MySQL 8.4 Release Notes
MySQL 版本模型分为两个主要轨道：LTS（长期支持）和创新。所有 LTS 和创新版本都包含错误和安全修复，并且被视为生产级质量。The MySQL release model is divided into two main tracks: LTS (Long-Term Support) and Innovation. All LTS and Innovation releases include bug and security fixes, and are considered production-grade quality.
Audience：如果您的环境需要一组稳定的功能和更长的支持期。Audience: If your environment requires a stable set of features and a longer support period.Behavior：这些版本仅包含必要的修复，以减少与更改相关的风险。数据库软件的行为。 LTS 版本中没有删除内容。只能在第一个 LTS 版本（例如 8.4.0 LTS）中删除（和添加）功能，而以后则不能。Behavior: These releases only contain necessary fixes to reduce the risks associated with changes in the database software's behavior. There are no removals within an LTS release. Features can be removed (and added) only in the first LTS release (such as 8.4.0 LTS) but not later.Support：LTS 系列遵循 Oracle 终身支持政策，其中包括 5 年优先支持和 3 年延长支持支持。Support: An LTS series follows the Oracle Lifetime Support Policy, which includes 5 years of premier support and 3 years of extended support.
Audience：如果您想访问最新的功能、改进和更改。这些版本非常适合在快节奏开发环境中工作的开发人员和 DBA，这些环境具有高水平的自动化测试和现代持续集成技术，可实现更快的升级周期。Audience: If you want access to the latest features, improvements, and changes. These releases are ideal for developers and DBAs working in fast-paced development environments with high levels of automated tests and modern continuous integration techniques for faster upgrade cycles.Behavior：除了创新版本中的新功能之外，随着代码重构、删除不推荐使用的功能以及修改 MySQL 以使其行为更符合 SQL 标准，行为也会发生变化。这种情况在 LTS 版本中不会发生。Behavior: Apart from new features in innovation releases, behavior changes are also expected as code is refactored, deprecated functionality is removed, and when MySQL is modified to behave more in line with SQL Standards. This will not happen within an LTS release.行为更改可能会产生很大影响，尤其是在处理与应用程序相关的任何内容时，例如 SQL 语法、新保留字、查询执行和查询性能。行为更改可能需要应用程序更改，这可能需要大量的迁移工作。我们打算提供必要的工具和配置设置，以使这些转换变得更容易。Behavior changes can have a big impact, especially when dealing with anything application-related, such as SQL syntax, new reserved words, query execution, and query performance. Behavior changes might require application changes which can involve considerable effort to migrate. We intend to provide the necessary tools and configuration settings to make these transitions easier.
Support：在下一个创新版本之前都支持创新版本。Support: Innovation releases are supported until the next Innovation release.
MySQL Server 和 MySQL NDB Cluster 都有创新版本和 LTS 版本。MySQL Server and MySQL NDB Cluster have both Innovation and LTS releases.
MySQL 连接器、MySQL Shell、MySQL 路由器、MySQL Operator for Kubernetes 有一个版本使用最新版本号，但仍与所有受支持的 MySQL 服务器版本兼容。例如，MySQL Connector/Python 9.7.0 与受支持的 MySQL Server 8.0、8.4 和 9.x 版本兼容。MySQL Connectors, MySQL Shell, MySQL Router, MySQL Operator for Kubernetes, have one release using the latest version number but remain compatible with all supported MySQL Server versions. For example, MySQL Connector/Python 9.7.0 is compatible with supported MySQL Server 8.0, 8.4, and 9.x releases.
当主要版本系列升级（例如 10.x）时，这些产品将遵循新的主要版本，同时继续支持 MySQL Server 和 MySQL NDB Cluster 的当前创新和 LTS 版本。When a major version line advances (for example, 10.x), these products will follow the new major version while continuing to support the then-current Innovation and LTS releases of MySQL Server and MySQL NDB Cluster.
