====== Elasticsearch ======

The following assumes that elasticsearch is running on the localhost on port 9200.

How do I learn more?  https://www.elastic.co/guide/en/elasticsearch/reference/current/_executing_searches.html

===== General Info about elasticsearch instance =====

==== How is elasticsearch doing? ====

  curl -XGET 'localhost:9200/_cat/health?v&pretty' 
  curl -XGET 'localhost:9200/_cat/nodes?v’

==== What are the indices on this instance? ====

  curl -XGET 'localhost:9200/_cat/indices?v&pretty’

===== Searching Data =====


==== Viewing Data ====

This will give you, by default, the first 20 results as prettified JSON

  curl –XGET ‘localhost:9200/index/_search?pretty’

==== Filtering Results ====

Only get results that match certain criteria: 

  curl -XGET 'localhost:9200/index/_search?pretty' -H 'Content-Type: application/json' –d’{"query": { "match": { "field": "value" } } }'


  curl -XGET 'localhost:9200/index/_search?pretty' -H 'Content-Type: application/json' –d’{ "query": {
    "bool": {
      "must": [
        { "match": { "address": "mill" } },
        { "match": { "address": "lane" } }
        ]
      }
    }
  }'

==== Sorting Examples ====

Search ''index'', matching all, and sorting by ''field''

  curl -XGET 'localhost:9200/index/_search?q=*&sort=field:asc&pretty’

Search ''index'', matching all, and sorting by ''field''

  curl -XGET 'localhost:9200/index/_search?pretty' -H 'Content-Type: application/json' -d’
  {
    "query": { "match_all": {} },
    "sort": [
      { "field": "asc" }
    ]
  }'
  
==== Limiting Results ====

Only give one result back from searching ''index'': 

  curl -XGET 'localhost:9200/index/_search?q=*&size=1&pretty'
  
Give back one result, starting at search result 10, from ''index''

  curl -XGET 'localhost:9200/bank/_search?q=*&size=1&from=10&pretty'

==== Aggregations ====

Finding distinct entities

  curl -XGET 'localhost:9200/bank/_search?pretty' -H 'Content-Type: application/json' -d'
  {
    "size": 0,
    "aggs": {
      "group_by_state": {
        "terms": {
          "field": "state.keyword"
        }
      }
    }
  }'

===== Adding Information =====

==== Adding an index ====

  curl -XPUT 'localhost:9200/newindex?pretty’

==== Inserting documents to an index ====

Insert the JSON document (after the -d) into the index with the id ''newid'':

  curl –XPUT ‘localhost:9200/index/external/newid?pretty’ –d’{“field”:”data”}’


==== Adding from a File ====

  mongoimport --db dbname --collection whichcollection --file mydata.json

  curl -XPOST 'http://localhost:9200/dbname' -d @mydata.json

  curl -XPOST 'http://localhost:9200/dbname/_bulk' —data-binary @mydata.json
===== Deleting Information =====

  curl -XDELETE 'localhost:9200/students?pretty'