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anggadarkprince / learn-elasticsearch

Sandbox to learn elasticsearch

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Elasticsearch

Install elasticsearch

Lucene document

elastic.json

{
    "_id": "324",
    "name": "Angga Ari"
    "gender": "male",
    emails: [
        "angga.aw92@mail.com",
        "angga123@mail",
    ],
    "location": {
        city: "Surabaya",
        country: "Indonesia",
    },
    "contacts: [
        {
            type: "whatsapp primary",
            value: "2853423"
        },
        {
            type: "phone",
            value: "2853423"
        }
    ]
}

lucene.doc

{
    "_id": ["324"],
    "name": ["Angga Ari"]
    "gender": ["male"],
    "location": ["Surabaya"]
    "emails": ["angga.aw92@mail.com", "angga123@mail"],
    "location.city": ["Surabaya"],
    "location.country": ["Indonesia"],
    "contacts.type": ["whatsapp", "primary", "phone"],
    "contacts.value: ["2853423"] // only single because other value is same
}

Index

  • similar to table in relational database
  • elasticsearch doesn't have database separation
  • usually we add prefix app name to distnguist between app in same elasticsearch server
  • should be lowercase, allow use - + and _ (not in the front of name), max 255 bytes

Create index customer, product, orders

PUT http://localhost:9200/customers PUT http://localhost:9200/products PUT http://localhost:9200/orders

Get all orders

GET http://localhost:9200/_cat/indices?v

Delete index

DELETE http://localhost:9200/customers

Dynamic mapping

  • not store null value
  • true/false as boolean
  • double as float
  • long as long
  • array depends on the first element type
  • string can be parsed as date, float, long, text depends on it can be detected as known type or not
  • string date yyyy/MM/dd HH:mm:ss by default will be parsed as date (auto parsing can be disabled: date_detection to false), format date can be configured: dynamic_date_formats (multiple format can be detected)

Elasticsearch API

Create API

  • store data into index POST / PUT /<index>/_create/<id> { field: value }
  • will return conflict response when id is exist, see Index API

Get API

  • get data with metadata GET /<index>/_doc/<id>
  • get data without metadata GET /<index>/_source/<id>
  • return 404 if not exists

Check exists API

  • HEAD /<index>/_doc/<id> return 200 or 404

Multiget API

  • get from all index POST /_mget { "docs": [ { "_id": 1, "_index": "orders" }, ... ] }
  • get from specific index POST /<index>/_mget { "ids": ["1", "2", ...] }

Search API

  • POST /_search
  • POST /<index>/_search

Pagination API

  • using query param from, default 0
  • size as total each page, default 10

Sorting API

  • <field>:<direction>
  • direction can be asc or desc
  • for multi sort using coma (,) as separator: field1:asc,field2:desc

Index API for create and update

  • Create if not exist and update if exist (replace)
  • POST /<index>/_doc/<id> { field: value }

Update API for edit some field of document (not replaced)

  • POST /<index>/_update/<id> { "doc": { field: value } }

Delete API to delete document

  • DELETE /<index>/_doc/<id>

Bulk API

  • POST /_bulk
  • POST /<index>/_bulk

Alias

  • alias for index, usefull when we have multiple version of index, client mention the index rather than direct index name
  • POST /_aliases { "actions": [ {"add": {"alias": "customer", "index": "customers"}}, {"remove": {"alias": "customer", "index": "customers"}} ] }

Reindex API

  • Copy data index to new index
  • POST /_reindex { "source": {"index": "orders"}, "dest": {"index": "order_v2"} }

Source Field

  • Elasticsearch store data into lucine document but add original json in _source key
  • Size of document will be doubled (lucine doc + original json data)
  • Filter field in parameter, search or get (_doc, _source) API
  • _search?_source_includes: include fields of document
  • _doc/<id>?_source_excludes: exclude fields of document

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Sandbox to learn elasticsearch