Elasticsearch 基础入门

廖子博 / 2024-09-28 / 原文

安装

安装 Java

安装 ES

tar zxvf elasticsearch-<version>

启动 ES

./bin/elasticsearch

查看 ES 状态

-k 允许不安全的 https 连接
-u 用户名密码，在第一次启动ES时打印，可以通过 bin/elasticsearch-reset-password -u elastic 重置密码

curl -k -u elastic:passwd https://localhost:9200

curl -X <VERB> '<PROTOCOL>://<HOST>:<PORT>?<QUERY_STRING>' -d <BODY>

查看文档数量

curl -k -u elastic:passwd https://localhost:9200/_count

端口：

集群间使用 9300 端口通信
RESTful API 使用 9200 端口通信

基础入门

索引员工数据

curl -XPUT -H 'Content-Type: application/json' -k -u elastic:passwd https://localhost:9200/employee/_doc/1 -d \
'{
    "first_name" : "John",
    "last_name" :  "Smith",
    "age" :        25,
    "about" :      "I love to go rock climbing",
    "interests": [ "sports", "music" ]
}'

curl -XPUT -H 'Content-Type: application/json' -k -u elastic:passwd https://localhost:9200/employee/_doc/2 -d \
'{
    "first_name" :  "Jane",
    "last_name" :   "Smith",
    "age" :         32,
    "about" :       "I like to collect rock albums",
    "interests":  [ "music" ]
}'

curl -XPUT -H 'Content-Type: application/json' -k -u elastic:passwd https://localhost:9200/employee/_doc/3 -d \
'{
    "first_name" :  "Douglas",
    "last_name" :   "Fir",
    "age" :         35,
    "about":        "I like to build cabinets",
    "interests":  [ "forestry" ]
}'

检索员工数据

curl -k -u elastic:passwd https://localhost:9200/employee/_doc/1?pretty"

PUT 创建/更新文档
GET 检索文档
DELETE 删除文档
HEAD 检查文档是否存在 curl -I -k -u elastic:passwd https://localhost:9200/employee/_doc/1

简单搜索

检索所有数据，默认返回 10 条

 curl -k -u elastic:passwd "https://localhost:9200/employee/_search?pretty"

搜索 last_name 为 Smith 的文档（查询字符串 query-string）

curl -k -u elastic:passwd "https://localhost:9200/employee/_search?pretty&q=last_name:Smith"

查询表达式

curl -H 'Content-Type: application/json' -k -u elastic:passwd "https://localhost:9200/employee/_search?pretty" -d \
'{
    "query": {
        "match": {
            "last_name": "Smith"
        }
    }
}'

过滤器

过滤器支持高效地执行结构化查询

range 过滤器

curl -H 'Content-Type: application/json' -k -u elastic:passwd "https://localhost:9200/employee/_search?pretty" -d \
'{
    "query": {
        "bool": {
            "must": [{
                "match": {
                    "last_name": "Smith"
                }
            }],
            "filter": [{
                "range": {
                    "age": {"gt": 30}
                }
            }]
        }
    }
}'

全文搜索

返回结果会根据相关性排序

curl -H 'Content-Type: application/json' -k -u elastic:passwd "https://localhost:9200/employee/_search?pretty" -d \
'{
    "query": {
        "match": {
            "about": "rock climbing"
        }
    }
}'

短语搜索

检索包含短语 "rock climbing"

curl -H 'Content-Type: application/json' -k -u elastic:passwd "https://localhost:9200/employee/_search?pretty" -d \
'{
    "query": {
        "match_phrase": {
            "about": "rock climbing"
        }
    }
}'

高亮搜索

curl -H 'Content-Type: application/json' -k -u elastic:passwd "https://localhost:9200/employee/_search?pretty" -d \
'{
    "query": {
        "match_phrase": {
            "about": "rock climbing"
        }
    },
    "highlight": {
        "fields": {
            "about": {}
        }
    }
}'

聚合

根据 interests 分组统计，all_interests 是别名

https://stackoverflow.com/questions/59298209/how-to-fix-elasticsearch-fielddata-is-disabled-on-text-fields-by-default-for-k

curl -H 'Content-Type: application/json' -k -u elastic:passwd "https://localhost:9200/employee/_search?pretty" -d \
'{
    "aggs": {
        "all_interests": {
            "terms": {
                "field": "interests.keyword"
            }
        }
    }
}'

先进行搜索，在对结果根据 interests 分组统计

curl -H 'Content-Type: application/json' -k -u elastic:passwd "https://localhost:9200/employee/_search?pretty" -d \
'{
    "query": {
        "match": {
            "last_name": "Smith"
        }
    },
    "aggs": {
        "all_interests": {
            "terms": {
                "field": "interests.keyword"
            }
        }
    }
}'

根据 interests 分组，再计算每组的平均年龄

curl -H 'Content-Type: application/json' -k -u elastic:passwd "https://localhost:9200/employee/_search?pretty" -d \
'{
    "aggs": {
        "all_interests": {
            "terms": {
                "field": "interests.keyword"
            },
            "aggs": {
                "avg_age": {
                    "avg": {"field": "age"}
                }
            }
        }

    }
}'