ES 之索引别名的使用
在开发中，随着业务需求的迭代，较老的业务逻辑就要面临更新甚至是重构，而对于 ES 来说，为了适应新的业务逻辑，可能就要对原有的索引做一些修改，比如对某些字段做调整，甚至是重建索引。而做这些操作的时候，可能会对业务造成影响，甚至是停机调整等问题。由此，ES 提供了索引别名来解决这些问题。 索引别名就像一个快捷方式或是软连接，可以指向一个或多个索引，也可以给任意一个需要索引名的 API 来使用。别名的应用为程序提供了极大地灵活性。
查询别名
GET：localhost:9200/nba/_alias GET：localhost:9200/_alias
新增别名
方式一：POST：localhost:9200/_aliases { "actions": [ { "add": { "index": "nba", "alias": "nba_v1.0" } } ] } 方式二：PUT：localhost:9200/nba/_alias/nba_v1.1
删除别名
方式一：POST：localhost:9200/_aliases { "actions": [ { "remove": { "index": "nba", "alias": "nba_v1.0" } } ] } 方式二：DELETE：localhost:9200/nba/_alias/nba_v1.1
重命名
POST：localhost:9200/_aliases { "actions": [ { "remove": { "index": "nba", "alias": "nba_v1.0" } }, { "add": { "index": "nba", "alias": "nba_v2.0" } } ] }
为多个索引指定一个别名
POST：localhost:9200/_aliases { "actions": [ { "add": { "index": "nba", "alias": "national_player" } }, { "add": { "index": "wnba", "alias": "national_player" } } ] }
为同个索引指定多个别名
POST：localhost:9200/_aliases { "actions": [ { "add": { "index": "nba", "alias": "nba_v2.1" } }, { "add": { "index": "nba", "alias": "nba_v2.2" } } ] }
通过别名读索引
当别名指定了一个索引，则查出一个索引 GET：localhost:9200/nba_v2.1 当别名指定了多个索引，则查出多个索引 GET：localhost:9200/national_player
通过别名写索引
当别名指定了一个索引，则可以做写的操作
POST：localhost:9200/nba_v2.1/_doc/566 { "countryEn": "Croatia", "teamName": "快船", "birthDay": 858661200000, "country": "克罗地亚", "teamCityEn": "LA", "code": "ivica_zubac", "displayAffiliation": "Croatia", "displayName": "伊维察 祖巴茨哥哥", "schoolType": "", "teamConference": "西部", "teamConferenceEn": "Western", "weight": "108.9 公斤", "teamCity": "洛杉矶", "playYear": 3, "jerseyNo": "40", "teamNameEn": "Clippers", "draft": 2016, "displayNameEn": "Ivica Zubac", "heightValue": 2.16, "birthDayStr": "1997-03-18", "position": "中锋", "age": 22, "playerId": "1627826" }
当别名指定了多个索引，可以指定写某个索引
POST：localhost:9200/_aliases { "actions": [ { "add": { "index": "nba", "alias": "national_player", "is_write_index": true } }, { "add": { "index": "wnba", "alias": "national_player" } } ] } POST /national_player/_doc/566 { "countryEn": "Croatia", "teamName": "快船", "birthDay": 858661200000, "country": "克罗地亚", "teamCityEn": "LA", "code": "ivica_zubac", "displayAffiliation": "Croatia", "displayName": "伊维察 祖巴茨妹妹", "schoolType": "", "teamConference": "西部", "teamConferenceEn": "Western", "weight": "108.9 公斤", "teamCity": "洛洛杉矶", "playYear": 3, "jerseyNo": "40", "teamNameEn": "Clippers", "draft": 2016, "displayNameEn": "Ivica Zubac", "heightValue": 2.16, "birthDayStr": "1997-03-18", "position": "中锋", "age": 22, "playerId": "1627826" }
ES 之如何重建索引
Elastic Search 是一个实时的分布式搜索引擎，为用户提供搜索服务，当我们决定存储某种数据时，在创建索引的时候需要将数据结构完整确定下来，与此同时索引的设定和很多固定配置将不能改变。当需要改变数据结构时，就需要重新建立索引，为此，Elastic 团队提供了很多辅助工具帮助开发人员进行重建索引。
步骤
- nba 取一个别名 nba_latest, nba_latest 作为对外使用
- 新增一个索引 nba_20220101，结构复制于 nba 索引，根据业务要求修改字段
- 将 nba 数据同步到 nba_20220101
- 给 nba_20220101 添加别名 nba_latest，删除 nba 别名 nba_latest
- 删除 nba 索引
我们对外提供访问 nba 索引时使用的是 nba_latest 别名
新增一个索引(比如修改字段类型，jerseyNo 改成 keyword 类型)
