操作文档 ——读写文档
1、Introduction
https://www.elastic.co/guide/en/elasticsearch/reference/8.8/docs-replication.html
Each index in Elasticsearch is divided into shards and each shard can have multiple copies. These copies are known as a replication group and must be kept in sync when documents are added or removed. If we fail to do so, reading from one copy will result in very different results than reading from another. The process of keeping the shard copies in sync and serving reads from them is what we call the data replication model.
在 Elasticsearch，每个索引都被划分为碎片，每个碎片可以有多个副本。这些副本称为复制组，在添加或删除文档时必须保持同步。如果我们不这样做，从一个副本阅读将导致非常不同的结果，而不是从另一个。保持碎片副本同步并从中读取数据的过程称为数据复制模型。