ElasticSearch备考 -- Alias

一、题目

1) Create the alias `hamlet` that maps both `hamlet-1` and `hamlet-2`

Verify that the documents grouped by `hamlet` are 8

2) Configure `hamlet-3` to be the write index of the `hamlet` alias

二、思考

可以通过指定别名，来指向一个或多个索引，可以理解成一个linux系统重软链接。

别名创建三种方式

• 在创建索引时指定别名
• 索引模版中创建别名
• 对已有的索引创建别名

通过分析题目1)可以看出是使用第三种方式。题目2）是使用第一种方式。

三、解题

初始化数据

hamlet-1/_doc/_bulk
{"index":{"_index":"hamlet-1","_id":0}}
{"line_number":"1.1.1","speaker":"BERNARDO","text_entry":"Whos there?"}
{"index":{"_index":"hamlet-1","_id":1}}
{"line_number":"1.1.2","speaker":"FRANCISCO","text_entry":"Nay, answer me: stand, and unfold yourself."}
{"index":{"_index":"hamlet-1","_id":2}}
{"line_number":"1.1.3","speaker":"BERNARDO","text_entry":"Long live the king!"}
{"index":{"_index":"hamlet-1","_id":3}}
{"line_number":"1.2.1","speaker":"KING CLAUDIUS","text_entry":"Though yet of Hamlet our dear brothers death"}hamlet-2/_doc/_bulk
{"index":{"_index":"hamlet-2","_id":4}}
{"line_number":"2.1.1","speaker":"LORD POLONIUS","text_entry":"Give him this money and these notes, Reynaldo."}
{"index":{"_index":"hamlet-2","_id":5}}
{"line_number":"2.1.2","speaker":"REYNALDO","text_entry":"I will, my lord."}
{"index":{"_index":"hamlet-2","_id":6}}
{"line_number":"2.1.3","speaker":"LORD POLONIUS","text_entry":"You shall do marvellous wisely, good Reynaldo,"}
{"index":{"_index":"hamlet-2","_id":7}}
{"line_number":"2.1.4","speaker":"LORD POLONIUS","text_entry":"Before you visit him, to make inquire"}

题目一

Step 1、对已有索引创建别名

POST _aliases
{"actions": [{"add": {"index": "hamlet-1","alias": "hamlet"}},{"add": {"index": "hamlet-2","alias": "hamlet"}}]
}

Step 2、通过查询验证别名

POST hamlet/_count

题目二

方案一：创建索引指定别名

aliases 和 mappings 平级

aliases 中别名中花括号不用写任何内容

PUT /hamlet-3
{"aliases": {"hamlet": {}}, "mappings": {"properties": {"line_number": {"type": "text"},"speaker": {"type": "text"},"text_entry": {"type": "text"}}}
}

方案二：索引指定别名可以写

通过参数"is_write_index": true，可以别名执行写操作

POST /_aliases
{"actions": [{"add": {"index": "hamlet-1","alias": "hamlet"}},{"add": {"index": "hamlet-2","alias": "hamlet"}},{"add": {"index": "hamlet-3","alias": "hamlet","is_write_index": true}}]
}

四、总结

别名创建三种方式，注意每种方式的适用场景

• 在创建索引时指定别名
• 索引模版中创建别名
• 对已有的索引创建别名

参考资料

• Aliases | Elasticsearch Guide [8.1] | Elastic
• https://www.elastic.co/guide/en/elasticsearch/reference/8.1/index-templates.html

送一波福利：

福利一

有需要内推JD的同学，可以私信或留言，我帮您内推，流程快！！！

有需要内推JD的同学，可以私信或留言，我帮您内推，流程快！！！

有需要内推JD的同学，可以私信或留言，我帮您内推，流程快！！！

福利二

福利三