ES 之索引別名的使用
在開發中，隨着業務需求的迭代，較老的業務邏輯就要面臨更新甚至是重構，而對於 ES 來說，為了適應新的業務邏輯，可能就要對原有的索引做一些修改，比如對某些字段做調整，甚至是重建索引。而做這些操作的時候，可能會對業務造成影響，甚至是停機調整等問題。由此，ES 提供了索引別名來解決這些問題。 索引別名就像一個快捷方式或是軟連接，可以指向一個或多個索引，也可以給任意一個需要索引名的 API 來使用。別名的應用為程序提供了極大地靈活性。
查詢別名
GET：localhost:9200/nba/_alias GET：localhost:9200/_alias
新增別名
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
刪除別名
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" } } ] }
為多個索引指定一個別名
POST：localhost:9200/_aliases { "actions": [ { "add": { "index": "nba", "alias": "national_player" } }, { "add": { "index": "wnba", "alias": "national_player" } } ] }
為同個索引指定多個別名
POST：localhost:9200/_aliases { "actions": [ { "add": { "index": "nba", "alias": "nba_v2.1" } }, { "add": { "index": "nba", "alias": "nba_v2.2" } } ] }
通過別名讀索引
當別名指定了一個索引，則查出一個索引 GET：localhost:9200/nba_v2.1 當別名指定了多個索引，則查出多個索引 GET：localhost:9200/national_player
通過別名寫索引
當別名指定了一個索引，則可以做寫的操作
POST：localhost:9200/nba_v2.1/_doc/566 { "countryEn": "Croatia", "teamName": "快船", "birthDay": 858661200000, "country": "克羅地亞", "teamCityEn": "LA", "code": "ivica_zubac", "displayAffiliation": "Croatia", "displayName": "伊維察 祖巴茨哥哥", "schoolType": "", "teamConference": "西部", "teamConferenceEn": "Western", "weight": "108.9 公斤", "teamCity": "洛杉磯", "playYear": 3, "jerseyNo": "40", "teamNameEn": "Clippers", "draft": 2016, "displayNameEn": "Ivica Zubac", "heightValue": 2.16, "birthDayStr": "1997-03-18", "position": "中鋒", "age": 22, "playerId": "1627826" }
當別名指定了多個索引，可以指定寫某個索引
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": "克羅地亞", "teamCityEn": "LA", "code": "ivica_zubac", "displayAffiliation": "Croatia", "displayName": "伊維察 祖巴茨妹妹", "schoolType": "", "teamConference": "西部", "teamConferenceEn": "Western", "weight": "108.9 公斤", "teamCity": "洛洛杉磯", "playYear": 3, "jerseyNo": "40", "teamNameEn": "Clippers", "draft": 2016, "displayNameEn": "Ivica Zubac", "heightValue": 2.16, "birthDayStr": "1997-03-18", "position": "中鋒", "age": 22, "playerId": "1627826" }
ES 之如何重建索引
Elastic Search 是一個實時的分布式搜索引擎，為用戶提供搜索服務，當我們決定存儲某種數據時，在創建索引的時候需要將數據結構完整確定下來，與此同時索引的設定和很多固定配置將不能改變。當需要改變數據結構時，就需要重新建立索引，為此，Elastic 團隊提供了很多輔助工具幫助開發人員進行重建索引。
步驟
- nba 取一個別名 nba_latest, nba_latest 作為對外使用
- 新增一個索引 nba_20220101，結構復制於 nba 索引，根據業務要求修改字段
- 將 nba 數據同步到 nba_20220101
- 給 nba_20220101 添加別名 nba_latest，刪除 nba 別名 nba_latest
- 刪除 nba 索引
我們對外提供訪問 nba 索引時使用的是 nba_latest 別名
新增一個索引(比如修改字段類型，jerseyNo 改成 keyword 類型)
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" } } } }
將舊索引數據 copy 到新索引
同步等待，接口將會在 reindex 結束后返回
POST：localhost:9200/_reindex { "source": { "index": "nba" }, "dest": { "index": "nba_20220101" } }
異步執行，如果 reindex 時間過長，建議加上 wait_for_completion=false 的參數條件，這樣 reindex 將直接返回 taskId
POST：localhost:9200/_reindex?wait_for_completion=false { "source": { "index": "nba" }, "dest": { "index": "nba_20220101" } }
替換別名
POST：localhost:9200/_aliases { "actions": [ { "add": { "index": "nba_20220101", "alias": "nba_latest" } }, { "remove": { "index": "nba", "alias": "nba_latest" } } ] }
刪除舊索引
DELETE：localhost:9200/nba
通過別名訪問新索引
POST：localhost:9200/nba_latest/_search { "query": { "match": { "displayNameEn": "james" } } }
ES 之 refresh 操作
新的數據一添加到索引中立馬就能搜索到，但是真實情況不是這樣的。
我們使用鏈式命令請求，先添加一個文檔，再立刻搜索，會發現搜索不到
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：使用強制刷新
curl -X PUT localhost:9200/star/_doc/666?refresh -H 'Content-Type:application/json' -d '{ "displayName": "楊超越" }' curl -X GET localhost:9200/star/_doc/_search?pretty
方法二：修改默認更更新時間（默認時間是1s）
PUT：localhost:9200/star/_settings { "index": { "refresh_interval": "5s" } }
將 refresh 關閉
PUT：localhost:9200/star/_settings { "index": { "refresh_interval": "-1" } }
ES 之高亮查詢
如果返回的結果集中很多符合條件的結果，那怎么能一眼就能看到我們想要的那個結果呢？
高亮查詢
POST：localhost:9200/nba_latest/_search { "query": { "match": { "displayNameEn": "james" } }, "highlight": { "fields": { "displayNameEn": {} } } }
自定義高亮查詢
POST：localhost:9200/nba_latest/_search { "query": { "match": { "displayNameEn": "james" } }, "highlight": { "fields": { "displayNameEn": { "pre_tags": [ "<h1>" ], "post_tags": [ "</h1>" ] } } } }
ES 之查詢建議
查詢建議，是為了給用戶提供更好的搜索體驗。包括：詞條檢查，自動補全。
Suggester
- Term suggester
- Phrase suggester
- Completion suggester
字段
Term suggester
term 詞條建議器，對給輸入的文本進行分詞，為每個分詞提供詞項建議
POST：localhost:9200/nba_latest/_search { "suggest": { "my-suggestion": { "text": "jamse hardne", "term": { "suggest_mode": "missing", "field": "displayNameEn" } } } }
Phrase suggester
phrase 短語建議，在 term 的基礎上，會考量多個 term 之間的關系，比如是否同時出現在索引的原文里，相鄰程度，以及詞頻等
POST：localhost:9200/nba_latest/_search { "suggest": { "my-suggestion": { "text": "jamse harden", "phrase": { "field": "displayNameEn" } } } }
Completion suggester
Completion 完成建議
POST：localhost:9200/nba_latest/_search { "suggest": { "my-suggestion": { "text": "Miam", "completion": { "field": "teamCityEn" } } } }