在深入了解 MySQL 组复制的细节之前，本节先介绍一些背景概念以及事务如何运作的概述。这提供了一些背景信息，有助于理解组复制所需的内容，以及经典异步 MySQL 复制与组复制之间的区别。Before getting into the details of MySQL Group Replication, this section introduces some background concepts and an overview of how things work. This provides some context to help understand what is required for Group Replication and what the differences are between classic asynchronous MySQL Replication and Group Replication.