PUT：localhost:9200/nba_20220101 { "mappings": { "properties": { "age": { "type": "integer" }, "birthDay": { "type": "date" }, "birthDayStr": { "type": "keyword" }, "code": { "type": "text" }, "country": { "type": "keyword" }, "countryEn": { "type": "keyword" }, "displayAffiliation": { "type": "text" }, "displayName": { "type": "text" }, "displayNameEn": { "type": "text" }, "draft": { "type": "long" }, "heightValue": { "type": "float" }, "jerseyNo": { "type": "keyword" }, "playYear": { "type": "long" }, "playerId": { "type": "keyword" }, "position": { "type": "text" }, "schoolType": { "type": "text" }, "teamCity": { "type": "text" }, "teamCityEn": { "type": "text" }, "teamConference": { "type": "keyword" }, "teamConferenceEn": { "type": "keyword" }, "teamName": { "type": "keyword" }, "teamNameEn": { "type": "keyword" }, "weight": { "type": "text" } } } }
将旧索引数据 copy 到新索引
同步等待，接口将会在 reindex 结束后返回
POST：localhost:9200/_reindex { "source": { "index": "nba" }, "dest": { "index": "nba_20220101" } }
异步执行，如果 reindex 时间过长，建议加上 wait_for_completion=false 的参数条件，这样 reindex 将直接返回 taskId
POST：localhost:9200/_reindex?wait_for_completion=false { "source": { "index": "nba" }, "dest": { "index": "nba_20220101" } }
替换别名
POST：localhost:9200/_aliases { "actions": [ { "add": { "index": "nba_20220101", "alias": "nba_latest" } }, { "remove": { "index": "nba", "alias": "nba_latest" } } ] }
删除旧索引
DELETE：localhost:9200/nba
通过别名访问新索引
POST：localhost:9200/nba_latest/_search { "query": { "match": { "displayNameEn": "james" } } }
ES 之 refresh 操作
新的数据一添加到索引中立马就能搜索到，但是真实情况不是这样的。
我们使用链式命令请求，先添加一个文档，再立刻搜索，会发现搜索不到
curl -X PUT localhost:9200/star/_doc/888 -H 'Content-Type:application/json' -d '{ "displayName": "蔡徐坤" }' curl -X GET localhost:9200/star/_doc/_search?pretty
方法一：使用强制刷新
curl -X PUT localhost:9200/star/_doc/666?refresh -H 'Content-Type:application/json' -d '{ "displayName": "杨超越" }' curl -X GET localhost:9200/star/_doc/_search?pretty
方法二：修改默认更更新时间（默认时间是1s）
PUT：localhost:9200/star/_settings { "index": { "refresh_interval": "5s" } }
将 refresh 关闭
PUT：localhost:9200/star/_settings { "index": { "refresh_interval": "-1" } }
ES 之高亮查询
如果返回的结果集中很多符合条件的结果，那怎么能一眼就能看到我们想要的那个结果呢？
高亮查询
POST：localhost:9200/nba_latest/_search { "query": { "match": { "displayNameEn": "james" } }, "highlight": { "fields": { "displayNameEn": {} } } }
自定义高亮查询
POST：localhost:9200/nba_latest/_search { "query": { "match": { "displayNameEn": "james" } }, "highlight": { "fields": { "displayNameEn": { "pre_tags": [ "<h1>" ], "post_tags": [ "</h1>" ] } } } }
ES 之查询建议
查询建议，是为了给用户提供更好的搜索体验。包括：词条检查，自动补全。
Suggester
- Term suggester
- Phrase suggester
- Completion suggester
字段
Term suggester
term 词条建议器，对给输入的文本进行分词，为每个分词提供词项建议
POST：localhost:9200/nba_latest/_search { "suggest": { "my-suggestion": { "text": "jamse hardne", "term": { "suggest_mode": "missing", "field": "displayNameEn" } } } }
Phrase suggester
phrase 短语建议，在 term 的基础上，会考量多个 term 之间的关系，比如是否同时出现在索引的原文里，相邻程度，以及词频等
POST：localhost:9200/nba_latest/_search { "suggest": { "my-suggestion": { "text": "jamse harden", "phrase": { "field": "displayNameEn" } } } }
Completion suggester
Completion 完成建议
POST：localhost:9200/nba_latest/_search { "suggest": { "my-suggestion": { "text": "Miam", "completion": { "field": "teamCityEn" } } } }