elasticsearch.
anticipate issues. scale faster.
-elasticsearch is a search engine built ontop of Apache's Lucene library
-elasticsearch uses Lucene internally for all of its indexing and searching, and also aims to make full text search easy by hiding Lucene's complexities behind a simple, coherent API
what is elasticsearch?
-
elasticsearch provides a distributed, multitenant-capable full-text search engine with a RESTful web interface and schema-free JSON documents
- Faceted Search
- Distributed Search
- Scalable Search
Faceted Search
- Combining Navigational & Direct search paradigms
- Navigational Search
- Enable users to browse information space by narrowing the scope of their quest in a predetermined order
- Direct Search
- Queries = bag of words in a text box
Distributed Search
- Indices can be divided into shards
-
Scalable Search
-querying denormalized data (JSON)
use of inverted indexing
-elasticsearch uses a structure called an inverted index which is designed to allow very fast full text searches
elasticsearch relevance example
-query for 'rock climbing' in the employees collection
GET /megacorp/employee/_search
{
"query" : {
"match" : {
"about" : "rock climbing"
}
}
}
query example result
{
...
"hits": {
"total": 2,
"max_score": 0.16273327,
"hits": [
{
...
"_score": 0.16273327,
"_source": {
"first_name": "John",
"last_name": "Smith",
"age": 25,
"about": "I love to go rock climbing",
"interests": [ "sports", "music" ]
}
},
{
...
"_score": 0.016878016,
"_source": {
"first_name": "Jane",
"last_name": "Smith",
"age": 32,
"about": "I like to collect rock albums",
"interests": [ "music" ]
}
}
]
}
}