拥有两个轨道会影响 MySQL 的安装、升级和降级方式。通常，您选择一个特定的轨道，所有升级都会相应进行。Having two tracks affects how MySQL is installed, upgraded, and downgraded. Typically you choose one particular track and all upgrades progress accordingly.
使用官方 MySQL 存储库时，所需的轨道在存储库配置中定义。例如，使用 Yum 选择 mysql-innovation-community 安装和升级创新版本，或选择 mysql-8.4-lts-community 安装和升级 MySQL 8.4.xWhen using the official MySQL repository, the desired track is
defined in the repository configuration. For example, with
Yum choose
mysql-innovation-community to install and
upgrade Innovation releases or
mysql-8.4-lts-community to
install and upgrade MySQL 8.4.x releases.
LTS 说明LTS Notes
LTS 系列中的功能保持不变，数据格式也不变，因此可以在 LTS 系列中进行就地升级和降级。例如，MySQL 8.4.0 可以升级到更高版本的 MySQL 8.4.x。还提供其他升级和降级方法，例如克隆插件。Functionality remains the same and data format does not change in an LTS series, therefore in-place upgrades and downgrades are possible within the LTS series. For example, MySQL 8.4.0 can be upgraded to a later MySQL 8.4.x release. Additional upgrade and downgrade methods are available, such as the clone plugin.
支持升级到下一个LTS 系列，例如 8.4.x LTS 到 9.7.x LTS，但不支持跳过 LTS 系列。例如，8.4.x LTS 无法跳过 9.7.x LTS 直接升级到 10.7.x LTS。Upgrading to the next LTS series is supported, such as 8.4.x LTS to 9.7.x LTS, while skipping an LTS series is not supported. For example, 8.4.x LTS can't skip 9.7.x LTS to directly upgrade to 10.7.x LTS.
创新说明Innovation Notes
创新安装遵循类似的行为，即创新版本升级到更新的创新系列版本。例如，MySQL 9.0.0 Innovation 将升级到 MySQL 9.3.0。An Innovation installation follows similar behavior in that an Innovation release upgrades to a more recent Innovation series release. For example, MySQL 9.0.0 Innovation would upgrade to MySQL 9.3.0.
主要区别在于不同主要版本的Innovation 系列之间无法直接升级，例如 8.3.0 到 9.0.0。相反，首先升级到最近的 LTS 系列，然后升级到以下创新系列。例如，将 8.3.0 升级到 8.4.0，然后从 8.4.0 升级到 9.0.0，是有效的升级路径。The main difference is that you cannot directly upgrade between an Innovation series of different major versions, such as 8.3.0 to 9.0.0. Instead, first upgrade to the nearest LTS series and then upgrade to the following Innovation series. For example, upgrading 8.3.0 to 8.4.0, and then 8.4.0 to 9.0.0, is a valid upgrade path.
为了帮助简化过渡，官方 MySQL 存储库将第一个 LTS 版本视为 LTS 和创新，因此，例如在本地存储库配置中启用创新轨道时，MySQL 8.3.0 升级到 8.4.0，然后升级到 9.0.0。To help make the transition easier, the official MySQL repository treats the first LTS release as both LTS and Innovation, so for example with the Innovation track enabled in your local repository configuration, MySQL 8.3.0 upgrades to 8.4.0, and later to 9.0.0.
创新版本降级需要逻辑转储和加载。Innovation release downgrades require a logical dump and load.
其他信息和示例Additional Information and Examples
有关其他信息和支持场景的具体示例，请参阅 第 3.2 节“升级路径” 或第 4 章，降级 MySQL。它们描述了执行就地更新（用最新包替换二进制文件）、逻辑转储和加载（例如使用 mysqldump 或 MySQL Shell 的转储实用程序），使用克隆插件和复制拓扑中服务器的异步复制。For additional information and specific example supported scenarios, see Section 3.2, “Upgrade Paths” or Chapter 4, Downgrading MySQL. They describe available options to perform in-place updates (that replace binaries with the latest packages), a logical dump and load (such as using mysqldump or MySQL Shell's dump utilities), cloning data with the clone plugin, and asynchronous replication for servers in a replication topology.