Elasticsearch - Digging deeper into full text search Alexander Reelsen Community Advocate alex@elastic.co | @spinscale

TOC How to run the Elastic Stack Datatypes: range_ , date_nanos , search-as-you-type , flattened Search: Field collapsing/ top_hits , distance_feature query, vector search, phonetic search Processors: dissect , enrich , inference Index lifecycle management

Elastic Stack

Elasticsearch in 10 seconds Search Engine (FTS, Analytics, Geo), near real-time Distributed, scalable, highly available, resilient Interface: HTTP & JSON Heart of the Elastic Stack (Kibana, Logstash, Beats)

Installation & Start # https://www.elastic.co/downloads/elasticsearch wget https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-7.6.0-darwin-x86_64.tar.gz # wget https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-7.6.0-linux-x86_64.tar.gz # wget https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-7.6.0-windows-x86_64.zip tar zxf elasticsearch-7.6.0-darwin-x86_64.tar.gz cd elasticsearch-7.6.0 ./bin/elasticsearch-plugin install analysis-phonetic ./bin/elasticsearch wget https://artifacts.elastic.co/downloads/kibana/kibana-7.6.0-darwin-x86_64.tar.gz # wget https://artifacts.elastic.co/downloads/kibana/kibana-7.6.0-linux-x86_64.tar.gz # wget https://artifacts.elastic.co/downloads/kibana/kibana-7.6.0-windows-x86_64.zip tar zxf kibana-7.6.0-darwin-x86_64.tar.gz cd kibana-7.6.0 ./bin/kibana Point your browser to http://localhost:5601/

Click Dev-Tools Samples in Kibana Samples in Github

Datatypes

range_ datatype Search in ranges Supported types: integer , float , long , double , date , ip Example: Model hotel room availabilities

date_range datatype # date_range datatype PUT range_index { “mappings”: { “properties”: { “time_frame”: { “type”: “date_range” } } } } PUT range_index/_doc/hotel_1_room_404 { “time_frame” : [ { “gte” : “2015-10-31”, “lte” : “2015-11-02” }, { “gte” : “2015-11-04”, “lte” : “2015-11-05” } ] }

Search GET range_index/_search { “query”: { “range”: { “time_frame”: { “gte”: “2015-11-04”, “lte”: “2015-11-05”, “relation”: “contains” } } } }

date_nanos datatype # date_nanos datatype PUT nanos_index { “mappings”: { “properties”: { “time_in_nanos”: { “type”: “date_nanos”, “format” : “yyyy-MM-dd’T’HH:mm:ss.nX” } } } } PUT nanos_index/_bulk?refresh { “index” : {}} {“time_in_nanos”:”2019-12-31T23:59:59.999999999Z”} { “index” : {}} {“time_in_nanos”:”2019-12-31T23:59:59.999Z”}

date_nanos datatype GET nanos_index/_search { “query”: { “range”: { “time_in_nanos”: { “gt”: “2019-12-31T23:59:59.999Z” } } } }

search-as-you-type datatype One of the most requested features Very fast, but requires maintenance: completion suggester Since Elasticsearch 7.0: Lucene Block max WAND

search-as-you-type datatype # search_as_you_type datatype PUT search_index { “mappings”: { “properties”: { “title”: { “type”: “search_as_you_type” } } } }

search-as-you-type datatype PUT search_index/_bulk?refresh { “index” : {} } { “title” : “This is it!” } { “index” : {} } { “title” : “This or that?” } { “index” : {} } { “title” : “Thin or thick?” } { “index” : {} } { “title” : “This is eval!” } { “index” : {} } { “title” : “Thick is not sick” }

search-as-you-type datatype GET search_index/_search { “query”: { “match_phrase_prefix”: { “title”: “thi” } } } GET search_index/_search { “query”: { “match_phrase_prefix”: { “title”: “this i” } } } GET search_index/_search { “query”: { “match_phrase_prefix”: { “title”: “this is e” } } }

