there - use it!
•Works well for most “light” cases
•Scaling issues, but caching config may help
•More processors welcome!
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57. Questions?
Jan Høydahl, Cominvent AS
@cominvent
www.cominvent.com

58. Extra
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59. Alternative pipelines
OpenPipeline (Dieselpoint)
•OpenPipe (T-Rank, now on GitHub)
•Pypes (ESR)
•UIMA (Apache)
•Eclipse SMILA
•Apache commons pipeline
•Piped (FoundIT, Norway)
•Behemoth (DigitaPebble)
•FindWise and TwigKit also has some technology
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60. Calling out from UpdateChain
This is one way an
external pipeline
system can be
integrated with Solr.
The main benefit of
such a method is you
can continue to feed
content with SolrJ, DIH
or other Update
Request Handlers.
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61. Scaling with external pipeline
Here is a more
advanced,
distributed
case, where a
Solr node is
dedicated for
processing, and
the entry point
Solr only
dispatches the
requests.
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