python-3.x - 如何使用elasticsearch-dsl-py连接两个ElasticSearch索引？

Question

两个索引文件如下:

class First(Document):

    class Index:
       name  = 'first'
       
   case_id = Keyword()
   name = Text()
   
class Second(Document):

    class Index:
       name  = 'second'
       
   case_id = Keyword()
   status = Text()

我只想以SQL格式执行如下查询

select * from first as f, second as s where s.case_id = f.case_id or s.status = 'xyz'

如何使用 flex 搜索DSL查询进行查询？

Answer 1

Elastic Search不支持索引之间的联接
原因: flex 搜索不是关系型的，应将非规范化数据存储在此处。
摘自下面的elastic Doc:

Performing full SQL-style joins in a distributed system likeElasticsearch is prohibitively expensive. Instead, Elasticsearchoffers two forms of join which are designed to scale horizontally.

根据用例，使用嵌套或父/子映射来存储数据。
嵌套:如果嵌套文档的基数很低并且索引读取密集
parent / child :如果 child 的基数非常高，并且 parent / child 需要经常更新