Elasticsearch란

Apache Lucene 기반으로 개발 된 실시간 분산 검색 및 분석 엔진

RDBMS와의 차이

RDBMS	ElasticSearch
Database	Index
Table	Type
Row	Document
Column	Field
Index	Analyze
Primary key	_id
Schema	Mapping
Physical partition	Shard
Logical partition	Route
Relational	Parent/Chille, Nested
SQL	Query DSL

도커로 설치해보기

$ docker pull docker.elastic.co/elasticsearch/elasticsearch:7.6.2

$ docker run -d --name elasticsearch -p 9200:9200 -p 9300:9300 -e "discovery.type=single-node" docker.elastic.co/elasticsearch/elasticsearch:7.6.2

9200: http 포트, 9300: 전송포트

생성 - /{index}/{type}/{id}

id를 입력하지 않으면 랜덤한 문자열을 id로 생성한다.

Request

POST http://localhost:9200/database/user/1
{
  "name": "zkdlu",
  "age": 25
}

Response

{
  "_index": "database",
  "_type": "user",
  "_id": "5",
  "_version": 1,
  "result": "created",
  "_shards": {
      "total": 2,
      "successful": 1,
      "failed": 0
  },
  "_seq_no": 5,
  "_primary_term": 1
}

수정 - /{index}/{type{id}}

Request

PUT http://localhost:9200/database/user/1
{
  "name": "zkdlu",
  "age": 24
}

Response

{
   "_index": "database",
   "_type": "user",
   "_id": "1",
   "_version": 3,
   "result": "updated",
   "_shards": {
       "total": 2,
       "successful": 1,
       "failed": 0
   },
   "_seq_no": 6,
   "_primary_term": 1
}

조회 - /{index}/{type}/{id}

Request

GET http://localhost:9200/database/user/1

Response

{
    "_index": "database",
    "_type": "user",
    "_id": "1",
    "_version": 3,
    "_seq_no": 6,
    "_primary_term": 1,
    "found": true,
    "_source": {
        "name": "zkdlu",
        "age": 24
    }
}

삭제 - /{index}/{type}/{id}

Request

DELETE http://localhost:9200/database/user/1

Response

{
    "_index": "database",
    "_type": "user",
    "_id": "1",
    "_version": 4,
    "result": "deleted",
    "_shards": {
        "total": 2,
        "successful": 1,
        "failed": 0
    },
    "_seq_no": 7,
    "_primary_term": 1
}

전체 조회 - /{index}/{type}/{id}/_search

Request

GET http://localhost:9200/database/user/_search

Response

{
    "took": 945,
    "timed_out": false,
    "_shards": {
        "total": 1,
        "successful": 1,
        "skipped": 0,
        "failed": 0
    },
    "hits": {
        "total": {
            "value": 4,
            "relation": "eq"
        },
        "max_score": 1.0,
      "hits": [
           {
               "_index": "database",
               "_type": "user",
               "_id": "2",
               "_score": 1.0,
               "_source": {
                   "name": "zkdlu2",
                   "age": 25
               }
           },
           ... 생략

전체 조건 조회 - /{index}/{type}/{id}/_search?q={key}:{value}

Request

GET localhost:9200/database/user/_search?q=name:zkdlu

Response

{
    "took": 2,
    "timed_out": false,
    "_shards": {
        "total": 1,
        "successful": 1,
        "skipped": 0,
        "failed": 0
    },
    "hits": {
        "total": {
            "value": 1,
            "relation": "eq"
        },
        "max_score": 1.0296195,
        "hits": [
            {
                "_index": "database",
                "_type": "user",
                "_id": "1",
                "_score": 1.0296195,
                "_source": {
                    "name": "zkdlu",
                    "age": 25
                }
            }
        ]
    }
}

버전 업그레이드

작성 후 알았는데 위의 API는 Elasticsearch 6.x 버전에서 사용 되는 api이다.

7.x 로 올라오면서 Type 구조를 삭제하고 Document는 _doc으로 대체되었습니다.

변경 된 API 비교

• Search

  API	6.x	7.x
  search	/{index}/{type}/_search	{index}/_search
  msearch	/{index}/{type}/_msearch	/{index}/_msearch
  count	/{index}/{type}/_count	/{index}/_count
  explain	/{index}/{type}/{id}/_explain	/{index}/_explain/{id}
  search template	/{index}/{type}/_search/template	/{index}/_search/template
  msearch template	/{index}/{type}/_msearch/template	/{index}/_msearch/template

• Document

  API	6.x	7.x
  index	{index}/{type}/{id}	/{index}/_doc/{id}
  delete	/{index}/{type}/{id}	/{index}/_doc/{id}
  get	/{index}/{type}/{id}	/{index}/_doc/{id}
  update	/{index}/{type}/{id}/_update	/{index}/_update/{id}
  get source	/{index}/{type}/{id}/_source	/{index}/_source/{id}
  bulk	/{index}/{type}/_bulk	/{index}/_bulk
  mget	/{index}/{type}/_mget	/{index}/_mget
  termvectors	/{index}/{type}/{id}/_termvector	/{index}/_termvector/{id}
  mtermvectors	/{index}/{type}/_mtermvectors	/{index}/_mtermvectors

• Index

  API	6.x	7.x
  create index	/{index}	ㅡ
  get mapping	/{index}/_mapping/{type}	/{index}/_mapping
  put mapping	/{index}/_mapping/{type}	/{index}/_mapping
  get field mapping	/{index}/{type}/_mapping/field/{fields}	/{index}/_mapping/field/{fields}
  get template	/_template/{template}	ㅡ
  put template	/_template/{template}	ㅡ