软糖

Elastic Search Step by Step 2

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Searching with elasticsearch

This section will focus on query

query lite

URI Search

  • /movies/movie/_search?q=title:star
  • /movies/movie/_search?q=+year:>2010+title:trek
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curl -H 'Content-Type: application/json' -X GET http://{{host}}:9200/movies/movie/_search?q=title:star&pretty
# becareful about url encoding
curl -H 'Content-Type: application/json' -X GET http://{{host}}:9200/movies/movie/_search?q=%2Byear%3A%3E2010%2Btitle%3Atrek

request body search

query DSL is in the request body as JSON

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curl -H 'Content-Type: application/json' -X GET http://{{host}}:9200/movies/movie/_search?pretty -d `
{
    "query": {
        "match": {
            "title": "star"
        }
    }
}
`
  • filters ask a yes/no question of your data
  • queries return data in terms of relevance

use filters when you can - they are faster and cacheable.

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curl -H 'Content-Type: application/json' -X GET http://{{host}}:9200/movies/movie/_search?pretty -d '
{
    "query": {
        "bool": {
            "must": { "term": {"title": "trek" }},
            "filter": {"range": {"year": {"gte": 2010}}}
        }
    }
}'

some types of filters

filters are wrapped in a filter: {} block

could combine filters inside queries, or queries inside filters

  • term: filter by exact values
    • {“term”: {“year”: 2014”}}
  • terms: match if any exact values in a list match
    • {“terms”: {“genre”: [“Sci-Fi”, “Adventure”]}}
  • range: Find numbers or dates in a given range(gt, gte, lt, lte)
    • {“range”: {“year”: {“gte”: 2010}}}
  • exists: Find doc where a field exists
    • {“exists”: {“field”: “tags”}}
  • missing: Find doc where a field is missing
    • {“missing”: {field”: “tags”}}
  • bool: Combine filters with Boolean logic (must, must_not, should)

some types of queries

queries are wrapped in a query: {} block

could combine filters inside queries, or queries inside filters

  • match_all: return all documents and is the default. Normally used with a filter.
    • {“match_all”: {}}
  • match: searches analyzed results, such as full text search.
    • {“match”: {“title”: “star”}}
  • multi-match: run the same query on multiple fields.
    • {“multi_match”: {“query”: “star”, “fields”: [“title”, “synopsis”]}}
  • bool: Works like a bool filter, but results are scored by relevance.
  • match_phase: must find all terms, in the right order
    • {“match_phase”: {“title”: “star wars”}}
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curl -H 'Content-Type: application/json' -X GET http://{{host}}:9200/movies/movie/_search?pretty -d '
{
    "query": {
        "match_phase": {"title": "star wars"}
    }
}'

slop

order matters, but you’re OK with some words being in between the terms.

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curl -H 'Content-Type: application/json' -X GET http://{{host}}:9200/movies/movie/_search?pretty -d '
{
    "query": {
        "match_phase": {"title": "star beyond", "slop": 1}
    }
}'

“quick brown fox” would match “quick fox” with a slop of 1

proximity queries

Remember this: query results are sorted by relevance.

Just use a really high slop for proximity queries

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curl -H 'Content-Type: application/json' -X GET http://{{host}}:9200/movies/movie/_search?pretty -d '
{
    "query": {
        "match_phase": {"title": "star beyond", "slop": 100}
    }
}'