search-as-you-type datatype # no need for terms to be next to each other GET search_index/_search { “query”: { “multi_match”: { “query”: “thick s”, “type”: “bool_prefix”, “operator”: “and”, “fields”: [ “title”, “title._2gram”, “title._3gram” ] } } }

flattened datatype Maps an entire object as a single field Prevents mapping explosion Allows only for some basic queries Searching: Think of a specialized keyword datatype

flattened datatype # flattened datatype PUT bug_reports { “mappings”: { “properties”: { “labels”: { “type”: “flattened” } } } }

flattened datatype POST bug_reports/_doc/1?refresh { “title”: “Results are not sorted correctly.”, “labels”: { “priority”: “urgent”, “release”: [“v1.2.5”, “v1.3.0”], “timestamp”: { “created”: 1541458026, “closed”: 1541457010 } } }

flattened datatype POST bug_reports/_search { “query”: { “term”: {“labels”: “urgent”} } } POST bug_reports/_search { “query”: { “term”: {“labels.release”: “v1.3.0”} } }

Searching

Bulk indexing # index some book data to play around with PUT books/_bulk { “index” : { “_id” : “database-internals” } } {“isbn13”:”978-1492040347”,”author”:”Alexander Petrov”, “title”:”Database Internals: A deep-dive into how distributed data systems work”,”publisher”:”O’Reilly”,”category”:[“databases”,”information systems”],”pages”:350,”price”:47.28,”format”:”paperback”,”rating”:4.5} { “index” : { “_id” : “designing-data-intensive-applications” } } {“isbn13”:”978-1449373320”, “author”:”Martin Kleppmann”, “title”:”Designing Data-Intensive Applications: The Big Ideas Behind Reliable, Scalable, and Maintainable Systems”,”publisher”:”O’Reilly”,”category”:[“databases” ],”pages”:590,”price”:31.06,”format”:”paperback”,”rating”:4.4} { “index” : { “_id” : “kafka-the-definitive-guide” } } {“isbn13”:”978-1491936160”,”author”:[ “Neha Narkhede”, “Gwen Shapira”, “Todd Palino”], “title”:”Kafka: The Definitive Guide: Real-time data and stream processing at scale”, “publisher”:”O’Reilly”,”category”:[“databases” ],”pages”:297,”price”:37.31,”format”:”paperback”,”rating”:3.9} { “index” : { “_id” : “effective-java” } } {“isbn13”:”978-1491936160”,”author”: “Joshua Block”, “title”:”Effective Java”, “publisher”:”Addison-Wesley”, “category”:[“programming languages”, “java” ],”pages”:412,”price”:27.91,”format”:”paperback”,”rating”:4.2} { “index” : { “_id” : “daemon” } } {“isbn13”:”978-1847249616”,”author”:”Daniel Suarez”, “title”:”Daemon”,”publisher”:”Quercus”,”category”:[“dystopia”,”novel”],”pages”:448,”price”:12.03,”format”:”paperback”,”rating”:4.0} { “index” : { “_id” : “cryptonomicon” } } {“isbn13”:”978-1847249616”,”author”:”Neal Stephenson”, “title”:”Cryptonomicon”,”publisher”:”Avon”,”category”:[“thriller”, “novel” ],”pages”:1152,”price”:6.99,”format”:”paperback”,”rating”:4.0} { “index” : { “_id” : “garbage-collection-handbook” } } {“isbn13”:”978-1420082791”,”author”: [ “Richard Jones”, “Antony Hosking”, “Eliot Moss” ], “title”:”The Garbage Collection Handbook: The Art of Automatic Memory Management”,”publisher”:”Taylor & Francis”,”category”:[“programming algorithms” ],”pages”:511,”price”:87.85,”format”:”paperback”,”rating”:5.0} { “index” : { “_id” : “radical-candor” } } {“isbn13”:”978-1250258403”,”author”: “Kim Scott”, “title”:”Radical Candor: Be a Kick-Ass Boss Without Losing Your Humanity”,”publisher”:”Macmillan”,”category”:[“human resources”,”management”, “new work”],”pages”:404,”price”:7.29,”format”:”paperback”,”rating”:4.0} { “index” : { “_id” : “never-split-the-difference” } } {“isbn13”:”978-1847941497”,”author”: “Chris Voss”, “title”:”Never Split the Difference: Negotiating as if Your Life Depended on It”,”publisher”:”Random House Business”,”category”:[“negotiation”, “sales”],”pages”:288,”price”:10.49,”format”:”paperback”,”rating”:4.3} { “index” : { “_id” : “not-giving-a-fsck” } } {“isbn13”:”978-0062641540”,”author”: “Mark Manson”, “title”:”The Subtle Art of Not Giving a F*ck: A Counterintuitive Approach to Living a Good Life”,”publisher”:”Harper”,”category”:[“success”, “motivation”],”pages”:224,”price”:12.99,”format”:”paperback”,”rating”:4.4} { “index” : { “_id” : “permanent-record” } } {“isbn13”:”978-1250756541”,”author”: “Edward Snowden”, “title”:”Permanent Record”,”publisher”:”Macmillan”,”category”:[“politics”, “biography”],”pages”:339,”price”:12.99,”format”:”paperback”,”rating”:4.7}

