elasticsearch权威指南(v7.9.3)

一、参考

Elasticsearch: 权威指南

二、名词解释

(1) DSL，domain-specific language，领域特定语言

三、基础入门

3.1 索引员工文档

变更:

一个索引下没有多个type， 只有一个_doc的类型

# 索引一个文档
PUT /megacorp/_doc/1
{
    "first_name" : "John",
    "last_name" :  "Smith",
    "age" :        25,
    "about" :      "I love to go rock climbing",
    "interests": [ "sports", "music" ]
}

# 返回值

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

3.2 检索文档

# 检索文档
GET megacorp/_doc/1

# 返回值
{
  "_index" : "megacorp",
  "_type" : "_doc",
  "_id" : "1",
  "_version" : 1,
  "_seq_no" : 0,
  "_primary_term" : 1,
  "found" : true,
  "_source" : {
    "first_name" : "John",
    "last_name" : "Smith",
    "age" : 25,
    "about" : "I love to go rock climbing",
    "interests" : [
      "sports",
      "music"
    ]
  }
}

3.3 短语查询

# 查询语句
GET /megacorp/_search
{
  "query": {
    "match_phrase": {
      "about": "rock climbing"
    }
  }
}

# 返回值
{
  "took" : 0,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 1,
      "relation" : "eq"
    },
    "max_score" : 1.4167401,
    "hits" : [
      {
        "_index" : "megacorp",
        "_type" : "_doc",
        "_id" : "1",
        "_score" : 1.4167401,
        "_source" : {
          "first_name" : "John",
          "last_name" : "Smith",
          "age" : 25,
          "about" : "I love to go rock climbing",
          "interests" : [
            "sports",
            "music"
          ]
        }
      }
    ]
  }
}

3.4 高亮查询

# 高亮查询
GET /megacorp/_search
{
  "query": {
    "match_phrase": {
      "about": "rock climbing"
    }
  },
  "highlight": {
    "fields": {
      "about": {}
    }
  }
}

# 返回值
{
  "took" : 79,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 1,
      "relation" : "eq"
    },
    "max_score" : 1.4167401,
    "hits" : [
      {
        "_index" : "megacorp",
        "_type" : "_doc",
        "_id" : "1",
        "_score" : 1.4167401,
        "_source" : {
          "first_name" : "John",
          "last_name" : "Smith",
          "age" : 25,
          "about" : "I love to go rock climbing",
          "interests" : [
            "sports",
            "music"
          ]
        },
        "highlight" : {
          "about" : [
            "I love to go <em>rock</em> <em>climbing</em>"
          ]
        }
      }
    ]
  }
}

3.5 分析

# 聚合查询
GET /megacorp/_search
{
  "size": 0, 
  "query": {
    "match": {
      "last_name": "smith"
    }
  },
  "aggs": {
    "all_interests": {
      "terms": {
        "field": "interests.keyword"
      },
      "aggs": {
        "avg_age": {
          "avg": {
            "field": "age"
          }
        }
      }
    }
  }
}

# 返回值
{
  "took" : 3,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 2,
      "relation" : "eq"
    },
    "max_score" : null,
    "hits" : [ ]
  },
  "aggregations" : {
    "all_interests" : {
      "doc_count_error_upper_bound" : 0,
      "sum_other_doc_count" : 0,
      "buckets" : [
        {
          "key" : "music",
          "doc_count" : 2,
          "avg_age" : {
            "value" : 28.5
          }
        },
        {
          "key" : "sports",
          "doc_count" : 1,
          "avg_age" : {
            "value" : 25.0
          }
        }
      ]
    }
  }
}

四、集群内的原理