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Agenda

Why Elasticsearch?

Fuzzy Searches

Relevant Searches

Pagination

Aggregations

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Derivatives

Suggestions

Elasticsearch vs RelationalDB

Node 1

index = books

index = blogs

RDBMS

database = books

database = blogs

type = travel

type = cooking

type = travel

type = cooking

table= travel

table= cooking

table = travel

table = cooking

Scaling & Sharding

Node 1

primary shard 1

primary shard 2

primary shard 3

primary shard 4

primary shard 5

Scaling & Sharding contd..

Node 1

Node 2

Node 3

primaryshard 1

primary shard 2

replica shard 3

primaryshard 3

primaryshard 4

replica shard 5

replica shard 2

primary shard 5

replica shard 4

replica shard 1

How to use Elasticsearch?

Application

Database Elasticsearch

http://www.elasticsearch.org/download

Installation

CRUD Operations

Create

curl –XPUT localhost:9200/books/travel/1 –d ‘ { ”title": "Journey's of a Life Time - 500 Best Trips", "author": "National Geographic", "releaseDate": "2013-10-25T19:00" }

Get

Mapping

Update

Concurrency Control

Document , version 1

Document , version 2

Document , version 2

FAIL

SUCCESS

Delete

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Search

Search

Query Search & Pagination

Search

Analyzers

Character Filtering

Tokenizer

Lowercase

Stopwords

Synonyms

“I Love to Travel & Work.”

Analyzed Data

“I Love to Travel and Work”

“I”, “Love”, “to”, “Travel”, “and”, “Work”

“i”, “love”, “to”, “travel”, “and”, “work”

“i”, “love”, “travel”, “work”

“i”, “like”, “travel”, “work”

Inverted Index

Terms Documents Frequencies

i id1 id1 -> 1

like id1, id3 id1 -> 1, id3 -> 5

travel id1, id2 id1 -> 3, id2 -> 2

work id2, id3, id5 id2 -> 3, id3 -> 1, id5 -> 2

Inverted Index An inverted index is a data structure that maps a word to a document.

Full Text Search "author": { "type": "string” “index”: “analyzed”, “analyzer”: “french” }

Exact String Search "author": { "type": "string” “index”: “not_analyzed” }

Not Searchable "author": { "type": "string” “index”: “no” } }

Analyzers available in Elasticsearch

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Types of Queries

Request with Query & Filters

Filters vs Queries exact match full text search

binary yes/no relevance scoring

fast relatively slow

cacheable not cacheable

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Aggregations

Handling Typos with N-Grams

Uni-gram = e, l, a, s, t, i, c

Bi-gram = el, la, as, st, ti, ic

Tri-gram = ela, las, ast, sti, tic

Handling Typos with N-Grams

Autocomplete with Edge Grams

Search Results

travel

training

transfer

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Battle Tested Lessons

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Battle Tested Lessons contd..

Let’s Connect