Field Collapsing # field collapsing GET books/_search { “query”: { “bool”: { “must_not”: [ { “term”: { “category.keyword”: “novel” } } ] } }, “collapse”: { “field”: “publisher.keyword” }, “sort”: [ { “rating”: { “order”: “desc” } } ] }

top_hits Aggregation # top_hits aggregation GET books/_search { “size”: 0, “aggs”: { “by_format”: { “terms”: { “field”: “format.keyword” }, “aggs”: { “by_rating”: { “top_hits”: { “size”: 1, “sort”: [ { “rating”: “desc” } ] } } } } } }

distance_feature datatype & query # Add a new release_year field PUT books/_mapping { “properties” : { “release_year” : { “type” : “date”, “format” : “strict_year” } } }

distance_feature datatype & query # update release_year of all books PUT books/_bulk { “update” : { “_id” : “database-internals” } } { “doc” : { “release_year” : “2019” } } { “update” : { “_id” : “designing-data-intensive-applications” } } { “doc” : { “release_year” : “2017” } } { “update” : { “_id” : “kafka-the-definitive-guide” } } { “doc” : { “release_year” : “2017” } } { “update” : { “_id” : “effective-java” } } { “doc” : { “release_year” : “2017” } } { “update” : { “_id” : “daemon” } } { “doc” : { “release_year” : “2011” } } { “update” : { “_id” : “cryptonomicon” } } { “doc” : { “release_year” : “2002” } } { “update” : { “_id” : “garbage-collection-handbook” } } { “doc” : { “release_year” : “2011” } } { “update” : { “_id” : “radical-candor” } } { “doc” : { “release_year” : “2018” } } { “update” : { “_id” : “never-split-the-difference” } } { “doc” : { “release_year” : “2017” } } { “update” : { “_id” : “not-giving-a-fsck” } } { “doc” : { “release_year” : “2016” } } { “update” : { “_id” : “permanent-record” } } { “doc” : { “release_year” : “2019” } }

distance_feature datatype & query # newer books are more relevant # like function score, but waaaay faster GET /books/_search { “query”: { “bool”: { “filter”: { “range”: { “pages”: { “gte”: 500 } } }, “should”: { “distance_feature”: { “field”: “release_year”, “pivot”: “2555d”, “origin”: “now” } } } } }

Vector based scoring Scoring based on features Two datatypes: sparse & dense vectors can be used for scoring using vector field functions query vector required

Feature modelling Prefers long books: Range 0-10 Prefers good rated one: Range 0-5 Prefers cheaper books: 0-10 (inverse, 0 more than 100 EUR, 10 less than 10 EUR)

Mapping update # add vector field PUT books/_mapping { “properties”: { “vector_recommendation”: { “type”: “dense_vector”, “dims”: 3 } } }

Add vectors to documents # Add a vector for each document PUT books/_bulk { “update” : { “_id” : “database-internals” } } { “doc” : { “vector_recommendation” : [3.5, 4.5, 5.2] } } { “update” : { “_id” : “designing-data-intensive-applications” } } { “doc” : { “vector_recommendation” : [5.9, 4.4, 6.8] } } { “update” : { “_id” : “kafka-the-definitive-guide” } } { “doc” : { “vector_recommendation” : [2.97, 3.9, 6.2] } } { “update” : { “_id” : “effective-java” } } { “doc” : { “vector_recommendation” : [4.12, 4.2, 7.2] } } { “update” : { “_id” : “daemon” } } { “doc” : { “vector_recommendation” : [4.48, 4.0, 8.7] } } { “update” : { “_id” : “cryptonomicon” } } { “doc” : { “vector_recommendation” : [10.0, 4.0, 9.3] } } { “update” : { “_id” : “garbage-collection-handbook” } } { “doc” : { “vector_recommendation” : [5.1, 5.0, 1.3] } } { “update” : { “_id” : “radical-candor” } } { “doc” : { “vector_recommendation” : [4.0, 4.0, 9.2] } } { “update” : { “_id” : “never-split-the-difference” } } { “doc” : { “vector_recommendation” : [4.0, 4.3, 8.9] } } { “update” : { “_id” : “not-giving-a-fsck” } } { “doc” : { “vector_recommendation” : [2.8, 4.4, 8.9] } } { “update” : { “_id” : “permanent-record” } } { “doc” : { “vector_recommendation” : [3.3, 4.7, 8.7] } }

Search for short, cheap books with a good rating # short, good rating, cheap GET books/_search { “query”: { “script_score”: { “query” : { “match_all” : {} }, “script”: { “source”: “cosineSimilarity(params.query_vector, doc[‘vector_recommendation’]) + 1.0”, “params”: { “query_vector”: [1.0, 5.0, 10.0] } } } } }

Search for long, any priced books with a good rating # long, good rating, any price GET books/_search { “query”: { “script_score”: { “query” : { “match_all” : {} }, “script”: { “source”: “cosineSimilarity(params.query_vector, doc[‘vector_recommendation’]) + 1.0”, “params”: { “query_vector”: [10.0, 5.0, 5.0] } } } } }

Phonetic search Find similar terms by converting terms to their phonetic representation

phonetic mapping PUT phonetic_sample { “mappings”: { “properties”: { “name”: { “type”: “text”, “fields”: { “metaphone”: { “type”: “text”, “analyzer”: “metaphone_analyzer” }, “koelner”: { “type”: “text”, “analyzer”: “koelner_analyzer” }, “soundex”: { “type”: “text”, “analyzer”: “soundex_analyzer” } } } } }, “settings”: { “index”: { “analysis”: { “analyzer”: { “metaphone_analyzer”: { “tokenizer”: “standard”, “filter”: [ “lowercase”, “phonetic_filter” ] }, “soundex_analyzer”: { “tokenizer”: “standard”, “filter”: [ “lowercase”, “soundex_filter” ] }, “koelner_analyzer”: { “tokenizer”: “standard”, “filter”: [ “lowercase”, “koelner_filter” ] } }, “filter”: { “phonetic_filter”: { “type”: “phonetic”, “encoder”: “metaphone”, “replace”: false }, “soundex_filter”: { “type”: “phonetic”, “encoder”: “soundex”, “replace”: false }, “koelner_filter”: { “type”: “phonetic”, “encoder”: “koelnerphonetik”, “replace”: false } } } } } }

Metaphone/Soundex POST phonetic_sample/_analyze { “field”: “name.metaphone”, “text”: “Joe Blocks” } POST phonetic_sample/_analyze { “field”: “name.soundex”, “text”: “Joe Blocks” }

Koelner phonetik POST phonetic_sample/_analyze { “field”: “name.koelner”, “text”: “Aleksander” } POST phonetic_sample/_analyze { “field”: “name.koelner”, “text”: “Alexander” }

Meier/Maier/Mayer/Meyer PUT phonetic_sample/_bulk?refresh { “index” : { “_id” : 1 }} {“name”:”Peter Meyer”} { “index” : { “_id” : 2 }} {“name”:”Peter Meier”} { “index” : { “_id” : 3 }} {“name”:”Peter Maier”} { “index” : { “_id” : 4 }} {“name”:”Peter Mayer”} GET phonetic_sample/_search { “query”: { “match”: { “name.metaphone”: “Maier” } } } GET phonetic_sample/_search { “query”: { “match”: { “name.koelner”: “Maier” } } }

Ingest Processors

Dissect processor Grok processor is hard to configure for simple cases regular expressions are complex and CPU heavy dissect does not use regexes, syntax is simpler

Dissect processor # dissect processor POST _ingest/pipeline/_simulate { “pipeline”: { “processors”: [ { “dissect”: { “field”: “input”, “pattern”: “%{url}?%{param_string}” } }, { “kv”: { “field”: “param_string”, “target_field”: “params”, “field_split”: “&”, “value_split”: “=” } } ] }, “docs”: [ {“_source” : { “input” : “https://example.org?foo=bar&spam=eggs” } } ] }

Enrich processor Enrich documents with data from another index Processor uses an enrich policy Since: 7.5

Enrich processor: zip to city lookup # enrich processor PUT cities/_bulk?refresh { “index” : { “_id” : “munich”} } {“zip”:”80331”,”city”:”Munich”} { “index” : { “_id” : “berlin”} } {“zip”:”10965”,”city”:”Berlin”} PUT /_enrich/policy/zip-policy { “match”: { “indices”: “cities”, “match_field”: “zip”, “enrich_fields”: [ “city” ] } } POST /_enrich/policy/zip-policy/_execute GET _cat/indices/.enrich-*

Enrich processor: zip to city lookup POST /_ingest/pipeline/_simulate { “pipeline”: { “processors”: [ { “enrich”: { “policy_name”: “zip-policy”, “field”: “zip”, “target_field”: “city”, “max_matches”: “1” } } ] }, “docs”: [ { “_id”: “first”, “_source” : { “zip” : “80331” } } , { “_id”: “second”, “_source” : { “zip” : “50667” } } ] }

Inference processor Uses a pre-trained data frame analytics model to infer Built-in language identification

Inference processor # inference processor POST _ingest/pipeline/_simulate { “pipeline”: { “processors”: [ { “inference”: { “model_id”: “lang_ident_model_1”, “inference_config”: { “classification”: {}}, “field_mappings”: {} } } ] }, “docs”: [ { “_source”: { “text”: “This is an english text” } }, { “_source”: { “text”: “Das ist ein deutscher Text” } }, { “_source”: { “text”: ” ” } }, { “_source”: { “text”: “Ceci est un texte en français” } } ] } 我爱北京天安⻔

Index Lifecycle Management

Index Lifecycle Management control aging indices configuration via a lifecycle policy policy split into phases per action hot action: set priority, unfollow, rollover warm action: set priority, unfollow, read-only, allocate, shrink, force merge cold action: set priority, allocate, freeze delete action: delete

Sample policy # index lifecycle management PUT _ilm/policy/full_policy { “policy”: { “phases”: { “hot”: { “actions”: { “rollover”: { “max_age”: “7d”, “max_size”: “50G” } } }, “warm”: { “min_age”: “30d”, “actions”: { “forcemerge”: { “max_num_segments”: 1 }, “shrink”: { “number_of_shards”: 1 }, “allocate”: { “number_of_replicas”: 2 } } }, “cold”: { “min_age”: “60d”, “actions”: { “allocate”: { “require”: { “type”: “cold” } } } }, “delete”: { “min_age”: “90d”, “actions”: { “delete”: {} } } } } }

Summary

Summary Understanding search is hard Use the reference documentation Ask your users about expectations, do not guess!

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Thanks for listening Q&A Alexander Reelsen Community Advocate alex@elastic.co | @spinscale